Saga of my tired old 440T4 transmission...part deux

[drtidmore]

Well, first off a word of warning to everyone.  If you started the thread, there appears at the bottom the words, moderation options.  The only option in the pull down is delete.  If you click delete, you delete the WHOLE thread.  I was having issues totally backing out of a response with quote that the forum software insisted on bringing back from the editor memory.  As I was in middle of a response, I did not dream that delete, without warnings, would delete an ENTIRE thread, but that is what it does!  Turns out that not even the system admin can restore the thread.  

 

That said, I am restarting the thread and apologize the loss of the much appreciated posts.  At least the thread was fairly recent and no critical info was lost.

 

Edited May 29, 2017 by drtidmore (see edit history)

[drtidmore]

So, I will kick with a review of what has occurred up to the point of my accidental thread deletion.  

 

My '89 440T4 transmission, with 153K miles, out of the blue, no warning, decided to offer up ONLY 1st and reverse.  This tranny has been maintained throughout its life. About two weeks prior to the failure, I had replaced the filter and 7 qts of Dextron VI.  As in the past, no metal shavings and only the normal clutch muck around the magnet. For the following 2 weeks it shifted fine.  I pulled the tranny pan again but found nothing out of the ordinary.  After studying the 440T4 operation, I see that the 2nd clutch is not engaging for some reason as the 2nd clutch must engage for 2nd, 3rd and 4th gears, but NOT in 1st or reverse.  There are several things that could be the root cause, but only a teardown will tell the tale.

 

My first inclination was to have the 440T4 professionally redone.  89RDG reminded me that I could handle a rebuild and supported his claim with a really good video posted by turbokinetic over on the A-Body.net forum.  After watching the 440T4, 3 part video, I was confident tackling the rebuild.  Given that turbokinetic had many other videos posted, I started watching them.  One of the things that I wanted to ensure was that my rebuild was a strong as possible with as many updated/improved parts as possible.  Then I ran across turbokinetic's 9 part series where he rebuild the 440T4 in his '87 Park Avenue with the vastly improved charge pump and most of the rotating section of the 10 year newer 4T65E (grandchild of 440T4).  His goal was to create a tranny that would hang in there when he overhauled the 3800 in the PA as a turbocharged version.  The hybrid used the 440 case, valve body and final drive.  Some minor machining was required on a few of the 65E parts, but nothing major and certainly well within the abilities of any reputable machine shop.

 

So I spent hours pouring over both the 440T4 and 4T65E manuals (GM and ATSG) creating about 7 total pages of notes and parts lists.  Based on what turbokinetic stated, I knew that I needed a 97-99 4T65E as there were changes later that precluded the merging.  At first I was finding no 65Es in the DFW area and then I decided to see what craigslist might turn up.  BINGO!, a 98 65E-HD (from a Grand Prix supercharged 3800) as a local salvage yard from a recently wrecked '98 supercharged Grand Prix.  I purchased the transmission with the intent to gut it and put the remaining parts on eBay.

 

Then I ran across another of turbokinetic's videos where he dropped an entire 65E along with a standalone transmission control module from mid-90s 6.2/6.5L diesel, reflashing the shift points.  I already knew that attempting to use the 65E posed mechanical issues as it is longer than the 440T4 due to the addition of another drum/band in the 65E which would require a shorter drive shaft on the passenger side.  The 65E-HD would also require mixing the inner CV joints as the 65E-HD outputs are a larger diameter than the non-HD.  

 

This presented me with a fork in the road.  My plan had been to tear down the 65E, have the parts that require machining modified and then rebuild the parts that I would be installing in the 440 case, but IF even on the more remote odds that I might use of the 65E intact, I would NOT want to modify those parts.  

 

On the one hand, doing the 440/65E hybrid would result in a much more robust tranny in a 440 case with no need to change any mounts, CV joints, drive shafts BUT the transmission would be a one off.  Dropping in a rebuilt 65E-HD  would keep the tranny design integrity, but would require adding in a stand alone TCU (needs only throttle position, engine RPMs and vehicle speed), modifying the passenger side mount and customized CV joints. Plus the 65E-HD has a MUCH beefier final drive which I could NOT install in the 440.  Both have advantages and disadvantages.

 

So, this past Saturday, I tore down the 65E.  Was VERY pleased with the condition I found.  The only section of the tranny showing ANY signs of wear was the input clutch with some of the frictions having small chunks missing.  There were no real signs of slippage anywhere other than what appeared to be some slipping between the forward drum and its associated engagement band which when opened up the forward band servo, I found that the servo seal was allowing some blow by (the later improved version fix the issue) which was likely allowing that forward drum to slip to some extent.  There was some super minor, and very typical scorch marks on most of the steels but all the fractions and seals are being replaced regardless.  Everything is torn down, bagged/tagged and stored in plastic tubs.  

 

With the 65E case empty, it is a LOT lighter and so I have decided to change my original plan and now tear into the Reatta.  I need to take some measurements as to the passenger side tranny mount.  It is going to be close due to the way GM changed the mounting point to pretty much retain the same plane of attachment despite the 65E being longer.   I plan to bolt the empty 65E case unto the 3800 and look over everything as well.  Yes, this is extra work, but it will clarify what issues might present themselves and at this stage the case is a lot easier to handle. 

 

 

Edited May 29, 2017 by drtidmore (see edit history)

[drtidmore]

I moved my pics of the J-28476 over to a separate thread so as to make future searches easier. 

 

Edited May 30, 2017 by drtidmore (see edit history)

[drtidmore]

...and a few pics of the 4T65E-HD teardown.  

 

Here is the side case on the 65E.  Unlike the 440T4 which is stamped, the 65E has a SOLID, structural cast side pan.  This eliminates the spider bracket needed on the 440.  In this pic I have already removed the bracket that attaches to the driver's side mount.

 

Here is a shot of the HD differential.  The pinion gears are HUGE!  Notice the black, hardened pinion shaft.

 

Here is the final drive sun gear shaft.  Note the lack of wear and this is after 20 years and 106K miles behind a supercharged 3800

 

Here is the other end of the final drive sun gear shaft. Again no wear!

 

Here is the final drive sun gear...no wear to the spline or the gear

 

Here is a shot of what hides behind that beefy side pan on a 65E

 

Here is the internal wiring harness.  I fully expect the clips to break off as I removed them due to the age and heat, but not a single one broke

 

Here is the backside of the charge pump.  Note the bearing inside the rotor. On the 440T4 the bearing is in the case itself and the rotor has no other support.  This is what lead to pump bearing failures in the 440T4. The 65E design fixed that issue

 

And this is a shot of the channel plate behind the charge pump.

 

Here is the charge pump drive shaft, A tiny bit of shine to the wear points, but NO actual metal worn away.  I will likely replace it regardless as it is not all that expensive.

 

Here is the charge pump opened up.  Note that the 65E is an 11 vane pump as compared to the 9 vane on the 440T4

 

Here is the charge pump slide.  This slide is what allows the pump to be a variable capacity pump.  Note the slight scorching marks.  I am investigating if this is normal and indicative of needing repair. 

 

Here is the 4th clutch.  What you can't tell is that this one is heavier and a dual friction plate design as opposed to the lighter single friction plate design in the 440T4.  The 440, 4th clutch can handle about 50 HP with its single clutch (i.e. low engine RPM when 4th is engaged).  The dual heavier 4th clutch in the 65E is capable of handling 150HP.

 

Here is the top friction plate in the 4th clutch stack.  Note it looks pristine.  There was a slight amount of scorching on the steels in the 4th clutch but remember this was behind the supercharged version of the 3800.

 

Here is what happens when GM chose to NOT use hardened parts.  Until the 2003 version, the non-hardened 4th clutch hub/shaft wore as shown and would eventually strip...then no overdrive!  A new hardened version of the 4th clutch hub/shaft will be going into the rebuild

 

Here is so-so shot showing the dual chain drive.  I failed to get a good shot of it.  The chain was in good shape but it is the non hardened version (this chain had single blue link: hardened has 2 blue links) so again, hardened will be going in on the rebuild

 

Here is a shot of one of the big difference in the 440T4 and the 65E.  The 440 has a 2/1 band while the 65E has a 2/1 band AND a forward band with a sprag coupling the two.  This means that there is also an extra servo and band inside the 65E.  These changes allowed GM to eliminate the release/engage shifting in the 440 and go with a purely additive shift pattern in the 65E.  This makes shifts smoother and with less wear.  BUT as you can see there are scorch marks on the forward drum (left drum in pic).  I traced this to a flattened seal in the forward drum servo that was allowing some blow by during engagement and therefore some slippage on the drum until the servo would finally catch.  Not sure if this is a problem and if I do the 440/65E hybrid these parts will not be used, but if I go with the 65E-HD drop in, I may need to replace this drum.

 

Here is view down the throat of the input shaft & housing with all the 3rd and input clutches in place.  This is the pre mechanical diode sprag design which changed the teeth on the frictions to be rounded vs rectangular.  I will be replacing the one way input & 3rd clutch sprags with the newer mechanical diode design. 

 

Here is a shot of where I found impending doom for this tranny.  Up to this point, everything looked almost too good.  Not that this meant that the tranny was in imminent danger of failure but with the ongoing disintegration of the input clutch frictions, it was only a matter of time.  Virtually all the input clutch frictions had small area of material decay, but this one was particularly bad with chunks totally missing. 

 

On contrast, the adjacent 3rd clutch frictions looked almost new.  You can see that Borg Warner frictions were used in this tranny.

 

and to make sense of how things stack in the 65E here is an exploded view diagram

 

Edited May 30, 2017 by drtidmore (see edit history)

[D-a-n-i-e-l]

So is the plan now to use the 65 in a complete state?

[drtidmore]

2 hours ago, D-a-n-i-e-l said:

So is the plan now to use the 65 in a complete state?

That has not been ruled out.  At the moment, I am preparing to tear into the Reatta and then do a test fit of the empty 65E-HD case into the Reatta.  I already know it bolts up to the 3800 properly, likewise the driver's side mount works as designed.  What I don't yet know is how much I will need modify the passenger side mount.  It should fall in the same general plane even though the 65E is longer as on the 65E I can attach at the tranny case to differential housing interface.  I do know that I will have mix up the CV joints was the 65E is an HD model so the outputs from the tranny are a larger diameter than the 440T4 or the 65E std.  The 65E-HD will also require that I swap out the passenger side drive shaft for one from a SC Riv.  Then there is the issue of the TCU needed to control the 65E.  The standalone TCU from the 91-93 6.2/6.5L diesel which also used the 65E0HD works once the shift points are reflashed.  It only needs the throttle position, engine RPM and vehicle speed inputs and can share those with the existing Reatta ECM.  I can derive the gear shift point switches that the 440 provided to the Reatta ECM by monitoring the ground status of the two shift controlling solenoids with a simple circuit.  My thoughts on the TCC is to use OR logic to allow either the Reatta ECM or the standalone TCU to control the TCC.  Using the 65E in a complete state is NOT straightforward but it is not really rocket science either.  As I have compared the effort for both approaches, I really need a few more of my questions answered before I make decision.

 

I posted the 65E teardown pics from an informational perspective rather than a firm statement of which way I will go.  I really like the idea of the intact 65E-HD but at the same time if I go with the 440/65E hybrid I don't have to mess with the mount/CV joints and drive shafts which is  appealing.  I really like the beefy final drive of the 65E.  As the pics showed, even after 106K miles behind a SC 3800 there was NO wear.  Unfortunately there is NO way to use it in the 440 case, so if I go down the 440/65E I get the improved charge pump, 2nd, 3rd, 4th clutches, the improved forward planetary, but have to keep the 2/1 drum, the rest of the final drive from the 440 and the hydraulic valve body control.   It is a mixed bag.

 

david

[89RedDarkGrey]

• CONS OF HYBRID:
• The Hybrid requires mod of the side case
• The Hybrid won't have the HD differential
• The Hybrid won't have the compounding gears
• The Hybrid will only have 1 chain

 

• CONS OF T65E-HD:
• Axle CV swap
• Added TCU controller
• Questionable passenger side mount
• Added failure codes/monitoring PIDS 

 

• PROS OF HYBRID:
• Certain high-failure parts are eliminated
• No question of case fitment
• No change of axle(s)
• No change of electronics
• Faster build time  

 

• PROS OF T65E-HD:
• More reliability
• Longer service life
• Reduced stress on engine
• Smoother shifting
• Increased MPG
• Increased monitoring capability
• All HD parts coupled to standard 3.8L NA

 

I might have missed a few- but that's the way I see it. If the T65E-HD fits- I'd say GO FOR IT

[Ronnie]

It seems one comparison was left out.

 

CONS of 440T4

• Weaker than Hybrid or 65E
• Non-hardened parts.
• Cannot withstand Supercharger power (for long).
• Parts wear quicker than 65E parts
• Shorter expected life of transmission.

 

PROS of 440T4

• Complete Rebuild kits available.
• Cheapest to rebuild.
• No modifications needed to trans, axles or mounts.
• Quickest turnaround time.
• Would probably last the usable life of the car.
• Might last the usable life of the owner.

 

 

 

 

 

 

Edited June 1, 2017 by Ronnie (see edit history)

[drtidmore]

89RDG, Ronnie,

More or less in line with my thoughts but a few clarifications from my perspective.

• CONS OF HYBRID:
• The Hybrid requires mod of the side case  (no mods to 440 case/pans required as all the 65E stuff goes INSIDE)
• The Hybrid will only have 1 chain (actually it WOULD get the dual phase drive/driven sprockets and dual hardened chain) 

A couple of missing hybrid cons.  

• minor machining of several 65E parts making them one off parts (i.e. future repair headache)
• crafting an adapter bushing to modify the 440T4 channel plate output shaft area to the upgraded 65E design.  This is a critical piece as it sets the 4th clutch pack clearance.  Not a convoluted part, but one that has to be machined from scratch. 

There is some debate as to the preference of the single chain design in the 440 vs the dual chain in the 65E.  The dual chain is quieter, since the load/unload points on the sprockets are 180 degrees out of phase so the noise they create cancels each other and at least in the hardened version the dual chains would have a longer life than the single chain.  (the whole issue of noise seems a bit academic to me as I have never heard ANY noise for the 440T4).   At least some 65E owners have experienced one of the two chains breaking and from what I gather, such is a nightmare of a mess.  At the same time, it appears that those failures were ALL the original non-hardened chains and I would be installing the hardened version. There is a kit (slightly wider, hardened sprockets, hardened single chain) for the monster engine crowd, but it comes with a VERY expensive price tag!   It is possible to modify the existing 440T4 single chain drive/driven sprockets for using in the hybrid 440/65E, but I would likely just go with the 65E design and the new hardened chains.  (both my 440 and the donor 65E-HD use the same 37/33 drive/driven sprocket ratio, so no overall drive ratio change would occur if I used the dual chain setup in the hybrid 440/65E.           

• CONS OF T65E-HD:
• Added failure codes/monitoring PIDS (codes would NOT set the Reatta SES light regardless (no connection)  and having insight into the transmission operation via the TCU OBD-2 connector is actually a good thing in my book.  

•  PROS of 44T4
• Complete Rebuild kits available. (granted there would NOT be a turnkey kit for the hybrid, but spec'ing out a set of parts is NOT that big an issue as the starting point would be the 440T4 basic overhaul kit regardless.  And of course the 4T65E-HD intact actually has MORE rebuild kit options than the 440T4. 
• Quickest turnaround time. (the time delta between ANY of the 3 options is not significant)
• Would probably last the usable life of the car. (none of the options has a lock on usable life as compared to life of car)
• Might last the usable life of the owner. (as my Reatta will go to my daughter who wants it, I am looking to make it last WAY longer than my usable life, whatever that might be.)

 

• PROS of 65E OR 440/65E hybrid
• Output shaft from transmission is support by the CV hub which in turn is supported by the case rather than bearings inside the internal rotating section.  This change can actually be done on the straight 440T4 using the same aftermarket repair part that would be used in the hybrid. (Fitzall/Techpak #84125LB axle stabilizer).  They also make a kit for the passenger side as well.  

It is a real mixed bag.  If not for the machining of the 65E parts in the hybrid and the need for the custom 4th clutch bushing, the hybrid would likely have the advantage, but no way around those so it comes down a debate whether is it better to have one-off stuff inside the transmission or external in the CV joints and the passenger side drive shaft.  The intact 65E-HD is a bit more complicated due to the need for the standalone TCU and getting the shift points reflashed, the added wiring and one-off CV joints and passenger side drive shaft, but those are offset by the added strength of the final drive section of the 65E-HD.  I can argue either side with equal conviction.  Until I get a few more data points regarding the use of the intact 65E I simply can't make an intelligent, informed decision.  IF I HAD to make a decision at this point, the least line of resistance is a rebuild of the 440T4 with only modest upgrades to hardened versions of a couple of key parts known to wear in the 440.  The 440/65E hybrid would be a big improvement in the tranny overall and would require the least amount of actual custom stuff but it would result in a one-off transmission, albeit a stronger, vastly improved, one off.  The intact 65E-HD drop in appears to be the most challenging option due to the variety of things external to the transmission that are required, but the end result would be a transmission best capable of handling an upgraded engine should the future open up that potential. 

 

Edited June 1, 2017 by drtidmore (see edit history)

[Ronnie]

18 minutes ago, drtidmore said:

 IF I HAD to make a decision at this point, the least line of resistance is a rebuild of the 440T4 with only modest upgrades to hardened versions of a couple of key parts known to wear in the 440.

To me that is the most logical path forward unless you plan to do performance engine upgrades. So far I don't think I've read that you have plans to do that. Although the 440T4 isn't a strong transmission that can be treated rough, I think it is adequate for it's intended purpose.

[drtidmore]

46 minutes ago, Ronnie said:

To me that is the most logical path forward unless you plan to do performance engine upgrades. So far I don't think I've read that you have plans to do that. Although the 440T4 isn't a strong transmission that can be treated rough, I think it is adequate for it's intended purpose.

While it may seem the logical path forward, it is a deadended one from my perspective.  The only way I would go that route is if there was an absolute showstopper on the hybrid and honestly I don't see that happening.  I have an excellent condition 65E-HD ready to either be totally rebuilt OR become a donor to the hybrid.  I do still have the option to revert to a straightforward build of the 440 at any point, but if I was already to the point of having the 440 output shaft machined (a couple of bearing races need to be removed), I would have to get a replacement salvaged one and from what I have found, those are not readily available as they seldom fail.  Once I have it machined, it would be unusable in a straightforward 440 transmission.  

 

One thing that concerns me about the 440T4 is that while a pot load of them were produced, parts are beginning to thin out already since it was last installed by GM in the early 90s.  The 65E however was only recently dropped from production use and parts/upgrades are plentiful as is general knowledge.

 

Another thing I forgot to add as a PRO to the intact 65E and to some extent the 440/65E hybrid is the HUGELY superior GM service manual.  GM undertook a complete overhaul of the manual, the organization and all its graphics compared to the 440 or the 4T60E.  The difference between it and the one for the 440T4 is like have a native language book vs one in a poorly spoken dialect.  Yes, the 440T4 SM is acceptable but it takes a LOT more concentration on what is being presented as compared to the much more logical and clearly presented 4T65E manual.  The ATSG manuals for both are about the same and great for "just the facts" during an overhaul, but if you want to really understand the transmission the GM manual IS the source of that knowledge.

Edited June 1, 2017 by drtidmore (see edit history)

[89RedDarkGrey]

 

1 hour ago, drtidmore said:

• CONS OF HYBRID:
• The Hybrid requires mod of the side case  (no mods to 440 case/pans required as all the 65E stuff goes INSIDE)

 

I'm sorry- I meant the 440T4 Channel Plate had to be modified for the installation of a 4T65E 4th Clutch Hub if going the Hybrid route. I mixed up the Case.

 

[D-a-n-i-e-l]

What about a 60hd? I used one once in my earlier SC series one swap. Still had to piggyback a ECM bc I have an 89. 

I do love the idea of a 65 in a Reatta and even more the hybrid idea. 

 

[drtidmore]

16 hours ago, D-a-n-i-e-l said:

I do love the idea of a 65 in a Reatta and even more the hybrid idea. 

 

The real draw to the 65E-HD over the hybrid is the improved shifting and the heavier final drive of the 65E-HD and between those two, it is the heavier final drive and output shaft that is the real draw.  If there was a way to put the 65E HD final drive in the 440 case, I would likely have already made my decision in that direction.  I do like the 65E's removable differential housing but that is not a deal maker for me.  While the electronic control of the 65E offers good non-invasive diagnostics and a simpler valve body, the hybrid's avoidance of the TCU requirements is very attractive.  

 

The hybrid incorporates a good 90+% of the 65E's improvements.  In fact, the only moving parts retained from the 440T4 are the torque converter, the 2/1 drum/band, the output shaft and the final drive/differential section.  I won't know until I tear down the 440T4 if the upgraded hardened pinion pin and gears were part of my '89 (installed in some '89 440T4s), but if NOT, then a new 440T4 differential WITH the hardened pin and gears will be a requirement.  The hybrid has to retain the 440T4's 245mm torque converter as the 440T4 bell housing precludes the use of the 65E's higher output 258mm TC (bummer), but a reman 245mm TC with carbon fiber clutch is an option. 

 

As I have mentioned, the hybrid brings over the 65E's charge pump, dual chain drive/driven sprockets with a new hardened chain set, turbine shaft, entire 4th clutch hub/shaft/clutch, entire 2nd clutch assembly, entire input shaft/housing with its improved input and 3rd clutches, mechanical diode sprag clutches, input sun gear, hardened reverse reaction shell, input carrier assembly, reaction carrier assembly, but retains the 440T4's valve body, 2/1 drum/band and entire final drive section.  

 

David A used the 440T4's 3rd clutch piston assembly since the retained 440T4 valve body was calibrated for it, so I would do likewise. 

 

Obviously, the 440T4s governor and servos carry forward. By installing the Fitzall/TechPak axle stabilizer bearing/bushing kit, the hybrid also gains that 65E's design of supporting the output shaft on the case rather than inside the rotating section.  Fitzall offers the same kit for the passenger side but that side is pretty well supported within the differential already.  

 

The hybrid build requires the following modifications

a .050" step must be machined into the back side of the 65E 2nd clutch drum (similar to how the 440T4 2nd drum was machined)  

.020" be removed from the 65E 2nd drum shaft

.070" be removed from the 65E input housing shaft

.080" be removed from the 65E driven sprocket shaft (due to retention of the 440T4s driven sprocket support)

The outer bearing race on the 440 output shaft be machined off (to allow tranny fluid to better flow to the support bearing)

The inner bearing race collar (nearest output end) on the 440 output shaft must be removed but leaving the oil dam side intact

The retained 440T4's driven sprocket support MAY require minor clearance slots be created to allow the 2nd clutch drum to not interfere

The installation of the Fitzall output shaft axle stabilizer combo bearing/seal and adapter bushing

The whole-cloth creation of an adapter bushing to set on the Fitzall axle stabilizer to adapt from the 440T4's 4th clutch bearing design to the 65Es 4th clutch thrust washer design.  This adapter is critical as it sets the clearance in the 4th clutch pack.  

Lastly, the TransGo SK-440-JR system correction kit needs to be installed.  This kit fixes a number of issues on the 440.

 

The basic 440T4 overhaul kit is the starting point and then you separately order up the frictions/steels/bands for the 65E, and new molded seal clutch pistons for the clutches.  Gathering up the needed parts for the overhaul is NOT a difficult task.  As you build up the 65E stack for the hybrid, clearances must be verified along the way.

 

I want to once again give credit to David Allen (turbokinetic) for pioneering (feasibility as well as implementation) the hybrid 440/65E on his '87 Park Avenue last year.  He reports that other than the 2nd gear shift being a tad harder than Buick originally designed (due to the installation of the TransGo SK-440-JR system correction kit), there is absolutely nothing he would change on the hybrid.  He pointed out that the 2nd shift can be softened by slightly enlarging the opening specified by TransGO on the separator plate of the valve body.

 

In either the hybrid or a full up 65E-HD, I plan to use Raybestos Gen 2 frictions and steels.  This is a bit of overkill, but the Gen 2 frictions have a higher coefficient of friction, generate less heat, have better fluid flow to carry away heat, and laster longer. 

[drtidmore]

Time for an update!

I chased going with a full up 65E drop-in for the last week or so.  I knew it posed issues but there was a real mental resonance to have the HD tranny.  In addition, I quickly realized that parts for the 440T4 were fading away while the 4T65E offered a world of replacement parts and improvement options.  Beyond the issue of the minor mods needed on the tranny passenger side bracket (tranny to frame mount), there was the issue of the drive shafts on both sides as the HD tranny required the HD CV joints coming out of the tranny (larger diameter) and the passenger side requiring the use of a drive shaft from a SC Riv.  Then there was the BIG issue of controlling it since the '89 was pre-PCM controlled transmissions.  David A, and others, had been able to get the 65E functioning with the TCU from an early to mid 90s GM 6.2/6.5L diesel pickup TCU reflashed with modified shift points (he just scaled the values upwards).  David had not been totally happy with the shift points but they were acceptable.  I thought I had found a perfect solution from Powertrain Control Solutions in their TCM-2000 as it DID fully support the 4T65E including the complete harness, but unfortunately discovered that they had superseded the TCM-2000 with the TCM-2800 about 6 months ago and no longer supported any of the 4Txxx trannies and had no TCM-2000s remaining nor any of the 4T65E harnesses...bummer!   Yes, I could have build up my own control program for the TCM-2800 and I even downloaded and worked with it's programming tool.  Their 4Lxxx cable with a couple of minor pin changes would have worked fine for the harness.  I even figured out how to have the TCM-2800 mimic the 440T4's clutch switch outputs so that the Reatta ECM could managed the torque on the 3800 properly.  

 

In the end, with resolutions to all the technical issues identified, I finally put a pencil to the cost and it just did not make a lot of sense.  A full drop-in cost including the rebuild of the donor 4T65E-HD, the needed parts to mod the CV/drive shafts and the TCU was going to cost a tad over TWICE that of the hybrid 440/65E.  The biggest cost was the TCM-2800 at a tad over $1000.  Going with the diesel TCM was a bit cheaper, but not tremendously, as beyond the diesel TCU, I would need several additional items to monitor/reflash the diesel TCU (tuning the shift points would require trial and error to perfect) and my preference was a fully supported 3rd party TCU with really good software tools for the tuning process.  I might add that David A, having experience with both the hybrid and the full-up 65E paths, recommended the hybrid as the better overall solution to a stronger transmission. 

 

So, I am back to my original plan of doing the hybrid.  I do not consider the time and effort chasing the full-up 4T65E-HD a waste as I learned quite a bit in the process and that knowledge may well come in handy at some point in the future.  The hybrid offers about 90% or slightly more of the improvements GM made in the 4T65E over the 440T4.  I have started ordering up parts to rebuild the 65E parts that will be going inside the 440 case.  Before I rebuild those items, several require minor machining, so that will done first.  I have to design and have machined an adapter/bushing to modify the 440T4 channel plate 4th clutch support from a bearing design (440T4) to a thrust washer (4T65E).  This is not a complex part, but it will take a few iterations at the lathe to get the exact height of the part to achieve the needed 0.010" clearance in the stacked 65E 4th clutch assembly and I will NOT be able to make the final adjustments until I pull and tear down the 440T4 in the Reatta as I have to stack against the 440T4's driven sprocket support and channel plate (fyi, there are NO shimming options for this particular clearance, it just has to be RIGHT).  I am going to wait on the Reatta teardown until I have all the known needed parts on hand, the known mods on the 65E parts complete, the 65E clutch packs and pistons rebuilt and the near final 4th clutch hub bushing/adapter complete.   I plan to drop the entire cradle rather than attempting the half cradle approach as I want to replace all the cradle bushings and the engine/transmission mounts anyway.  While I have the cradle out, I plan to send it out for media blast and powder coating , then I will spray the interior of the cradle pieces with undercoating.  By the time the cradle is back I will have the 440/65E hybrid built and potentially bolted back onto the engine. 

 

The only unknown at the moment is the status of the 440T4 differential pinion shaft.  From my research, some '89, 440T4s had the hardened shaft and pinion gears, but most did not.  89RDG's broken tranny case experience is what happens on the non-hardened differentials when wear inevitibly leads to the pinion gears seizing on the pinion shaft and that problem was sufficiently widespread that GM hardened the parts across the board starting on the 4T60E (i.e. '91 Reatta).  Finding the hardened version of the 440T4, 3.33 differential used in the Reatta (new or salvaged) is like finding NOS ABS leads...  I have determined that the hardened pinion shaft used in the 4T65E and 4T60E is dimensionally identical to the non-hardened one used in the 440T4, so I do have a way to upgrade my differential regardless. There is simply no way that I am putting a non hardened differential into the hybrid build.  

 

Now the real fun begins!

[89RedDarkGrey]

(Bump)

[Ronnie]

44 minutes ago, 89RedDarkGrey said:

(Bump)

This is a good topic but why bump a topic that's not been active in six months without making a comment?  drtidmore hasn't signed in since last August.  Am I missing something?

[89RedDarkGrey]

I'm sorry. I don't know the exact etiquette of asking "hey- what's going on?" I didn't know he hasn't signed in for 6 months. Is he ok? What happened? Did I miss something?

[Ronnie]

No problem.  If you had said, "hey- what's going on?" I would have understood. I don't know what happened to him. I wish he would come back and fill us in on his progress rebuilding his transmission. He is a smart man and has a lot to offer on the forum. I hope he isn't gone for good.

[handmedownreatta]

a few questions from someone that has no clue.is it possible to use the reatta valve body or maybe a 91 reatta valve body in a 65e?are none of those performance trans rebuilders building a replacement 440-t4 using 65e parts or at least offering a kit including the parts already machined?

[padgett]

One comment, though time the 440T4/4T60 went through continual improvement and many TSBs and the last iteration had the dual clutches mentioned. The final 91 4T60 n was a much better trans and good for up to about 250 lb-ft of torque.

 

Also AFAIK the 4T60HO was only used with the 1990-91 turbo Grand Prix and are quite hard to find.

[handmedownreatta]

30 minutes ago, padgett said:

One comment, though time the 440T4/4T60 went through continual improvement and many TSBs and the last iteration had the dual clutches mentioned. The final 91 4T60 n was a much better trans and good for up to about 250 lb-ft of torque.

 

Also AFAIK the 4T60HO was only used with the 1990-91 turbo Grand Prix and are quite hard to find.

wiki says A version of the 4T60 called the 4T60-HD, which incorporated upgraded final drive hardware but was otherwise mechanically indistinguishable from standard units, was used in the 1989-1990 Pontiac Grand Prix with the turbocharged engine.of course they are often wrong.

[Ronnie]

The last we heard @drtidmore was working on hybrid version of the 440-T4 and the 4T60 that would be a stronger transmission. I don't know if it would be equal to a 4T60 used in the Grand Prix but it should be able handle the power of the stock Reatta engine and most likely the SC engine too. For some reason he just left the forum. I would really like to know how his transmission project worked out.

[padgett]

I guarantee nothing from memory.

[2seater]

I agree I miss his input also. I thought the photos and posts were first rate.  

[DAVES89]

If you remember he has a bit of a history of posting and then disappearing. I hope he comes back. May seem weird to some but when someone stops posting and I know their name I always check the obits. 

[handmedownreatta]

5 hours ago, padgett said:

I guarantee nothing from memory.

i was looking at the wiki page yesterday.always good info source but never completely right.