RetroJohnny

1989 Transmission Lag

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Hello everyone, as I continue to fix up my 89' Red coupe, I have noticed lately that it really does not like shifting going up at hills at all. It will shudder and jolt before it decides to shift. While on a flat road, it does quite well, but it likes to hesitate shifts during fast acceleration. Could this be as simple as flushing the system and adding all new trans fluid, or is it something more internal? The car just hit 180,000 miles with a rebuilt 3800 in it with 30,000 miles on the engine. But i have heard these transmissions start to fail and deteriorate after 170k. Any ideas? Thanks!

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Is the fluid dark and smell burned at all? Is the fluid level correct? Before going to the trouble of a fluid and filter change, try adding Seafoam or Lucas transmission additive. The other thing that may sound counterintuitive is an ignition misfire. This will show up under load, such as when it goes into high gear and the TCC locks up under moderate throttle. Take a close look at the ignition coil pack and the ICM module under the coils to see if there are signs of overheating such as soft or leaking potting material in the module. Pull the line from the vacuum modulator at the top front of the transaxle and check for fluid present in the vacuum line. Check the throttle valve cable for proper adjustment at the throttle linkage.

It may indeed be the transaxle is getting tired, but I would check other items first which cost little or nothing.

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Yes, I agree with 2seater- under load you really need a powerful ignition. I would also change any questionable fluid and filter, and closely examine the Modulator, and it's vacuum source. Climbing hills lowers the manifold vacuum, and you need all you can get to run the systems. A leaky HVAC vacuum line, accumulator, faulty check valve, cracked hose, and check the large cap near the EGR, where a brake booster would normally plug in.

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Thanks you guys for the ideas! I am gonna put some Lucas in there and top it off with new transmission fluid. But no the fluid is still quite red and doesn't seem like it has any mineral build up going on. And no signs of a burn or leak from it either, hopefully a cheap additive remedy will smoothen things up! If not I may explore the ignition coil idea and the Modulator. I will report back in a few days to let you know if it is a serious issue or not.. Thanks for the input again!

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Alrighty folks, today was the ultimate test to see what was up with the transmission. I topped it off with new fluid and some additive, so earlier on this cold day I wanted to see if the gears shifted smoother. So i started from zero and mashed the acceleration(that is a very rare thing for me) And all was good until about 50 miles per hour, the engine revved up to as high as the screen would show and the tranny stalled out, and it was loud and hard to listen too (didn't fail, just gave out for a moment) so that put some shivers on my back, scaring myself to beileve I just screwed up the tranny more than it is. But it still operates under normal conditions for now, but I can see not too far down the road having very very serious issues with this automatic transmission. What step should I take first to resolve this? Take it in to someone experienced in transmissions to see their diagnosis? Or wait it out and see? Or what? Thanks for your time again.

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It's possible the filter is clogged causing the transmission to starve for fluid under the conditions you described. Changing fluid and filter would be the cheapest and easiest thing you could try yourself. After that taking it to a transmission specialist is in order.

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Ronnie is right, the next thing to check is the filter. Maybe I am misunderstanding, but it sounds like you installed the additive and did a full throttle test from a cold start? I hope that I didn't get that right?

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Okay filter will be the first thing to change! And no no 2seater. I let the car heat up and drove it around for 30 minutes before full throttle. I wouldn't run it cold

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The initial issue you described of it hesitating going up hills is very common in these transmissions when they're starting to get worn. At your milage it's not suprising at  all. Basically what's happening is it's not wanting to shift out of overdrive. I have an 88 I drive every day that has been doing this for about 15,000 miles. When it does it, I either pull it out of overdrive manually, or simply lift my foot off the accelerator. This causes it to drop out of overdrive and into 4th and then you can proceed from there. 

 

Like I said, I've driven the car over 15,000 miles this way and it hasn't been a major issue.

 

I would however change the fluid and filter just to make sure you don't have awful fluid and to check for bits in the pan. 

Edited by NCReatta (see edit history)
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Since we are working with opinions here -

 

Could it be the Lockout on the torque converter?   This solenoid activated (I think solenoid) lock locks in the engine to the transmission for a direct drive for improved gas mileage purposes.  It was introduced on most makes in the 80's and 90's.  Torque converters slip, which means more rpm and energy to run, less gas mileage.

 

Therefore, with computer technology in the 80's and 90's it became possible to lock the connection between the engine and transmission BUT when the engagement does not release - such as on brake or a demand request for acceleration, then the engine will shudder, stall or otherwise complain.

 

Think of it as a manual transmission and you are in 5th gear overdrive going up a hill and losing speed (momentum).  What do you do, you downshift until you get an engine speed that will accelerate you up the hill.  

 

Perhaps your Reatta has a stuck lockout that isn't disengaging.  That's one reason Marck is able to get acceleration by manually shifting out of overdrive or stopping the "request" to accelerate by lifting off the peddle. 

 

I agree the transmission is getting worn down.  A flush never hurts.  When I was a technician, we used to flush the transmission not drop the pan and change the filter.  A complete flush at a Midas or such usually runs between $90 and $130.  Under normal circumstances, this is a 60,000 mile service.  However, I am in agreement that the mileage on the transmission concerns me.  It depends on whether you want to keep your Reatta long term.  In that case, replace the transmission from a reputable shop and you will be set for another 150,000 miles. 

 

You can try the flush 1st, which may "clean" the torque converter clutch from sticking and provide better pressure readings for your transmission or drive it the way it is with more manual shifting while setting aside the money for a new transmission.   

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8 hours ago, NCReatta said:

The initial issue you described of it hesitating going up hills is very common in these transmissions when they're starting to get worn. At your milage it's not suprising at  all. Basically what's happening is it's not wanting to shift out of overdrive. I have an 88 I drive every day that has been doing this for about 15,000 miles. When it does it, I either pull it out of overdrive manually, or simply lift my foot off the accelerator. This causes it to drop out of overdrive and into 4th and then you can proceed from there. 

 

Like I said, I've driven the car over 15,000 miles this way and it hasn't been a major issue.

 

I would however change the fluid and filter just to make sure you don't have awful fluid and to check for bits in the pan. 

i don't have a five speed auto like marck but my trans bucks too going into overdrive at full throttle.i get by this by leaving it in drive til i reach the speed i want.

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I am also not positive but a GM technician may be able to permanently disable the torque converter lockout clutch.  This may set a code, not sure. 

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22 minutes ago, Imperial62 said:

I am also not positive but a GM technician may be able to permanently disable the torque converter lockout clutch.  This may set a code, not sure. 

 

I  installed a rocker switch out of sight under the dash so I can disable the converter with a flip of the switch. Most of my driving is on rural roads and I don't like the converter locking and unlocking all the time so I keep it disabled. When I do drive on the interstate I just flip the switch to the on position to allow the converter to lock at higher speeds. It will set a code E039 but no warning messages are displayed  on the IPC or CRT.

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5 hours ago, Imperial62 said:

Could it be the Lockout on the torque converter?   This solenoid activated (I think solenoid) lock locks in the engine to the transmission for a direct drive for improved gas mileage purposes.  It was introduced on most makes in the 80's and 90's.  Torque converters slip, which means more rpm and energy to run, less gas mileage.

 

The converter could be giving problems but I don't see how it would cause this problem when it shifted into 3rd gear the way he described it. He said  " engine revved up to as high as the screen would show ". That sounds like a situation where the 3rd gear clutch pack failed to lock up which was most likely caused by a loss of fluid pressure or something wrong in the valve body. JMHO

 

 

 

 

Edited by Ronnie (see edit history)

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On 12/1/2017 at 1:21 PM, 2seater said:

The other thing that may sound counterintuitive is an ignition misfire. This will show up under load, such as when it goes into high gear and the TCC locks up under moderate throttle. Take a close look at the ignition coil pack and the ICM module under the coils to see if there are signs of overheating such as soft or leaking potting material in the module.

my coil pack is leaking badly.do i want to buy new coil packs or do the swap to the other kind?

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11 hours ago, Ronnie said:

 

I  installed a rocker switch out of sight under the dash so I can disable the converter with a flip of the switch. Most of my driving is on rural roads and I don't like the converter locking and unlocking all the time so I keep it disabled. When I do drive on the interstate I just flip the switch to the on position to allow the converter to lock at higher speeds. It will set a code E039 but no warning messages are displayed  on the IPC or CRT.

Thanks Ronnie.  I agree with both of your points.  It is looking like a transmission rebuild for a permanent fix.

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3 hours ago, handmedownreatta said:

my coil pack is leaking badly.do i want to buy new coil packs or do the swap to the other kind?

The Delco coil pack and module does have demonstrably greater potential output than the Magnavox setup and is relatively inexpensive if sourced from a pick and pull, much more expensive if purchased new. Most likely the ICM below the coils is what is failing, and needs to be separated from the coils to confirm. It's really a personal choice. I still use the Magnavox style even with a slightly boosted engine and cannot speak directly to any actual improvement from personal experience. I do run a reduced spark plug gap of .050" which decreases the load on the coils.

 

Just my observation from watching others experience with the two systems is the coils fail more often with the Delco than the Magnavox but are replaceable individually. Conversely, the Magnavox has more failures of the ICM. Too bad they are not a mix and match. Most seem to report a smoother running engine when switching to the Delco.  

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I am not sure what the touch screen models show when in diagnostics but I am pretty sure it will indicate what gear it's in and if the TCC is being commanded to lock up or not while driving which may narrow the actual transmission mode where it acts up.

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2seater I can buy the Delco coil pack/ICM from a full service yard [the yard in Neenah out on Breezewood] then what Gibson's will sell me one for. Don't know why Gibson's [ a pick n pull] chooses to be more expensive but they are.

Edited by DAVES89 (see edit history)

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34 minutes ago, 2seater said:

The Delco coil pack and module does have demonstrably greater potential output than the Magnavox setup and is relatively inexpensive if sourced from a pick and pull, much more expensive if purchased new. Most likely the ICM below the coils is what is failing, and needs to be separated from the coils to confirm. It's really a personal choice. I still use the Magnavox style even with a slightly boosted engine and cannot speak directly to any actual improvement from personal experience. I do run a reduced spark plug gap of .050" which decreases the load on the coils.

 

Just my observation from watching others experience with the two systems is the coils fail more often with the Delco than the Magnavox but are replaceable individually. Conversely, the Magnavox has more failures of the ICM. Too bad they are not a mix and match. Most seem to report a smoother running engine when switching to the Delco.  

something is leaking yellow onto the radiator hose.i guess i need to look closer.

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Well a new tranny including install would be well over $1000 and that isn't an option for me at the moment. How much would just a rebuild be? Has anyone been through that process?

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7 hours ago, RetroJohnny said:

Well a new tranny including install would be well over $1000 and that isn't an option for me at the moment. How much would just a rebuild be? Has anyone been through that process?

 

The $1000 transmission installed must have been for a new-to-you used transmission. I've had two FWD transmissions rebuilt, both were Fords, and they were about $1800 for rebuilding the transmission and installing it. That price included replacing the torque converter and shift solenoids. I would expect the Reatta transmission to be about the same. Maybe a little cheaper since they don't have the electric shift solenoids.... unless you have a 1991 model.

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8 hours ago, RetroJohnny said:

Well a new tranny including install would be well over $1000 and that isn't an option for me at the moment. How much would just a rebuild be? Has anyone been through that process?

As a point of reference, I had the transmission rebuilt on my '92 Riviera (4T60E - same tranny as what's in a '91 Reatta) in 2014 at a cost of $2071 here in MA. 

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This suggestion is out of the box thinking, But had an issue with my car that seemed to be trans locking and causing driveabilty  issues

at Higher speeds, MAF was causing a De-fueling  issue . On my car it turned out to be a MAF Sensor. It costs nothing to test.

Just unplug the MAF and give it a drive. Car will be running on default ECM vaules when unplugged.

 Also ,The CRT will display gear changes an TC lockup if you are in Diag. ECM mode.

I have had 3 other GM front wheel car Transmission rebuilds donein the past. In my area a good shop I use cost between $1500 and $1800 with removal and reinstall.

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I have a post it note quote from a GM mechanice that moon lights nights and weekends rebuilding trannys. It is a 4 year old quote.

 Labor $350.00

 Kit $550.00

 Reinstall $300.00

 Total $1200.00

 I bought a used but rebuilt tranny for $350.00 when I did my engine swap on the Red. I paid my buddy $500.00 for his labor to do the swap [with me helping] but that also included swapping the engine as I had the engine rebuilt.

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