Transmission cooler install

[Matthew Cody]

So my last "upgrade" didn't get much love-luggage rack, but this is more of an essential upgrade. I installed a factory transmission cooler from a 89 Turbo TC on my 91 V6. The V6 cars were equipped with a very fragile automatic transmission known as the A604/Ultradrive which was plagued with issues from the beginning. I did all the external upgrades to help prolong it's life. The V6 cars used the small integrated transmission cooler built in the radiator, which I'm not a fan of at all. I bypassed it and plumbed in the factory large cooler to help keep the fluid nice and cool. It was direct bolt on, factory fit. I bought new cooler hoses, $8.00 at Autozone. 

[Hemi Dude]

You went from a ‘pop-fly’ OUT to a bases loaded ‘home-run’. A good modification especially in hot areas. The factory integrated cooler is actually meant to heat up the tranny fluid in cold climates. Think about living and driving around in a Minnesota blizzard. It is sort of similar to removing the thermostat from your engine. I run a 195 stat even here in AZ.

On my 3.0L Voyager, I run the coolers in series, first into the ambient air cooler then through the radiator cooler and back to the transmission.

I did a lot of cross country towing with that van, never a problem.

[Matthew Cody]

Thanks Hemi. It gets very hot here in Georgia, plus I live in the north part of the state with mountains and plenty of hills. My track record with A604 transmissions has been bad, I've had 3 fail on me, all in heavier minivans right around the same mileage, 130-140K, I should have at least another 90K out of this one hahaha. 

[Reaper1]

Yes, an auxiliary or external cooler for the A604 is pretty much MANDATORY in order for it to live. I'm actually surprised these cars didn't get one beyond the regular integrated one. 

 

I'm also a firm believer in oil coolers for turbo cars. 

[Hemi Dude]

It took many years to ‘perfect’ the 41TE/604/ Ultradrive transaxle. Now it has become the 62TE, a 6 speed used in most FWD vehicles by Chrysler.
I had a 2010 Chrysler T&C minivan. This was a great vehicle.

[Reaper1]

I heard a story from a guy that was around when the A604 was under development in the late 70's I think is what he told me. He said they had a transmission on a dyno and a whole room of computer equipment running it and at the time was told that eventually all of it would be in a car! I can imagine how hard that had to be to believe at the time. Anyway, the point is it took Chrysler almost 30 YEARS to get clutch to clutch electronically controlled and adaptive technology to actually work as intended (mostly). 

 

The challenge is in the way it figures out how to apply the clutches. It's a moving target. I bet a modern AI adaptive would make it almost perfect, but we had to get to that computing technology point. 

 

Another interesting note is that, just like the engine controls, Chrysler used a totally different strategy for transmission control (for better or worse). It's why there's basically NO aftermarket tuning support. By far the best shift strategy can be found in the Prowler, but I don't know of anyone that has been able to reflash a TCM with a Prowler code because it takes a VIN to do it, plus that was the 42LE...very similar to the 41TE, but because it has "slap shift", there's other integrated things that aren't on the original 41TE cars and it's not known whether it will actually work.

[Hemi Dude]

In the Beginning; No, in not the Bible, but the 604 as we first knew it. After they finally produced some that could be road tested, I heard that they sent a number of vehicles from Detroit on a test run to Los Angeles and back. There were somewhere like a dozen different vehicles, all with the 604.

When they left the plant, one of the vehicles had a transaxle failure before they got off the property. As they traveled, more and more failed, when they finally returned, all the drivers were packed into 3 or 4 vehicles, the rest had broken down along the way and left at various dealers for repair when parts were available. It was not the electronics that failed but hard part internal components that were not up to the job.

I was a Torqueflite rebuilder since the 60's at the various shops that I had worked at, but left Dealership life in May of '88 to open my own shop.

I'm glad I never had to rebuild a 604/41TE or anything that resembled it. When I had one of them to rebuild, I sent it to a friend who did them at the dealership and he did them privately for me. Over the following years, he would buy low mile, busted transaxles from wrecked PT Cruisers and swap all the PT guts into a TC transaxle case. Those components had all the upgrades and we had no further trouble with those TCs.

[ghostymosty]

My friend who was a transmission rebuilder for the local Chrysler dealer informed me that most of the early trans failures could be attributed to top offs done by people who used non Mopar fluid of the incorrect type. This would usually destroy these transmissions in a short time. When he rebuilt these transmissions he would educate the owners about the correct fluid and do the wire snip on the very early transmission controllers, he never had one of these come back to him with problems. He would also never use any aftermarket fluid in these transmissions. 

The original owner of my triple black TC was very concerned about reports of early transmission failures so had my friend put a later model crate transmission in the TC (and the wire snip). I never once had a problem with that transmission.

 

Edited January 18, 2021 by ghostymosty (see edit history)

[Matthew Cody]

I've noticed that many early A604 cars have Mopar reman transmissions in it, including a black V6 TC I used to service. Same with a 91 Acclaim and 94 Voyager I bought used, both had pretty gray remans in them. Back when my folks bought a brand new 93 Plymouth Grand Voyager, the A604 transmission failed in the warranty period and due to the high volume of failures, we had a loaner car for over a month while they waited for a replacement transmission. I remember the service manager pointing to a row of minivans, explaining that they were all waiting for new transmissions. I did all the external upgrades on my TCs original unit; updated sensors, solenoid pack, TCM, fluid and filter, use only Mopar filters!, I had an aftermarket one fail on my 90 Plymouth Acclaim and ruined the transmission $1,400 lesson learned. 

Edited January 19, 2021 by Matthew Cody (see edit history)

[Reaper1]

To add to Hemi's story on the test drive, I also heard that not only did one fail before it got off the property, but that 3 had failed before they got out of Detroit! 

 

As for the guts, I know there's been updates over time and I know the overdrive snap ring is a common failure. I also know that later units can hold a LOT of power (NOT overdrive!!). There were a couple used in Neon SRT-4 cars using an aftermarket controller (no longer available). Those engines were in the 800hp range. The review was that being able to tune the transmission was a quantum leap over the old A413. Unfortunately there were no "adaptives" incorporated with this controller, so it was a race-only deal, and was really expensive. 

 

Yes, using the wrong fluid was the cause of a lot of early failures, but also, the software that runs the thing was also an issue. It was VERY intolerant of even small discrepancies that were not truly detrimental to the operation of the unit. 

 

As for the reliability...I had a buddy that worked at a dealership in the early 00's...they had something like 5 reman units ready to go in the parts department at all times! And they didn't sit there long...one of their personal vans went through 3 before they got a good one.

 

My personal experience is mixed. While I think it does have potential and in its final form is a fairly decent unit, it isn't the right "tool" for the driving I like to do. I kinda broke a few...

[Hemi Dude]

4 hours ago, Reaper1 said:

To add to Hemi's story on the test drive, I also heard that not only did one fail before it got off the property, but that 3 had failed before they got out of Detroit! 

 

"It isn't the right "tool" for the driving I like to do. I kinda broke a few...

Although in a way I really liked the 2010 T&C Minivan I had for a short time, it was mainly for the reason that I wasn't in control of the operation of that vehicle that I sold it less than a year after buying it. I have the A470 behind the 3.0L in my 85 Voyager and a 555 5-speed in my TC which I like driving the most. I guess I am just old-fashioned and want to do more of the driving. I'm glad to say I will NEVER own an electric car or a self driving one.

[Reaper1]

I don't mind electric cars. Instant torque, quiet, vibration free operation, very limited amount of upkeep...I'm game! As for self-driving, I can write a pretty long article on my thoughts on that, but TL:DR version: the technology is NOT ready because the infrastructure is NOT ready. 

[ghostymosty]

I like my electric Leaf, two plus years of ownership and I've put wiper blades and two tires on it, but it is uninspiring to drive unless I count the great torque from a standstill that can put me back in the seat unless I have the limiter engaged (eco mode). Just went from 10 bars to 9 bars and still have a 70 mile range. Hence the limit on looking for a TC only within 30 miles of me! Just retired from my job and might want to go farther than the range so a gas powered vehicle is in my future with the electric for store trips. And if you haven't tried a Tesla S in ludicrous mode then you don't know what driving really is!

Edited January 21, 2021 by ghostymosty
Added tesla comment (see edit history)

[75GL1000]

On 1/18/2021 at 12:26 PM, Hemi Dude said:

You went from a ‘pop-fly’ OUT to a bases loaded ‘home-run’. A good modification especially in hot areas. The factory integrated cooler is actually meant to heat up the tranny fluid in cold climates. Think about living and driving around in a Minnesota blizzard. It is sort of similar to removing the thermostat from your engine. I run a 195 stat even here in AZ.

On my 3.0L Voyager, I run the coolers in series, first into the ambient air cooler then through the radiator cooler and back to the transmission.

I did a lot of cross country towing with that van, never a problem.

Going to add a ambient air cooler to my trans, but was thinking thru the radiator cooler first then ambient air cooler then return to the transmission.  The return is on the top of the radiator cooler isn't it?  Any thoughts?

[Hemi Dude]

My personal thoughts regarding transmission coolers are these. If the transmission would be worked hard such as pulling a trailer or a car dolly for long distances, a cooler would be helpful in keeping the trans fluid temperatures under control.

Also where people live in very cold climates, a cooler is actually helpful in warming up the trans fluid to operating temperature.

Beyond that, our TCs really don’t need the cooler. The transaxle itself is really not affected by general  driving condition temperatures. Their failures were and are internal seal and component design failures. My transmission builder use to acquire ‘broken case’ automatics from PT Cruisers and exchange all the internals from them into earlier 604/41TE cases.

[Plumbinguy]

Interesting that there have been so much trouble with these trans. I've own two 94 Lebarons loved the drive trains in those cars. Never had a mechanical problem with either one, neither one ever saw a mechanic. I especially liked the trans when I took it out of overdrive. Cars roted out from under me. That was my only complaint with those cars.

[Matthew Cody]

I've had 4 A604 transmission fail on me, albeit in heavier minivans. I live in a very hot and hilly area where the transmission is constantly shifting and and getting hot. Since my car has the original transmission in it, I'm trying to get the most out of it. If it fails, the car simply isn't worth putting a new one in and would be sold for parts. 

[Hemi Dude]

5 hours ago, Plumbinguy said:

Interesting that there have been so much trouble with these trans. I've own two 94 Lebarons loved the drive trains in those cars. Never had a mechanical problem with either one, neither one ever saw a mechanic. I especially liked the trans when I took it out of overdrive. Cars roted out from under me. That was my only complaint with those cars.

To address your comments, 1989 was the first year for the “Ultradrive” A604. All the 1990 & 1991 V6 TCs got the earliest built units. That was a major problem for these cars. By 94 many improvements had been made.

Having lived in New Jersey, I’m rather familiar with cars rotting out, I was a line mechanic at several dealerships there.