3800Pro Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
3,571 Posts
Discussion Starter · #1 ·
Only if you're planning to pull a trailer through the mountains. Otherwise, we recommend against it on vehicles with the 3800 FWD/4T65E drivetrain.

We have dissected more of these trannies than anyone else in the performance aftermarket, and we have yet to see a single heat-related failure. Hard parts break in these trannies, and these failures will not be prevented by a tranny cooler.

Tranny coolers add unnecessary weight and opportunities for fittings to leak. A leaking fitting can let your tranny run dry in minutes and ruin it far faster than a little heat ever could.

Our trannies are cooled by the same radiator used to cool the engine. So running a colder engine thermostat will make both your engine and your tranny run cooler.

Scott
 

·
Registered
Joined
·
242 Posts
not to be a biznitch, but my car always shifts sloppier when its very hot outside say 90-100deg or sitting in traffic, the trans isnt as firm, thats for a stock tranny though of course that was raced a lot, im sure it differs car to car, mine would run like garbage without it in hot azz weather.... can it hurt anything other than maybe leaking?
 

·
Registered
Joined
·
44 Posts
Mine will slip at 50-75% throttle only when the engine is hot. The regular (not a high engine load) shifts are also much sloppier when the car is hot compared to cold. I know this is mostly becuase my tranny is wearing out, but again it doesnt ever slip when the car is cold.

Also, the strange thing is, while it will slip quite severly (like 2.5 seconds to shift) at 75% throttle, it wont slip at WOT. When Perf. shift is on it never slips. Tranny has 90,000 miles. Why is this?
 

·
Registered
Joined
·
14 Posts
I ran a 160 t-stat and in traffic with 90 degree heat I never saw tranny temps over 180 degrees. You also need a fan switch or pcm to turn the fans on sooner or your coolant temps will shoot up in traffic causing your tranny temps to rise as well. Whenver I saw engine temps getting to about 180 I turned on my fan switch.
 

·
Registered
Joined
·
19 Posts
Mr. INTENSE said:
Only if you're planning to pull a trailer through the mountains. Otherwise, we recommend against it on vehicles with the 3800 FWD/4T65E drivetrain.

We have dissected more of these trannies than anyone else in the performance aftermarket, and we have yet to see a single heat-related failure. Hard parts break in these trannies, and these failures will not be prevented by a tranny cooler.

Tranny coolers add unnecessary weight and opportunities for fittings to leak. A leaking fitting can let your tranny run dry in minutes and ruin it far faster than a little heat ever could.

Our trannies are cooled by the same radiator used to cool the engine. So running a colder engine thermostat will make both your engine and your tranny run cooler.

Scott
I was thinking about putting a tranny cooler, but what Scott said above makes alot of sense. A reprogramed PCM will turn the fans sooner then the stock one, and if your running 160* stat, then your engine and tranny should run way cooler then a stock aplication or with some mods and no PCM.
 

·
Registered
Joined
·
11 Posts
toefungus said:
I ran a 160 t-stat and in traffic with 90 degree heat I never saw tranny temps over 180 degrees. You also need a fan switch or pcm to turn the fans on sooner or your coolant temps will shoot up in traffic causing your tranny temps to rise as well. Whenver I saw engine temps getting to about 180 I turned on my fan switch.
I am going to assume you use your engine temp gauge for tranny temp or do you have a seperated tranny gauge. If you have a seperate tranny temp gauge would you mind telling me how you mounted it and where did you place the sensor.

I ordered my tranny cooler kit on 10/1 and it arrived 10/7. If I would have waited one more week and read this post I probably would not have bought a tranny cooler. Hindsight is always 20/20. :(
 

·
Registered
Joined
·
72 Posts
VT Regal said:
Mine will slip at 50-75% throttle only when the engine is hot. The regular (not a high engine load) shifts are also much sloppier when the car is hot compared to cold. I know this is mostly becuase my tranny is wearing out, but again it doesnt ever slip when the car is cold.

Also, the strange thing is, while it will slip quite severly (like 2.5 seconds to shift) at 75% throttle, it wont slip at WOT. When Perf. shift is on it never slips. Tranny has 90,000 miles. Why is this?
I believe perf shift will change the shift points and increase the line pressure. Someone correct me if I'm wrong. It really sounds like you have transmission problems, though. Valve body or PC solenoid come to mind. With the slipping happening, you are likely to be causing additional damage to clutches and maybe bands and drums. Start saving a rebuild fund if you haven't already.
 

·
Registered
Joined
·
314 Posts
ive seen more trannies blow up because a line going to the tranny cooler or the tranny cooler itself blows, and dumps fluid out all over. don't use one unless your pulling a trailer through the mountains.... what scott said :)
 

·
Vendor
Joined
·
260 Posts
I'm going to disagree with you on this one. The hotter the transmission is, the more the clutches slip. The more the clutches slip the hotter the transmission gets. Since slippage causes more heat this is a slippery slope. I have seen plenty of soft part failures on these transmissions. I think that the majority of people that come to visit your company have modded their car and have destroyed a hard part because they're putting too much power through the car. The hard parts in a high torque motor will usually be the first thing to go and they are certainly the weak points in this trans (pump shaft, Input shaft, etc). I wouldn't even consider putting one of your transmissions in unless I was sticking in a 25 - 30k stacked plate cooler at the same time.

As far as failures from fittings... Well there's no excuse for a half ass job. If you can't find a mechanic that can install a fitting worth a damn then you need to go lock yourself in the basement with a work manual. :) A properly installed fitting will last just as long as stock.

220 degree transmission temps are not acceptable in any other transmission and they shouldn't be acceptable on the 4T65E either.

Our trannies are cooled by the same radiator used to cool the engine. So running a colder engine thermostat will make both your engine and your tranny run cooler.
This is a heat exchanger (to engine coolant) more than it is a cooler. It is designed to match the engine's temperature. If the system is kept seperate from the stock radiator you'll have a transmission that has temps of 150 - 160 degrees and an engine that has temps of 165 - 195 degrees. With the stock cooler you have an engine sitting at 180 degrees and your transmission is usually +/- 10 degrees from that. This is less than ideal. Your average stacked plate cooler weighs in at about 2 lbs. I'm not that desperate for weight savings... yet.;) An aftermarket cooler (if installed correctly) uses the same style fittings as the stock cooler you already use. For this reason, an aftermarket cooler is no more dangerous than a stock cooler.
 

·
Registered
Joined
·
11 Posts
which tube?

mtsman said:
I ordered my tranny cooler kit on 10/1 and it arrived 10/7. If I would have waited one more week and read this post I probably would not have bought a tranny cooler. Hindsight is always 20/20. :(
Well I installed the cooler anyhow.

Has anyone addressed this thought :

Now, does it matter wether the auxiliary cooler I installed gets tranny fluid before the so called tranny cooler in with the radiator (or heat exchanger) or should it get tranny fluid after it. My guess would be to run the aux. cooler after the tranny cooler within the radiator (or heat exchanger). Who knows which direction the fluid flows? The fittings are located in different spots in the tranny housing. Which line or fitting flows fluid back from radiator (or heat exchanger)?

Did I explain that clearly?
 
1 - 11 of 11 Posts
Top