Well now I know how effective the factory installed engine heat exchanger is.

In addition to the factory installed engine heat exchanger and the small cooler up front, I had previously installed the heavy duty, fan cooled, transmission cooler under the bed. I always felt as if the under bed cooler was chilling the fluid, just so the engine heat exchanger could heat it back up again. Kinda seemed like a waste of time. Soooo, yesterday, I disconnected the engine heat exchanger leaving the under bed cooler and the one up front to do all the work.

Reason I did this is because I thought I had heard on this forum, that the tranny temperatures should go down. Well mine didn't. They went up.

It used to be that cruising solo, on the Interstate at 65mph I would run about 150-160F. Now I'm running 195F. Round town with the stop and go traffic, I used to run 190-200F. Now I'm 210-220F. I hate to think what it would be like pulling the trailer. Since the only reason I did this was to pull my temps down below 220F when towing, and I can hardly do that without towing now, I consider my experiment a disaster.

Today I put it back as it was, and the temps came back down.

Has anyone else tried this? and what was your experience?

John

 

ive read about several people attempting it. that stock heat exchanger does alot of work, just use the aux cooler as a suppliment. even if you had one that could drag the temps down enough to be heated by the engine coolant, you want to keep the atf around 160-180F, and the heat exchanger will heat the fluid on cooler days. well if you put the aux cooler between the tranny and the heat exchanger anyway... my aux cooler brought the normal crusing temps down probably 5-10F (fan off under the bed) then when i get in heavy traffic for long periods of time it holds it around 200-210F with the fan on...

 

HI,

It's interesting that you should say what you did about tranny temps....I had added an aux cooler to my truck ( a small plate type cooler in front of the Ac condenser) BUT the shop disconnected and removed the small cooler (not the air to water one BUT the small one in the upper right side of the truck when viewed from the front....they said they had to in order to get all the trans lines to the new cooler)) when they installed the new one....I was paranoid about losing the small air to air factory cooler, so I ordered a larhe tru cool H7B from DTT to replace the small new air to air cooler....As fate would have it I towed about 10K and the next day my tranny was dead....(trans was rebuilt 25K ago by previous owner...trans shop owner said heat caused a seal to blow)....Anyways I had a shop rebuild the tranny and they eliminated the factory water at air cooler and took out the small cooler I had added and put in a large Tru Cool oil coler (H7B) it is rated at 29200 BTU rating.....Their smaller 20000 BTU rated unit is for a 22000 GVW.....I am not sure what this 29200 BTU cooler is rated for but I'm sure alot....I am not sure what my trans temps are at (I am installing the guages this week for sure)....

I am curious....what size / make cooler did you use?.....Currently I have do not have the factory air to air cooler OR the fatory water to air cooler....Just the Tru Cool H7B cooler and a B7M Finned alum Trans pan (+2) quarts I think......I hope the H7b in front is enough but I ordered another one today to mount under the bed with a fan...I figure this may be gross overkill but I am not losing a tranny to heat again!

Also just curious but I thought about adding a large hydraulic resovour like heavy equipment uses....increase the trans fluid by several gallons....has anybody here done that?....I figure if it;s good for heavy equipment it should be good for our trucks too!....Any thoughts on this?

Andrew

I'll try to let you guys know wht temps are when I hook up the guage (pan was tapped by the trans shop and the sender is already in...I just have to drill a hole and hook power and wire to the sender.

Anybody else use the setup I now have for better or worse?

Andrew

 

I have a MagHytek Double Deep pan with both stock coolers. Cruising solo I see about 160*-170*. Towing the fiver it runs 180*-190*. Up a long grade it will go up to 210*-220*.

I haven't been able to figure out what affects what. On the long grades in Colorado I'll run 25# boost and 1150* EGT for 15 miles or more. Especially up the west side of Vail Pass. This eventually thermally soaks the engine and I begin to see the water temp creep past the "normal" range. I never take it above the top line on the gauge. So I think I could be heating up the tranmission fluid with high water temps. Or maybe I'm heating the water with high transmission temps? I've never known for sure. So...I've always felt that my transmission temps pretty closely match my water temps due to the transmission fluid/water heat exchanger.

At any rate, I do think the double deep pan makes a pretty large difference. It's 6 Qts. over stock. When I changed my fluid last, I believe it was a total of 16 Qts. including draining the torque converter.

 

I would bet that your tranny is heating up the engine, unless your running really high egts.

Tuckerdee, do you know a good shop to get a rebuild from here locally?

 

I thought I had some transmission troubles a few months back, but it turned out to be just that the TV cable had come off. Anyway...I talked with a few shops back then. I called ATS, and they have some fabulous products for 2nd Gen trannies with full lock up converters. But they really didn't seem very interested in looking at mine. I also contact a guy named Bob Behrens at Performance Diesel up in Greeley. He's the most local DTT rep and installer. He was very willing to talk with me about all the options, costs, etc., but never called me back. I think he has all the work he needs and maybe more. I'm sure he would be fine to work with if I had re-contacted him and got the ball rolling a little faster.

I don't know of anybody that will work on the Getrag. If you need work on the Getrag, have you considered upgrading to the NV4500? I found a couple of places that sell kits for the upgrades.

 

No, I'm working on by brother in laws, same year but with the auto, its on its way out i'm sure, so were just looking for a place to take the trans to and have them go through it and get a good torque converter.

I have a spare getrag, needs a input shaft gear though and probably some other things, and i'm always looking for a nv4500.

 

truckerdee, where are you getting your tranny temp reading?

 

The sender is in the pan. The MayHytek pan comes with a port already drilled and threaded.

 

Sorry to not reply before now, but I've been out of town for the last week. The cooler I installed is from Summit Racing, Perma-cool PRM-12318. It has 1/2" lines, measures 10-1/2" X 21" long X 4" deep. With a 1250CFM fan.

I had thought of adding the Mag HyTech (spelling?) pan, but I thought that might just delay the inevitable, rather than fix the problem.

Anyway, now I know that didn't work, I'm going to remove the bypass for front tranny cooler that the factory in their infinite wisdom installed on the 89-93s.

John H

 

HI John and all,

Just to let you guys know I did finally get the guages installed!!....My tranny seems to run about 140 degrees w/ the ac on and in high 80's low 90's outside temps running empty or with about 800 lbs in the bed.......The highest I have seen the guage was while I was sitting at the landfill waiting to unload (probably about 7 minutes sitting....The pan temp crept all the way to 170 (I was idling in neutral w/ the park brake on and ac running).....So far, if anything the trans may be running a little on the cool side.....I haven't tried towing anything yet but I will probably do so shortly....I am planning on adding a second Tru Cool H7B cooler (it is actually their 1/2 inch engine oil cooler rated at about 29000 BTU heat removal)....and having a fan setup like the origonal factory type setup....IT may take me awhile to do becauuse I work so much nut I'll try to report the results then....So far it seems as tho this setup will allow me to run without the factory cooling.....

Andrew

PS - BTW maybe mounting the cooler in front of the radiator and ac condser would take care of any possible cooling problems.....my trans temps drop alot when just driving slowly....