I've always wondered that myself, my Jeep 5.9 with the 46re the Previous owner bypassed the main rad and went staight into the aux cooler he installed.. I wondered if this past winter we had made the temps too cold or not.

But i guess it didnt do anything to the temps that much. It got pretty cold in Virginia this winter too, around 10f for awhile. I felt the transmission lines going to the Aux cooler and the pan after only 5 minutes of driving and they were luke warm or body temp which is around 100f or so. After only 5 minutes id say it wasnt getting too cold, because after more time driving it will heat up more.

I made sure the check valve wasnt broken either, by unplugging the return line and turning the engine on for a split second. ATF gushed out like crazy.

I wish i had a thermostat in the oil tho so i know exactly what the temp is. I do know one thing tho, i wouldnt be running the line to the aux then the main radiator.. The transmission runs better at temps under 180f. If your running it through your main radiator last... which is only 1 line for the transmission part your basicly putting 200+ f atf back into your transmission, thats the whole point going Main rad, then AUX then tranny, to keep the temps below engine temperature.

Any transmission is suppose to be 40f over ambient air temp to work right. Towing is over 60-75 degree's. So if its 95f outside, and your towing the temp should never reach above 170-180f or then you have a cooling problem if you have an AUX cooler installed. An average day of say 80f not towing you should always be around 130-140 tops with an aux cooler.

 

Nah, radiator first, then aux. If you're worried about the aux cooler keeping the transmission too cold in winter, just throw a thermal bypass at it. Here's one source: http://www.summitracing.com/parts/DER-13011/

 

Why would you need to run it through the radiator? cold weather? How about the factory setup that doesnt use the radiator, just a factory trans cooler. No problems in cold weather that I've noticed.

 

There ain't such a setup from the factory.

 

Here it is, radiator removed for clarity!!!
I wanted to do the remote filter and check valve delete, but not sure how to connect back to the hard line. it is one of those fittings similar to the fuel rail disconnect. Factory radiator and tranny cooler. notice they are not connected. What gives?

 

not trying to thread jack or anything but quick question... i have a 95 1500 5.2L 203k miles on it my transmission went out on me so i had it in the shop they did the basic rebuild and rehaul on it, im really worried about it giving me problems again! so my question is what all do i need to buy to make the life on the transmission last longer and will it mess with my warranty on my transmission? and what im basicly asking is parts and websites i can order this stuff from or can i get it at my autozone or napa? thanks you guys just need a basic recap lol. oh and just to clarify i dont do anything hard on my truck it is my daily highway driver and only thing i haul are my dirt bikes.

 

go to www.summitracing.com find the derale deep pan, get a aux. trans cooler, a trans temp gauge, and a remote filter. other than that keep up on proper maint. with fluid/filter changes, and band adjustment and you will be set.

 

Guys,
FWIW - My truck has 135K on the original tranny towing a 16 foot trailer with all my toys (about 5500 lbs) and have had no problems with it. The only thing I did was add a drain plug to the pan. I Change the fluid every 20k miles with full synthetic. Never over heated and my check valve is still in place. I thought about all those upgrades but since it's been doing just fine with the FREQUENT fluid changes I decided not to mess with it. I'm the original owner.

Demoe