The Stovebolt Site Forums The Shop Area The HiPo Shop Do I REALLY need a transmission cooler?

As you folks know I am putting a 41 gmc coe cab on a 2001 chevy 3500 cutaway van frame, it has an 8.1 3ngine with a 4L80E transmission. I have mounted the engine behind the cab and I want to know if I really need a transmission cooler, as of right now my plan is to make it into a BIG pickup truck. No real plans for heavy towing or hauling. What do you think? Dave

Dave, If you have the tranny cooler from the chassis, I'd install it. I wouldn't want to take the chance of burning up the transmission.

Borg Warner made an air cooled transmission. It wasn't good.

Your radiator might have a transmission cooler. You just have to plumb it in.

Good thought, Gord. That's generally all that's needed. I think Dave was shopping for a radiator, a while back anyway.

The 4L80 does have some weakness in the overdrive drum/sprag section, heat is the enemy of automatics, I would plumb in the cooler if at all possible.

My issue is, do I use a single radiator with trans cooler in it or use two stand alone radiators. My issue is the distance between the engine/trans and the radiator at the front of 5he truck. Thoughts? Dave

Some people I know, call that a transmission warmer.

Either way, you're going to need to run the tranny cooler lines from the tranny, wherever you put it. The best place for a air to oil tranny cooler would be up front by or in front of the radiator in the airflow, but I suppose you could put it underneath, closer to the tranny than the radiator would be.
A tranny cooler (or transmission warmer as Mark says) in the radiator would be the most convenient thing to use as far as finding a place to mount things.

An OTW cooler in the radiator isn't a transmission warmer until the engine starts to overheat. Guys I knew who used to drag race Diesels with auto transmissions had temperature sensors in the transmission pan and would only get concerned if the temps got way over typical engine overheat temps, and that only happened after a few passes down the track. An OTW cooler would still cool the transmission, but would function as a warmer only if the radiator temp was warmer than the transmission as in first driving after completely warming the engine up.

A separate heat exchanger in front of the radiator will benefit from the cooling fan pulling air over the device, similar to the stock set-up.

Or a remote oil-to-air cooler with an electric fan. But yes, the stock setup with OTA cooler in front of the radiator would work well also.

Back when I was towing travel trailers on a regular basis, I would add a second A/C condenser in front of the tow vehicle's OEM radiator/condenser stack and install a high volume flex fan on the engine. I'd split the flow of the added cooler, running engine coolant through 2/3 of it, and transmission fluid through the other part. That setup increased both the engine cooling and the trans cooling. The extra trans cooler was plumbed in series with the built-in radiator cooler. Of course, that was way back in the dark ages when A/C condenser tubes were copper- - - - -it would be virtually impossible to do that with a modern aluminum condenser!
Jerry

Yes. slush boxes need to be cooled. If you didn't, it would eat itself very quickly.

In winter my 4L80E trans oil never sees 100 deg unless it gets over 40 deg. ambient. I installed a oversize cooler. Now I wonder if I should also use a thermostat. 4L80s do heat as soon as the TCC unlocks. I wasn't aware of the OD sprag heat issue.

The 4L80 is built heavier than the than the 4L60 but they both had similar issues, mostly in the overdrive section. I had a 2000 K3500, crew cab, dually, diesel, only had 150,000 miles on it when I had to have the tranny rebuilt, it was the overdrive section. That truck had factory coolers for oil, power steering/hydroboost, and two for the tranny.