Ok this is gonna be a little bit of a long post, but I want to give all the info I have on whats going on so far.

I have a 87 Cutlass street car, Full interior and weight. 5.3 sbe S475 96mm 1.10 A/R on pump gas, 9" 3.25 gear. Guessing 3300-3600lbs

I just put a 4l80 in controlled by a microsquirt. Jakes stage 3 rebuild kit, Jakes D3 transbrake valve-body, and Jakes triple disc Convertor (around 3500 stall). Running Dex 3 fluid as recommended by Jakes

I have a Derale double stack Transmission cooler -6an lines with fan set in under the trunk floor with the fan pulling thru the cooler towards the ground with about 2 1/2 inches of space between the cooler and floor board. The cooler has a T-stat of 160 degrees.

I drove the car for the fist time with the 80 this past Saturday. 60 degree day. I know nothing about tuning this transmission yet. So I was driving around for about 40 minutes, just around town style driving getting on it every once in awhile. I was seeing temp just over 200 degrees on the computer reading the factory temp sensor in the trans. When it was just around 190 degrees I got out and checked the cooler and the fan was not running. I used a temp gun on the lines and they should to be around 155 degrees. So when I got back to my shop the temp was reading around 200, I temp gunned the line again and showed around 164 and the fan was on, the trans pan showed around 160's as well.

All this driving was pretty much in 3rd and 4th gear unlocked.

So I rewired the fan to be controlled by the Trans control computer to turn the fan on at 120 degrees. Took the car back out for a ride. Still seeing temps of 200 degrees, but the inlet of the cooler is warm and the outlet cold.

Last night I changed some settings around to lock the convertor up in 3rd around 30mph and also locked up in 4th. It was much cooler out last night. Somewhere around 30 degree air temps. I only got to drive the car for a short time. and the temp got up to 140 degrees.

So Do you think I'm getting a false reading from the internal temp sensor? Around ambient the temp sensor is inline with the Air/coolant temp.

Do you think with the cooler under the car the way it is, that I should reverse the fan direction to blow air thru the cooler?

Maybe a even bigger cooler than I'm running now or different type?

I really don't want to move the cooler up front, as the intercooler and turbo setup have taken up a lot of room. But I guess as a last resort I will do that.

 

I'm around 145/150's around town ion 3rd/4th unlocked on a 50 degree day.
On the Hi way it will go in the hi 130's with it locked.
B&M 70274 cooler only in front of rad, 4400 9.5" triple disc
4.30's with a 28" DR's

 

Seems that the internal temp sensor is close to your infrared temp gun reading.

How long are your cooling lines and what size and material are they.
Sounds like a low fluid flow rate.

 

This is what he's got.
I also have the -6 ptfe braided lines to the cooler.
I think it's just where he has it mounted.

"I have a Derale double stack Transmission cooler -6an lines with fan set in under the trunk floor with the fan pulling thru the cooler towards the ground with about 2 1/2 inches of space between the cooler and floor board. The cooler has a T-stat of 160 degrees."

 

Just to update. I tilted the cooler and had little to no effect. Around town under 35 mph was in the 160 range. Get on the highway at 70 mph goes up to 178. Got a 11x11 B&M cooler. Gonna mount it up front and see what happens next.

 

I think your going to see an improvement with it up in the air flo.

 

I too see 200 degree temps out of my 4l80. Ptc 3400 3.08 rear, Bm 11x13 cooler with 8" fan mounted under the bed of the truck. -6 lines total of 20 feet long. BM extra deep trans pan as well. Always hot. I just ordered a monster derale cooler with 10" fan im going to try that if that dont work ill run2 of them