Will another auxiliary cooler increase line pressure and slow the ATF flow?

JCByrd24 · Jul 6, 2014

I'm not an expert but have got to think the fact your only going 10 MPH is part of the problem. A fan would certainly help in that situation, probably way more than typically reported because usually trans temp issues are at speed with some air flow through the grille to do cooling. Also, 2000 rpm may be max torque but is not likely going to be best for the tranny. More RPM will give you more fluid flow and more air flow due to higher speed, and should lower temps.

JJZ 109 · Jul 7, 2014

Blane said:
Thanks for all the replies guys.

Mark replied on the Ford Forum with some good information.

He generally does. I have an Aeroforce Interceptor gauge on my 1997 F Super Duty (F450) that reads information available via the OBD II port. I recently reported on the Dieselstop forum that I'd seen a transmission temp of 223 when pulling a 5200 pound loaded trailer up a short, steep hill. I asked what range the trans temp should be in. Here's Mark's reply:
"You can go as high as 220F all day long with no problems. You can go as high as 250F for no more than a half hour at a time. If the trans does get hot DO NOT SHUT THE ENGINE OFF! Idle or fast idle in park or neutral to cool it down."

BWSwede · Jul 7, 2014

I guess I mistakenly thought that the faster I ran the engine with the torque converter not locked the more heat I would generate. From JC's comment it sounds like I could benefit from pushing the engine a little harder and getting the rpm's up.

Good to know about the temps as reported by Mark K. Todd's reply put me a little at ease with the temperatures I was reading. I once asked that question about how to cool down a tranny and the replies I got from one of the popular forums I read was to shut the engine off. This didn't make sense to me and when I questioned it the mob mentality of the thread took over and questioned my intelligence. When my tranny gets this hot I have not been immediately shutting down the truck due to the possibility of cooking the oil in the turbo. It now sounds like I should let it run even longer to cool the tranny down.

Thank's for the input guys.

CJONE · Jul 7, 2014

Is the cooler in the radiator bypassed by chance? If it is hook it back up, the main heat removal comes from this cooler. Water is way more efficient than air in removing heat. Anyway I have a 01 with a v10 cooler and have no issues with heat pulling anywhere from 18k to 24k, I think 200deg is the highest I have seen in 100deg temps. JC is correct the higher the RPM's the less slip in the converter in 1st. I can't comment on the lube issue [if there is one] with the first gear lockup but the program that is written for heavy tow for me locks the converter between the first/second gear shift under heavy acceleration. Brian at BTS trannys could answer that question easily. It would be worth a call to him. You will have no heating issues with the converter locked and both coolers hooked up.

F3506 · Jul 7, 2014

Installing a Magnafine filter is fine. That's actually what Ford does on anything they rebuild. I don't know enough about the transmission since I have always bought a stick shift and never had to worry about torque converters, but to me it sounds like if you can't lock the torque converter in 1st gear due to inadequate fluid movement, then that may be the source of the problem.

If I were you I'd start checking to see how much more fluid is flowing in 2nd gear and see if you could possibly make the same run a t a lower rpm in 2nd gear. Especially if locking the torque converter is an option then.

Of course if the temps are in the safe range for the short trip, it may be just worrying about nothing.

handirifle · Jul 8, 2014

I would imagine your transmission had to be rebuilt because of the extreme loads it's pulling constantly. Did it get built with upgraded parts, ie clutch packs etc, like those meant for high horsepower engines? If you're pulling near max weight a lot, the transmission really isn't built to stand up to that . Just my .02. In my mind I'd go for the added fan as an extra bit of insurance.

CJONE · Jul 8, 2014

Blane, just a FYI. I hauled 3 loads of gravel last night 4-5yd loads at between 13000-15000lbs + the trailer weight of 4500lbs in 85 deg heat with the AC on and the trans temp never went above 190. 20 miles loaded one way with a hill at the end that had to be in 4wd or I could not make it. The temp climbed from 160-170 to just below 190 because of the hill and maneuvering to dump the loads as I would expect it to. Anyway hope this helps. CJ

Oliver1655 · Jul 8, 2014

You mentioned the filter you added was between the tranny & the cooler. I hope since you were concerned with material in the coolers you meant after the coolers & before the fluid re-entered the transmission.

Several good ideas:
- Oil thru radiator cooler then secondary cooler on to filter then transmission.
- Aux fan in front of coolers.
- Keep rpm's up to increase air movements thru the coolers / radiator.

BWSwede · Jul 8, 2014

Great feedback from you all, thank you.

I have not bypassed the cooler in the radiator. Right now all the cooling system is stock. I'll have to look into the fist/second gear lockup if I still have a cooling issue after replacing my stock air/oil cooler with a 26 row cooler from a 6.0 PSD. I never have a cooling issue on the highway. The hottest it ever got was going over the 4000' pass between Oregon and California. Pulling 12,500 pounds up 6% it only got to 195 degrees. Granted when I did this it was about 35 degrees out.

F3506 - I don't think there is a fluid flow problem causing the ability to not lock the TC in first gear, my take is that the pump the manufacturer put in the vehicle does not flow enough ATF to allow the safe lockup of the TC in first gear so the computer doesn't let it happen. If I am wrong someone please correct my understanding.

Handirifle - Yes, when it was rebuilt I had a low stall, "RV" TC put in made for diesel engines that pull heavy loads. They also put in heavy duty clutches to handle the load that I told them I pull. I am going to try the larger cooler first, if I still have a problem, and there is room, I'll look to install a fan.

CJONE - I hope to attain the temps you are getting when I switch out my cooler. Everything is basically fine until I get to the hill where I live. It is a 600' climb at a much steeper grade than I ever encounter on the interstates. I am guessing it might be a 10% grade. The truck slows way down when I hit this hill.

Thanks again guys. I am picking up the new cooler today and hope to install it this weekend.

Blane