What is the maximum transmission temperature you guys are willing to tolerate when towing? My F150 runs at about 155 to 160 degrees under normal circumstances. I'll be towing about 5,550 pounds (new trailer) and am wondering what to expect for transmission temperatures. I have the towing package with the cooler. I'm curious, do any of you know whether the transmission cooler has a "thermostat" of sorts that keeps it in a normal operating range? I would think it could run too cool in winter otherwise.

 

Search function is your friend.

https://www.f150online.com/forums/sh...ht=tranny+temp

See reply #7 for two charts.

Keep it under 175 for longest life.

 

If yu tow in the summer you are not going to keep the temps under 175 pulling that weight. I pull A little bit more that that frequently during the camping season and my edge usually reads between 185 to 200 depending on the terrain. on the longest hill I have ever been on the temps went up to 207 for about 2 minutes. It was also 90 outside. There was a different chart on here somewhere about two weeks ago that had more realistic temps for towing.

 

I'll see 180* sustained for the most part in the heat of the summer. 210* has been as high as I've gotten mine on a good 6% grade in second gear before I realized the TC was not locked yet. Also see 210* while towing in stop and go traffic.

Once I'm able to get up to speed, the temps will go back down again and settle in @ 180*

I don't tow much in the winter, but in early spring, it'll go to 165* and up to 195*.

No thermostat, as such, on these coolers, but the stacked plate kind are supposed to 'flow' a little less until the fluid warms up and thins out a tad.

Running empty and very cold outside, my temp barely gets over the 100* mark. Takes a lot of stop and go traffic to get it to the first 'dash' on the gauge! This is with the stock cooler as well.

My temp is taken from the trans output line, just before it goes to the rad cooler up front. "Scan gauge" temps or "pan" temps might be different??

IMO, where I get my temp, I figure I'm getting the highest temp the fluid is at because it's already left the trans, so the TC has had it's time with it.. You would be amazed how fast the temp will rise when running the TC unlocked. I like to know this, so I can decide how to 'adjust' my driving style to get the TC to lock or do whatever it takes to keep the temp from going much higher then 210*. So far, that's MY peak "OK" temp when I know I'm working the trans. As long as it's not running that hot while I'm just cruising, I'm ok with it. My water temp has gotten to 210*, and that's towing in the heat of the summer as well, while going up that grade. It'll settle back to 195* when the speed is up and running in third.

Sounds like you are really doing your homework before taking your rig out for the first time! My first trip of the season is not until May! I wish I could go now! Let us know how it goes when you get the rig out on the road the first time!

Mitch

 

190's on the flat as high as 210 in the hills and mountains.

 

I towed 2000 miles pulling 7500 lbs from Dallas to Savannah and back a couple months ago. Highest temp I ever saw was 176. Outside temps never got over 75 though. I also kept it in 3rd gear and never went over 65. Actually the only time it got that high was when I put it in 4th just to see what would happen. As soon as the torque converter kicked in temps immed. went up. I shifted back down to 3rd and left it. Average temp was between 169-172.

This summer I know I'll see higher than 175 so I'm most likely going to install an aftermarket oil cooper.

 

Mitch, I think you are dead on about the torque converter lock. I'll bet transmission temps are a lot cooler in 3rd with torque converter lock than they would be in 4th without lock. We are going to be pulling about 3,000 miles in July from Minneapolis to Colorado so thanks for the information. The ScanGauge just gets its inputs from the OBDII so I guess it is whatever the engine management system is reading.

 

Does the torque converter ever lock in 2nd gear?

 

If I were towing, I'd do a tranny fluid replacement and use Amsoil ATF. Just a bit of an insurance policy - it may run just a bit cooler, and if it does get hot it won't break down as soon as conventional fluid.

 

I'd spend my money on a Mag Hytec Double deep pan. When I had a F-150 it droped my temps by a good 10 degrees or more. The key to good fluid life and stablility is capacity. If you can add 2 or 4 quarts over stock that is more fluid to stay at a steady temp. The more cool fluid you have the better.

 

Bob, yes, the TC will lock in second. I found that once the trans downshifts into second on it's own, keep your foot into the gas until you 'feel' it lock. The rpms will drop a couple hundred points as well.

Adjust your pedal to the speed you wish to maintain and keep an eye on the temps. For me, I like holding 50-55 mph and with my 3.55s that's right around 3000-3500 rpms. I don't have my foot to the floor either.. Maybe 1/2-3/4 at most. Steeper hills, might require it to be matted however!

Mitch

 

WOW, don't know what else to add guys. Great stuff. Don't remember who mentioned it, but what gear you lock the converter in is completely irrelevant just as long as you get it locked. Temps should hold around the same wether your locked up in second or third. But, the best comment of the thread so far is swapping over (completely, not just a pan drop & change) to Amsoil ATF. It may not drop your temps noticably, but you will definately not have to worry about burning up the fluid.

Good points about the Mag-Hytec pan...I want one. That also alone wont reduce temps, but as mentioned, definately aids the service life of the fluid with so much increased quantity. Increased quantity may lengthen the time it takes to warm up the temp, but that alone wont eliminate it. IMHO, swapping over to Amsoil ATF is a more cost effective mod than the pan alone and staying with some other fluid....but the pan is waay cool.

My temps are cooler than just about everything mentioned here but I have a tranny cooler off a 2000 F-250 LD...H-U-G-E difference.

 

I'm not completely clear on what you mean by completely change fluid versus pan drop and change. Can you help me understand exactly what you mean by that? This F150 is the first automatic I've had since 1974 so I'm not as well versed in automatics. Yeah, I'm a manual transmission die-hard; but found out a manual in a truck is fun but not great for towing in some instances. Gave up my beloved F150 5-speed because of towing.

 

A pan drop only gets about 1/3 of the fluid out. The rest of it is up in the valve body and in the torque converter, which has no drain plug. There are a couple good ways to get it all out, one of which is a flushing machine. Mark Kovalsky has an article on how to do it yourself without a machine, it involves disconnecting a cooler line and requires a helper.

 

Huh...that's weird cause it lowered my temps and that's the ONLY trans mod I had. Must have been a fulke for me and everyone else who uses them. Heck, even their diff cover alone drops temps a good bit and that doesn't have direct airflow compaired to the trans pan.