Auto Trans Temps While Towing

[EK2_T/A]

I have a 1998. 5 24 valve with automatic trans and tow an enclosed car trailer with a gvw of about 8,000 pounds. I have always been told not to tow in overdrive as this will fry the trans. After installing the trans temp gauge, I towed in overdrive on the highway (60 to 65 mph, outside temp in the 80's) and the trans temp stays around 150. My sending unit is mounted in that line from the trans to the cooler. Is towing at this temp a problem or is it somthing else that will trash the trans if I tow in overdrive? Any replys will be very helpful. Thanks

 

[Batman]

EK2_T/A

I just towed my 10,500 lb 5er in New Hampshire 2 weeks ago, read my sig to see what I have. My guage read around 150 for the hole trip except in stop and go, then it went to around 180.

So your temp sounds good to me.

HTH

 

[Fireman Dave]

Mike,



I see similar temps to yours. I see temps between 170-200 sometimes in stop and go traffic. As long as the TC stays locked up, I stay nice and cool. I did see 240-250 briefly when towing up a mountain in 2nd gear in CA (stuck behind slower traffic with no options to pass). Appears to be no harm done - fluid looks, smells, and tastes just fine after that! My sender is also in the cooler line. This is where we'll always see the hottest temps. Pan senders will show cooler. Personally, I always tow with OD off. It's a better RPM with my gear ratio, keeps the EGTs lower, and I believe it's better for the transmission (1:1 ratio in 3rd gear). Just my . 02 cents.



On a separate note, I invite you to be part of a local unofficial chapter we have going. There's almost 40 of us from mostly WI but also IL, IA, and MN that get together from time to time. No dues, just good, clean fun! I'd be happy to add you to our email list to keep you up to date on our activities. Let me know if you want to be included.



I also noticed your fine Mopar pedigree. I'll be down at Grant Park in So. Milwaukee this Sat. for a car show and a reunion of the WI Mopar Muscle Club. If you want to drop by - or if you're already planning on it - email me and maybe we can hook up.



Dave

 

[chuck3]

Tow in OD

I tow in OD a lot Ive had no proplems, I do try and keep the rpms up around 1800 or above. Temp runs about the same as yours.

 

[Extreme1]

That reference is to the early transmissions...

Back in '94-95. They have been fixed. I know, mine died from that and I had a new one installed in Jan of '98 that had all the updates.

 

[Dieselnerd]

As I recall, the '94 and some (or all?) '95's didn't have enough fluid going to the OD gears and they ran so hot while towing that they would literally burn the teeth off. Somewhere between '95 and '96 that was changed so that the gears got enough lubricant. They also changed the angle of the OD gear teeth. Those gears were one of the things Dave Goerend checked when he installed my mods to ensure they were the newer style and he explained that the earlier ones were sometimes a problem. My temps at the hot line going to the cooler run about 150 with TC locked and as much as 200 when parking. City driving runs about 175 with stop and go.

 

[EK2_T/A]

Thanks for all of the replys guys. It is great to have a resource like this. Fireman Dave. I will be in touch. Thanks again.

 

[Fred Swanson]

EK2_T/A,
Keep the RPMs' above 1700, and the temps below 260-275 (on the cooler line), that's when you're headed for trouble.

So do you haul the six-pak around alot? Show or race?

 

[David Pendleton]

I too have wondered about towing in overdrive. I tow a 23' Boston Whaler @ ~6,000lbs and I never tow in overdrive for fear of destroying my transmission.



What about these rumors that the transmission cooler will not operate properly at low RPM's?



I've got an '01 with Auto with the 3. 55 rear end.



Thanks.

 

[amsoilman]

EK2,

I think your temp is OK! I have a 94, and I have never seen temps above 200 ever, and that was in the summer at 100 plus outside. My sender is in the pan, and I do use a synthetic ATF as well. I have pulled in overdrive, but if the hill gets very steep, I drop it into 3rd, but lock the TCC.



Wayne

amsoilman

 

[barryg41]

I pulled across oklahoma during the middle of the summer and hit temps of 200. The ambient temp was hovering around 100. The only time the temps got higher was when I had to stop for fuel and had to backup for a piece... it got up to 215. Once I got back to the interstate. It was back down to 180. This was all out of overdrive at 68 mph.



The main thing is keep the temps below 250... . OD or out of OD.



The highest temps I have achieved is 260 trying to park my camper at the house. Some days you can stab it on the first or second time some days you cant.

 

[amsoilman]

Keep in mind that when your transmission fluid goes over 175 F. the fluid will oxidize very rapidly. This is according to a study from GM a few years ago.



175 F. trans expected to go for 100,000 miles.

For every 20 degrees F. over that, the life expectency is cut in half!

Varnish starts to form at 212 F.

Seals harden at 235 F.

Plates slip at 255 F.

Oil forms carbon at 295 F.

And any thing above 300 F. causes severe component distortion.

This is why most oil experts recommend synthetic ATF.



All info was taken from study made by GM



Wayne

amsoilman