Allison Transmission temp while towing

Outdoorsman · November 14, 2012

I watched my Allison transmission temperatures the other day while towing my travel trailer. Temps climbed up to the low 190s. Is this what I should expect or should it be lower? I've only had the truck a couple of months and I doubt the trans fluid has been changed. I have 72k miles on my '08.

8.1HD/ALLISON · November 15, 2012

There are alot of variables to that. Outside temp plays a big difference too. I am assuming travel trailer is pretty heavy? I would say that 190 would be in the normal range.

Outdoorsman · November 16, 2012

It was in the mid-70s and my TT weighs in at about 7400 lbs. I was kinda concerned about how high it went but thanks for the reply. I'll feel better next time.

Z45 · November 16, 2012

Thats normal operating temp, read your owners manual as it says 180°-200°.

Outdoorsman · November 16, 2012

I bought my truck used and without an owners manual. I wish I had one! Thanks Mike for the details though! I feel better.

00Silverado4x4 · November 19, 2012

PM RyanbabZ71, he has a link to a website to owners manual. I had it but can't find it off hand.

00Silverado4x4 · November 19, 2012

PM RyanbabZ71, he has a link to a website to owners manual. I had it but can't find it off hand.

Found it, this should get you a digital copy of your owners manual...

https://www.extendedgmwarranty.com/owners-manual/chevrolet_owner_manuals.html

Hope it helps.

Z45 · November 19, 2012

2008 Sierra Owners Manual

Getting to Know your 2008 GMC Sierra

GMC Owners Center

Outdoorsman · November 19, 2012

Great, thanks guys!

Wintersun · August 14, 2013

The transmission fluid temp should be roughly 60 degrees above the ambient air temperature. My fluid temp is a lot hotter when driving through areas where it is 100 degrees on a summer day than through the same area in the wintertime with much lower outside air temps.

Unless the fluid level is low you will not be able to get it hot enough to cause a problem. If I saw temps over 220 degrees I would want to check out the transmission to see what might be wrong.

There are aftermarket transmission pans to increase the amount of fluid and this can provide more of a heat reservoir for going up a long grade with a heavy tow in hot weather. Going up a grade one is usually driving at slower speeds so there is less airflow over the cooling fins at a time when the transmission is still working hard and generating heat.

The Tow Haul mode is designed primarily to minimize torque converter slippage and keep the transmission running cooler overall with heavy loads. It may make for harder shifts but it is protecting the transmission.

I have been very impressed with my LML and Allison transmission combo. Driving with a 4,000 lb. load in the bed at high elevations (thin air) going up long 7% grades in 113 degree whether the highest the transmission temp registered was 178 degrees.