Trans Temp

jerdog · 07-12-2016, 04:27 PM

Going to be towing accross the Nevada desert in two weeks in the heat of the day. My 2013 GMC Sierra has a transmission temp gauge on the read outs. At what temp should I start getting concerned?

Thanks for any advice on this. I know a trans cooler is a great idea but just don't have time or $ right now to put one on.

Firefighter78 · 07-12-2016, 05:38 PM

Automatic transmissions do not last long being run consistently over 195F. No matter the oil that's put in or when it's changed. Aftermarket trans coolers are not expensive, easy to install. They not only give significantly more cooling capacity, they also increase fluid capacity which is good. Personally if your concerned about it and your towing above 7000 lbs, then would go for the purchase. Also if you haven't changed the trans fluid and filter in the last 30k miles, would do that at the same time. Don't let anyone talk you out of the trans cooler or talk you into a trans flush. Good luck

Grumpy · 07-12-2016, 06:19 PM

Do you have a DURAMAX with an ALLISON? If so here is info from DIESEL PLACE:

The transmission is restricted to 330F (converter out); but, it will take 350F for a long time. It can run all day long at 250F but most folks run around 180F-220F typically.

Seann45 · 07-13-2016, 07:14 AM

When the needle starts to approach the red zone pull over and let it idle for 20 min. After the trip pull the dipstick and if the fluid is not red or smells burnt replace it immediately. Is it possible to make the trip at night?

Flapper · 07-13-2016, 07:27 AM

Hmmm, beginning to sound like what I heard when I asked the question. Anywhere from 195 to 350, which is quite a range! In my case, I only have a digital readout. There is no needle, which the OP may or may not have. Even the dealer had no idea what was an acceptable range. So all I know is that hotter over time is not good! Will be interested to see if this thread can give a bit more solid information.....

SmokerBill · 07-13-2016, 07:27 AM

I know that GMC and RAM pickups are different animals, but I've found that if I manually shift down to 4th gear and set the transmission to tow-haul mode, my transmission runs relatively cool. In a higher gear, the torque converter disengages and engages on minor elevation changes, and with my truck, that's what seems to cause the transmission to run at a higher temp. 4th gear in tow-haul mode in my RAM puts the gearing in a 1-1 ratio. Fuel mileage suffers a bit from the higher RPMs (around 2200@60mph), but I believe it's easier on the drive train to run it that way.

Bassdogs · 07-13-2016, 08:03 AM

Was told by GM service tech that 230 - 250 range on a V8 with auto trans was not a problem and of no concern. My 08 pulling about 9000 lbs during hot weather would rise to around 230 which is why I ask the tech. With out tow the temp in the same circumstance was around 195. When towing temp [in tow mode] reached 230 I would make a rest stop for 30 minutes and would let the engine run for about 10 minutes at idle before turning it off.

I had zero problems with my 08 gasser but upgraded to a duramax which was in my plan when we upgraded to the heaver TT. We are retired and make several longer tows per year and wanted the extra tow capacities that the 3/4 ton offered.

Grumpy · 07-13-2016, 08:09 AM

Quote:

Originally Posted by Flapper

Will be interested to see if this thread can give a bit more solid information.....

The ALLISON info on DIESEL PLACE is from a retired ALLISON engineer.

Wireman · 07-13-2016, 08:10 AM

jerdog, does your GMC have a factory tow package? Are you towing within the trucks capacity? How many miles on the truck?

Change your tranny fluid and like firefighter78 said, don't do a tranny flush. Replace the fluid and change the filter if it's replaceable.

Go with at least a semi synthetic fluid or full synthetic though it's more costly.

The Allison's are bullet proof if that's what you have. I had 1 in my class A I owned for 13 years. Changed the fluid & filter every 15000 miles. Never an issue with it.

I had a scan gauge I monitored the tranny temp with and if I can remember right the temp never exceeded 225 degrees in the mountains and the heat, and that's a #22,000 MH towing a car.

jerdog · 07-13-2016, 08:35 AM

Thanks for all the advice, everyone. The truck is a '13 GMC Sierra (Gas Engine) with the factory tow package. I was just wanting to establish a baseline as to what temperature I should be concerned with. ie: how hot is too hot.

**norty1** · 07-13-2016, 08:40 AM

Do you have a temp guage or just an indicator light?

jerdog · 07-13-2016, 08:43 AM

Quote:

Originally Posted by norty1

Do you have a temp guage or just an indicator light?

Just a digital readout.

**norty1** · 07-13-2016, 08:48 AM

I don't see why you are interested in the temps if you can't determine what is is anyhow.

If you see a spike that stays spiked, I would advise pulling over and letting it idle a while.

My old rig had just a indicator and I went thru 2 transmissions before getting a gauge that told me the actual temps. Hot transmission fluid is hard on seals.

DocBrown · 07-13-2016, 08:53 AM

Older GMs, pre 2006 that is, that used the 4L60E transmission were very sensitive to high temps, 200+ for long periods. In 2006 GM introduced Dex VI fluid, which is a synthetic blend that keeps your trans cooler than Dex III did. GM recommends DEX VI for all pre 2006 GMT trucks now. Your truck has a 6 speed and is much more modern than the 4L40E 4 speed that I have.

I had an incident last year where my temps in my Sierra were running up to 220. This was around Indy, outside temps were 90 and high humidity. Not for long periods, but for an hour or so. Long enough to concern me. I stopped at a shop in Gatlinberg and talked to one of the guys there and he looked at my fluid and said everything looked fine, and those temps were no big deal, enjoy the rest of my trip, which I did.

BTW, as an FYI, my high temps were caused by my custom grill insert not allowing enough air flow. When I realized that I took the insert off and the temps dropped to 170-180 on the flats, 190-200 in Tennessee's mountain passes for short bursts. Point being, with your small trailer you do not need a auxiliary transmission.

I think I would start to get concerned at 230+ for long periods. Short burst should not be a problem, especially with a trailer the size you have.

Quote:

Originally Posted by norty1

I don't see why you are interested in the temps if you can't determine what is is anyhow.

He can. The digital gauge he's talking about gives an actual temperature number.

**norty1** · 07-13-2016, 08:59 AM

Good, Sorry, I didn't know. My gauge indicated a "normal" temp for me when towing flat and at highway speeds. After a while you get a feel when it is not normal anymore. After I had the gauge installed, I would pull over when it was approaching 210 deg.

Usually that was in 4-6% grades. Never had anymore seal problems after that.

**Crabman** · 07-13-2016, 09:30 AM

Quote:

Originally Posted by DocBrown

Older GMs, pre 2006 that is, that used the 4L60E transmission were very sensitive to high temps, 200+ for long periods. In 2006 GM introduced Dex VI fluid, which is a synthetic blend that keeps your trans cooler than Dex III did. GM recommends DEX VI for all pre 2006 GMT trucks now. Your truck has a 6 speed and is much more modern than the 4L40E 4 speed that I have.

I had an incident last year where my temps in my Sierra were running up to 220. This was around Indy, outside temps were 90 and high humidity. Not for long periods, but for an hour or so. Long enough to concern me. I stopped at a shop in Gatlinberg and talked to one of the guys there and he looked at my fluid and said everything looked fine, and those temps were no big deal, enjoy the rest of my trip, which I did.

BTW, as an FYI, my high temps were caused by my custom grill insert not allowing enough air flow. When I realized that I took the insert off and the temps dropped to 170-180 on the flats, 190-200 in Tennessee's mountain passes for short bursts. Point being, with your small trailer you do not need a auxiliary transmission.

I think I would start to get concerned at 230+ for long periods. Short burst should not be a problem, especially with a trailer the size you have.

He can. The digital gauge he's talking about gives an actual temperature number.

I replaced the fluid in my tranny with the Dexron VI a few years back. It will tolerate more heat then the old Dex3. Mine has the analog gauge and I have approached 200 a few times when its real hot out. But that should be a non issue with the synthetic Dex6.

Grumpy · 07-13-2016, 09:34 AM

Quote:

Originally Posted by Crabman

I replaced the fluid in my tranny with the Dexron VI a few years back. It will tolerate more heat then the old Dex3. Mine has the analog gauge and I have approached 200 a few times when its real hot out. But that should be a non issue with the synthetic Dex6.

But if they have an ALLISON 06 and up or around there it will be using TRAN-SYD which will tolerate very high temps. You can actually use that in any GM trany from what I understand. Not cheap, but the best you can get.

SouthCo · 07-13-2016, 09:48 AM

OP with a factory tow package I believe u should have a transmission cooler standard. My previous truck was a 2010 GMC 1500 with tow package and it included a trans cooler.

Camper_bob · 07-13-2016, 10:02 AM

Quote:

Originally Posted by SouthCo

OP with a factory tow package I believe u should have a transmission cooler standard. My previous truck was a 2010 GMC 1500 with tow package and it included a trans cooler.

My '12 Sierra also had the HD tow package and thus an auxiliary trans cooler. OP may already have one?

I got that trans up to around 220 or 230 a couple times and wasn't very comfortable with it, but as I've read here and other places, for short times, it shouldn't be a concern. That trans would run between 180-190 during standard towing. I got to where I would watch it pretty close when conditions warranted (traffic, steep grade, etc).

jerdog · 07-13-2016, 10:39 AM

Quote:

Originally Posted by Camper_bob

My '12 Sierra also had the HD tow package and thus an auxiliary trans cooler. OP may already have one?

I got that trans up to around 220 or 230 a couple times and wasn't very comfortable with it, but as I've read here and other places, for short times, it shouldn't be a concern. That trans would run between 180-190 during standard towing. I got to where I would watch it pretty close when conditions warranted (traffic, steep grade, etc).

Thanks for all the info folks! It does have the small factory trans cooler mounted in front of the radiator. I think I'll be fine. My question was answered I guess. Looks like prolonged periods above 220-230 might be a concern so I'll keep an eye on it.

You may also like: