transmission temperature

[bouterse]

We picked up a new 2016 GMC Sierra 5.3 a few weeks ago. On our first trip pulling our '19' this week, I noticed the transmission temp climbed to 93C (200F) while towing on a not too hot (24 C) day. The manual says the tranny temp should be 82 - 93 C. It seems strange that I would reach the max temp with a 3000 lb load on level terrain on a not too hot day. My previous 2011 GMC usually ran 85 - 87C while towing. Anyone else have this same problem?

Jack

[PGDriver]

Our previous 2011 Sierra 5.3 with the trailer tow package reached 235 degrees F while pulling our 5.0TA up the Salmo Creston which is a pretty good pull. It only remained there for a few minutes. I checked with my buddy who works for GM and he said that was ok for a short period of time as its around that temperature that the transmission start to break down. If it stays around 200F I wouldn't worry about it but I would change out the transmission fluid early and also keep an eye on it to make sure it doesn't smell burnt.
Cheers
Doug

[escape artist]

Originally Posted by bouterse

We picked up a new 2016 GMC Sierra 5.3 a few weeks ago. On our first trip pulling our '19' this week, I noticed the transmission temp climbed to 93C (200F) while towing on a not too hot (24 C) day. The manual says the tranny temp should be 82 - 93 C. It seems strange that I would reach the max temp with a 3000 lb load on level terrain on a not too hot day. My previous 2011 GMC usually ran 85 - 87C while towing. Anyone else have this same problem?

Jack

Hi: bouterse... Could be too soon to tow!!! Could be a "Need for speed" thing. Could be your GMC doesn't like being a tug!!! Could be that ignorance is bliss. Just guessing. Alf
escape artist N.S. of Lake Erie

[Brian B-P]

Originally Posted by bouterse

On our first trip pulling our '19' this week, I noticed the transmission temp climbed to 93C (200F) while towing on a not too hot (24 C) day. The manual says the tranny temp should be 82 - 93 C. It seems strange that I would reach the max temp with a 3000 lb load on level terrain on a not too hot day.

I don't know that there's a problem; it is within the expected temperature range.

The transmission fluid cooler is usually in the cool-side end tank of the engine coolant's radiator. Since the engine coolant temperature is regulated by the engine's thermostat, the temperature on the cool side of the radiator is pretty stable. That means that once the vehicle is warmed up, the transmission fluid is running through a consistently (very) warm bath. If more cooling is needed there will be more radiator flow, and the transmission will get more cooling as well.

This, of course, is an excuse to go on another trip and find some mountains.

Originally Posted by bouterse

My previous 2011 GMC usually ran 85 - 87C while towing.

It's entirely possible that with each new generation, GM tunes the system to run all of the fluids closer to the optimal point. Transmission fluid is supposed to be reasonably hot; although too hot destroys the fluid, too cool doesn't work as efficiently.

[Loren & Cathy]

The manual for my 2014 GMC says not to tow during the break in period of 500 miles. The hottest I have seen my transmission get was 205 F for several minutes. This was starting from a stop on a steep grade towing our 21. It normally runs around 190 not towing or towing on the level. I have the 3.73 rear end with the max tow package. Loren

[padlin]

Originally Posted by PGDriver

Our previous 2011 Sierra 5.3 with the trailer tow package reached 235 degrees F while pulling our 5.0TA up the Salmo Creston which is a pretty good pull. It only remained there for a few minutes. I checked with my buddy who works for GM and he said that was ok for a short period of time as its around that temperature that the transmission start to break down. If it stays around 200F I wouldn't worry about it but I would change out the transmission fluid early and also keep an eye on it to make sure it doesn't smell burnt.
Cheers
Doug

Pretty much identical to the GMC I had. Never became a problem but it was something I worried about. Eventually added a 2nd tranny cooler then sold the truck.

[C&G in FL]

My F150 usually runs 201-203 F towing on flats or maybe up to 208 on moderate climbs. Extended climbs I have seen 228 F. The transmissiin specialist at my Ford dealership says 240-250 is the get concerned point. Interestingly, Ford does not recommend changing the transmissiin fluid.......ever. But I think I will do it every 30,000 miles or so anyway.

[Rossue]

With our 2013 Yukon I had the trans fluid completely flushed pushing the fluid forward at 30K- along with new filter, which used about 18 quarts. Did this at a local shop(Trans King) that specializes in this technique as most flush in reverse. The dealer only drains the fluid and doesn't change the filter leaving almost half of the old fluid in which I thought was odd. We normally see 173 to 190 F on flats, however we've had to stop and let the trans cool while engine idling twice. Both were 8% grades for 8-12 miles- the last one going up to Onion Valley above Independence, CA which we stopped 3-4 times after noticing at my first check about 1/2 way up a 244 reading. It was 99 F at the start of the climb. Did a search while cooling down, and it seems that the DIC will give you an idiot light at a certain point which we didn't see. Love having the gauge. Put about 25K on last year and will probably flush again fairly soon.

[Brian B-P]

Originally Posted by C&G in FL

Interestingly, Ford does not recommend changing the transmissiin fluid.......ever.

It's pretty common to do that now. My Toyota Sienna calls for infrequent fluid changes in the severe-duty maintenance schedule... and all residents of Canada are advised to follow the severe-duty schedule. A transmission doesn't ingest outside air or contain combustion so there is no ongoing source of dirt, making fluid changes less useful. With synthetic fluids, routine changes are not generally required.

Another common trend is to omit the transmission dipstick; that was done because any benefit of having the fluid level checked was more than offset by contamination of the fluid by incompetent checkers, and by nuisance problem reports due to people checking the level incorrectly and getting alarmed when they didn't see the right level.

[Catchlight]

Bouterse, is your Sierra is using synthetic transmission fluid? If not, and your fluid temperatures continue to cause you concern, switching to synthetic might solve the problem. There are several informative posts about synthetic transmission fluids in the thread that I started before I switched over: http://www.escapeforum.org/forums/f1...luid-3592.html

[Vermilye]

Towing my 17B at 3100 lbs with a 2010 RAV4 Sport (V6 & tow package), the transmission temperature generally runs a bit over 200°F in hilly roads & summer temperatures. The highest it has ever reached was pulling to the top of Cedar Breaks National Monument - 266F° (beautiful, but I recommend you drop the trailer before the climb). The transmission overheat lamp never came on.

Synthetic fluid, official change at 100,000 miles but I changed it every 30,000 miles. I had the color checked by Toyota at every oil change & they never said it needed changing. No problems at 134,000 miles when I switched to a Tacoma. I'm getting my Scangauge II firmware updated so I can track the Tacoma's transmission temperature.

[Cypherian]

Originally Posted by Vermilye

Towing my 17B at 3100 lbs with a 2010 RAV4 Sport (V6 & tow package), the transmission temperature generally runs a bit over 200°F in hilly roads & summer temperatures. The highest it has ever reached was pulling to the top of Cedar Breaks National Monument - 266F° (beautiful, but I recommend you drop the trailer before the climb). The transmission overheat lamp never came on.

Synthetic fluid, official change at 100,000 miles but I changed it every 30,000 miles. I had the color checked by Toyota at every oil change & they never said it needed changing. No problems at 134,000 miles when I switched to a Tacoma. I'm getting my Scangauge II firmware updated so I can track the Tacoma's transmission temperature.

See your PM and before "SOMEBODY" comes in here spouting off about that which they do not know but Googled. Ask Toyota for their specs on the fluid they use and at what temp things start to break down etc.

Cypher

[kstock11]

Originally Posted by Vermilye

Towing my 17B at 3100 lbs with a 2010 RAV4 Sport (V6 & tow package), the transmission temperature generally runs a bit over 200°F in hilly roads & summer temperatures. The highest it has ever reached was pulling to the top of Cedar Breaks National Monument - 266F° (beautiful, but I recommend you drop the trailer before the climb). The transmission overheat lamp never came on.

Synthetic fluid, official change at 100,000 miles but I changed it every 30,000 miles. I had the color checked by Toyota at every oil change & they never said it needed changing. No problems at 134,000 miles when I switched to a Tacoma. I'm getting my Scangauge II firmware updated so I can track the Tacoma's transmission temperature.

That was a tough pull in our GMC Acadia towing our 19'. Only tougher climb was going into the Black Canyon of the Gunneson! For either one, we turned off air conditioning and kept our speed down. By the time you get to the top of these pulls, you feel as wiped as the vehicle!!!

[T&R]

Send off the old fluid to Blackstone Labs for analysis and you may have a better idea if your change intervals are within reason and if the fluid is breaking down or not.

Blackstone Labs

[steve dunham]

The normal (design ) temperature for my 2014 Ram ZF 8 speed transmission is 190 deg F and may rise to 240 to 250 Deg F when towing in hot weather . The newer transmissions run hotter than the older transmissions . I remember years ago driving at temps of 40 to 50 below zero and having the transmission stuck in first gear for the first 5 miles and then shifting sluggishly , no longer have those issues with the newer transmissions. There is a reason that most vehicles come with synthetic lubricants , they allow higher operating temps and better fuel economy. Many people are still in the 3000 mile oil change mentality.

[bouterse]

Finally got some info from GM today. The tranny temp on my Sierra should run 82 - 93 C (200 F), but the high temp message doesn't come on until 132 C (270 F). Looks like I shouldn't be too concerned when it hits 93.

Jack