Normal or safe temps.

Bryanjay08 · January 30, 2016

I have a 2008 gmc sierra 1500 w/t v6 and i was wondering about the normal or safe operating temperatures for the transmission. the truck only has 65000 miles on it. Ive seen it run anywhere from 150 to 215. 215 on a hot south carolina summer day sitting in traffic. ive heard and read conflicting information and would need some clarification. my engine temp always goes to 200 and stays there. Should I service the transmission? I do a little light towing. like a utility trailer or medium sized pop up camper.

Cosmic Charlie · January 30, 2016

http://www.gm-trucks.com/forums/topic/182525-normal-operating-temp/

intheburbs · January 30, 2016

Dexron VI fluid is good to well over 250° F. The warning message comes on at 265°. 215° is perfectly normal.

I'd start getting concerned around 230°. The only times I've been up that high were when we were fourwheeling in Moab in over 100° temperatures, and pulling a 7500-lb trailer up towards the Eisenhower Tunnel in Colorado, which is over 11,000 feet. And both times it never went above 235°. You'd have to have the truck working really hard to get that hot.

Bryanjay08 · January 31, 2016

thanks for the replies.

Gurrzt · January 31, 2016

Any temperature over 210F will start to burn the fluid.

crankman · January 31, 2016

If you never have had the transmission service done YES. I have a 2008 with 105,000 and ive had it done twice but I tow alot. I have never had mine to 215 towing or not seems high just sitting in traffic. Id get it serviced for piece of mind.

intheburbs · January 31, 2016

Any temperature over 210F will start to burn the fluid.

This is completely false. Read the specs on Dexron VI. If anything over 210° burns the fluid, then why did GM program the warning for 265°?

Gurrzt · January 31, 2016

So when you burn up your transmission you can buy a new one from them

NEFisher11 · February 1, 2016

I see 215 sitting in traffic also. Nothing to worry about at that temp.

white1500 · February 1, 2016

Have you considered an external oil cooler? It may or may not already have one that's integrated into the radiator.

intheburbs · February 1, 2016

So when you burn up your transmission you can buy a new one from them

Geez. What planet are you from? Maybe 30 years ago 210° might have been too hot. Technology makes things work better. Or are you one of those Luddite types?

Dex VI can go to 270° before it sees significant degradation. A close friend of mine is an engineer at GM. His job is validating/testing transmissions. His first project when he was hired was testing/validtaing the 6L80/6L90 for the GMT900 trucks. I expressed my concern about the transmission occasionally hitting 230°, and if I needed to upgrade my transmission cooler. He said, "It's completely unnecessary. We've done worse to those transmissions than you ever will."

I've logged over 20,000 miles of heavy towing all over the country. I've blown up three rear axles, but never a transmission. My '01 (now owned by a friend) is still going strong with the original transmission at 220k miles, and my '08 has the original transmission at 150k miles. I've beaten the snot out of both trucks and I drive them like I stole them.

Chevor · February 2, 2016

I have had the allison up to 240 over 300,000 miles ago. A good cleaning of the cooling coils made temps much cooler.

Gurrzt · February 2, 2016

Geez. What planet are you from? Maybe 30 years ago 210° might have been too hot. Technology makes things work better. Or are you one of those Luddite types?

Dex VI can go to 270° before it sees significant degradation. A close friend of mine is an engineer at GM. His job is validating/testing transmissions. His first project when he was hired was testing/validtaing the 6L80/6L90 for the GMT900 trucks. I expressed my concern about the transmission occasionally hitting 230°, and if I needed to upgrade my transmission cooler. He said, "It's completely unnecessary. We've done worse to those transmissions than you ever will."

I've logged over 20,000 miles of heavy towing all over the country. I've blown up three rear axles, but never a transmission. My '01 (now owned by a friend) is still going strong with the original transmission at 220k miles, and my '08 has the original transmission at 150k miles. I've beaten the snot out of both trucks and I drive them like I stole them.

210F is too hot period. The cooler the fluid temperature the cooler the transmission operates. My 2001 Z28 (Sara) with an external cooler operates @ 135-180F, out of lockup (A4) it MAY reach 200F, however it declines rapidly when in motion or freeway speeds (Upon lockup(43mph)). My 2013 Yukon operates @ 130-160F and never sees temperatures over 200F (no towing). Even if the synthetic fluid can handle temperatures in excess of 210F, the fluid is operating @ too high of a temperature, and I would consider looking into some sort of blockage.

As for these comments, KISS MY A$$

kstruckcountry · February 2, 2016

Let's keep things civil in here. You don't agree, that's ok. Leave it at that.

Usually the trans will operate ambient temperature plus 90 degrees or so. Towing in the summer it's very easy to get over 200.

Gurrzt · February 3, 2016

Here is a chart you may find helpful:

http://myautomatictransmission.com/temperature-chart.htm

If you feel comfortable at operating your automatic transmission at 250F and above, be my guest, I would rather operate the transmission between 130-160F optimally.