Towing in HOT temps

[RDEVans]

Hey all,

I have a 2010 Sierra 1500 AT Z71 with the 6.2. It has the max trailering package, 3.73 gear ratio. Believe it has the heavy duty oil and trans coolers. Towing a 5000-5500 travel trailer in 105-110 heat. Before I left I had all the fluids changed. First part of the trip it was cloudy, 70s/80s into low 90s and engine temp stayed locked at 210 and trans temp was running equal to air temp plus 90-100 (example air temp 85 trans temp 175-185). Second part of trip was very rolling. Air temps got up to 105-110 for about 6 hours while towing. Driving in 5th at 60-62 mph about 2000 rpms Engine temp would rise to 212-215 for the first 3-4 hours of the trip and trans ran 200-210. On bigger hills would climb to 215 then come back down after the crest. Towards the end of the trip after what I assumed was heat saturation the engine temp would hit 220 on a climb and transmission temp hit 216-217. The last little bit of the trip there was a very steep climb engine temp hit 220 and trans hit 230 right before the peak. Over the peak and on the way down trans was cooling back down. I kept it at 35-50 thru windy mountain roads last part of the trip which was another climb. Staying at those speeds the engine temp dropped to 210 but trans climbed into the 220s.

I was ok with the engine temp and expected that. Any concerns with the trans temp or was it ok because everything was just heat saturated and it would drop slowly on downhills? I tried to keep from shifting and bunting gears but should I have just gone to 4th and run at 2600-3000 rpm’s almost the whole time?

Thanks all.

 

[strutaeng]

Those temperatures are fine, especially since you say the peak temperatures go back down after cresting the hills/mountains.

You can always install a larger aftermarket transmission external cooler. Maybe consider lowering slightly the electric fans cut-in temperatures on the tune.

 

[OR VietVet]

Yes, install a larger transmission cooler and make double sure all of the cores are cleaned out for good air flow. Heat can and will radiate forward.

Is there a tow/haul mode on the transmission?

 

[PG01]

Hey all,

I have a 2010 Sierra 1500 AT Z71 with the 6.2. It has the max trailering package, 3.73 gear ratio. Believe it has the heavy duty oil and trans coolers. Towing a 5000-5500 travel trailer in 105-110 heat. Before I left I had all the fluids changed. First part of the trip it was cloudy, 70s/80s into low 90s and engine temp stayed locked at 210 and trans temp was running equal to air temp plus 90-100 (example air temp 85 trans temp 175-185). Second part of trip was very rolling. Air temps got up to 105-110 for about 6 hours while towing. Driving in 5th at 60-62 mph about 2000 rpms Engine temp would rise to 212-215 for the first 3-4 hours of the trip and trans ran 200-210. On bigger hills would climb to 215 then come back down after the crest. Towards the end of the trip after what I assumed was heat saturation the engine temp would hit 220 on a climb and transmission temp hit 216-217. The last little bit of the trip there was a very steep climb engine temp hit 220 and trans hit 230 right before the peak. Over the peak and on the way down trans was cooling back down. I kept it at 35-50 thru windy mountain roads last part of the trip which was another climb. Staying at those speeds the engine temp dropped to 210 but trans climbed into the 220s.

I was ok with the engine temp and expected that. Any concerns with the trans temp or was it ok because everything was just heat saturated and it would drop slowly on downhills? I tried to keep from shifting and bunting gears but should I have just gone to 4th and run at 2600-3000 rpm’s almost the whole time?

Thanks all.

I always liked these graphs…sorta sticks in the head

when you are done with your trip i would automatically change both fluids… engine oil and trans fluid. Or….if you are staying in one place for a while you can always have it done prior to returning home, then again when you get home, If you are worried. i believe finishing the trip and changing when home is fine. Id rather have fresh fluids than swapping a transmission.

 

[RDEVans]

Those temperatures are fine, especially since you say the peak temperatures go back down after cresting the hills/mountains.

You can always install a larger aftermarket transmission external cooler. Maybe consider lowering slightly the electric fans cut-in temperatures on the tune.

Thank you. Any recommendation on an aftermarket external trans cooler? Do most shops do tune work or is that someplace I just have to look up specific? I’ve never had anything done like that. Also considering moving up to a 3/4 ton truck. Would you suggest still doing the external cooler and tune? Thanks!

Yes, install a larger transmission cooler and make double sure all of the cores are cleaned out for good air flow. Heat can and will radiate forward.

Is there a tow/haul mode on the transmission?

Yes, I was in tow/haul mode. Suggestion for a cooler? Thanks!

 

[RDEVans]

I always liked these graphs…sorta sticks in the head View attachment 490188when you are done with your trip i would automatically change both fluids… engine oil and trans fluid. Or….if you are staying in one place for a while you can always have it done prior to returning home, then again when you get home, If you are worried. i believe finishing the trip and changing when home is fine. Id rather have fresh fluids than swapping a transmission.

Thanks for the charts. It should be cooler and generally downhill on the way home. Yes, will change fluids. Can you add an aftermarket oil temp pressure gauge? And I have heard that maybe GMc/ Chevy engine temp gauges are not the most accurate. Can you add a more accurate aftermarket temp gauge? Thanks!