Transmission and engine temp questions

t?m · March 12, 2012

New 2500 with 4.10 rear that I'll be towing a trailer with. I see that the engine heats to 210 very quickley. Transmission temps are in the 140s with the short tows I've made so far.

Coming to a vehicle that tells me these things is new. What are my oh crap what do I do now temps to look for? I've read 90 above ambient for the transmission and then I've read up to 250 for the tranmission or so when towing up a grade. Engine temps pretty much always stay the same?

Sound about right?

r1byker · March 12, 2012

My engine temp never changes from 210. And about 90 above ambient for the transmission in light duty is what I see.

ChevyTech77 · March 12, 2012

Worst case scenario, they both should never go ever 220. Trans fluid starts turning to paste at 260 and well, if the engine coolant gets that high I'll be betting that the smoke coming from under the hood should have stopped you by then.

t?m · March 12, 2012

So pulling a long up a long grade I shouldn't see anything above 220? I didn't specify but it is a 6.0L gas engine.

The trailer load would be no more than 9800 lbs.

Shaners · March 12, 2012

_{I have never seen over 210 on my Duramax and have only seen over 200 on the Allison 1 time. Use tow/haul and hold it in gear on long climbs so that it isn't shifting/hunting around. You would be more likely to see high tranny temps in town (stop and go) under load because shifting is what creates the heat.}

ChevyTech77 · March 12, 2012

High rpms, especially with lack of torque convertor lock up, create just as much, if not more, heat in a trans the when they constantly shift. Believe it or not, when I leave my 6L80E in 6th gear pulling my snowmobiles around (approx. 2200 lbs but high wind resistance) and it starts hunting around in the hills, my trans temps don't really go above what they are running the same stretch in 5th, I just get sick of listenting to the trans constantly shift back and forth.

Tow/haul is only good to use when towing when you are towing/hauling 3/4 of the total allowed payload/towing limits.

dewfpo · March 12, 2012

I see 200F on the atf gauge all the time in the summer, especially when pulling a lot in 1st & 2nd gear. My gauge consistently reads 100F+ ambient.

DEWFPO

Doug_Scott · March 13, 2012

_{I have never seen over 210 on my Duramax and have only seen over 200 on the Allison 1 time. Use tow/haul and hold it in gear on long climbs so that it isn't shifting/hunting around. You would be more likely to see high tranny temps in town (stop and go) under load because shifting is what creates the heat.}

Heat is created by the torque convertor when it is not locked up, not by the shifting of the gears. You will see more heat in the transmission if you are running without the TC locked up, or it is not in rotary flow.

t?m · March 14, 2012

I talked to the dealer today....well some girl who answered the phone and spoke with service and called me back. I was told 230 for the tops on the transmission temp for worrying.

210 being a normally temp to be at. I thought the thermostat opened up after 195 so you should get some cooling after that? Does it only open partially so it maintains the temp vs cooling it down some?

SouthCo · March 14, 2012

I've got 3 GM vehicles (tahoe, yukon denali xl and sierra; ok just sold the tahoe) and I've never seen the engine temp above 210 on any of them. Only my new Sierra has a trans temp. Today, for instance, it was 81 degrees outside and the trans was running 131 degrees. Dont watch it much but don't recall seeing the trans on the Sierra above about 150 degrees.

dewfpo · March 14, 2012

I talked to the dealer today....well some girl who answered the phone and spoke with service and called me back. I was told 230 for the tops on the transmission temp for worrying.

210 being a normally temp to be at. I thought the thermostat opened up after 195 so you should get some cooling after that? Does it only open partially so it maintains the temp vs cooling it down some?

The thermostat on the engine starts to open at 195F and isn't fully open until something like 205 or 210F.

DEWFPO

jake111 · March 16, 2012

I'm going to agree with the 220*F/220*F limit. At those temperatures I would be changing something ASAP!! (slowing down, pulling over, reaching the top of the hill)

I don't know about other GM models, but on the 2004.5/2005 LLY Duramax the dash gauge is (what appears to be deliberately misleading) "optimistic". 160*F displayed might really be closer to 130*F; ~200*F display (just left of center) is anywhere between 185*F and 215*F, 210*F is actually about 220*F, 220*F displayed is pushing 235*F. Because of this, you might want to put a scanner that can read the real engine temp off the bus (e.g., Scangauge, Edge, etc.), at least long enough to verify the dash gauge.

Again, for the LLY models, others who have taken the measurements have found the transmission temp displayed is actually very close to actual. But at 220*F I'm still pulling over.

whitesnake01 · March 17, 2012

When I tow with my 05, the trans temp typically sits around 190-210. It can climb higher, but I do not think I've seen it above 225. The engine sits at 210 and sometimes climb up to 230, but is quickly knocked back down again with the help of the fan clutch.

Only exception to this is the infamous faulty gauge syndrome, which I am suffering from right now. Both trans temp and oil pressure is wonky. It is not unusual for me to start the truck in the morning and have the trans temp at 230 the moment it comes on.I've also had the oil pressure swing from 20PSI to 180+ PSI during a normal drive to work.

tooch420 · March 18, 2012

I've got 3 GM vehicles (tahoe, yukon denali xl and sierra; ok just sold the tahoe) and I've never seen the engine temp above 210 on any of them. Only my new Sierra has a trans temp. Today, for instance, it was 81 degrees outside and the trans was running 131 degrees. Dont watch it much but don't recall seeing the trans on the Sierra above about 150 degrees.

I agree, my tranny is always around 150. My engine temp a little lower than what is was when i had the mech fan on (dual electric setup now),,about 200