Max Chevy Trans Temperature

[spock123]

Originally Posted by Davidjeff

Spock,

Not being versed in gm trans as I am a Ford tech dealing with only Powertrains for the last 20 years, your description coupled with your mileage would have me looking at possible excessive clearance or sticking solenoids (shift) for the respective clutch in the downshift you feel the jerk in. If the jerk downshift can be described as harsh and you can feel it running solo (no trailer/load) this would be my first thought. As one has stated it is possible for a u-joint but normaly this will be coupled with driveline vibration either under load or on coast. If you have a carrier brg on a 2 piece driveshaft I would also look closely at the rubber mounting to retainer strap for slack. Not knowing more information and being unable to feel the problem I would suggest duplicating the problem while taking a mechanic on a test drive possibly with the trailer in tow if it is more severe. On the Fords running aftermarket programmers we see excessive Direct clutch wear creating issues on downshift mainly in the torque shifts both 5-6 speed styles. This is normally caused by the programming and the constant shifting they create. I'm not against programmers by any means but it is good knowledge to know.

Thanks. I'm between a rock and a hard place, I have to take camper to the factory from NC for cap replacement. I have been waiting on this for six months.


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[jestoy7]

Anyone on here that tows with a half ton GM watch their coolant temps? Can't get a straight answer on a lot of the threads I've read. My 6.2L runs at 210 99% of the time, but when pulling in the heat, coolant temps creep up a little and I'm wondering when I should worry. I flushed my coolant, new hoses and thermostat. Added a secondary tranny cooler and it does a great job keeping tranny good.

[18CrewDually]

Originally Posted by jestoy7

Anyone on here that tows with a half ton GM watch their coolant temps? Can't get a straight answer on a lot of the threads I've read. My 6.2L runs at 210 99% of the time, but when pulling in the heat, coolant temps creep up a little and I'm wondering when I should worry. I flushed my coolant, new hoses and thermostat. Added a secondary tranny cooler and it does a great job keeping tranny good.

What is "creep up a little"? 220°f towing up a hill is no worry. 240 is worry territory and it's time to pull over.

[jestoy7]

It got to 220 this Monday driving on the highway at about 67-69mph (2k rpms in tow mode). 83 degrees ambient temperature, tranny was at 190 degrees. Relatively flat Florida highway.

Last year I had much higher temps (up to 3/4 line on the gauge) towing in higher heat. So I did the thermostat, new hoses, flushed coolant and put in water wetter.

I'd hate to have to worry this year as we plan a lot of trips this summer.

[18CrewDually]

Originally Posted by jestoy7

It got to 220 this Monday driving on the highway at about 67-69mph (2k rpms in tow mode). 83 degrees ambient temperature, tranny was at 190 degrees. Relatively flat Florida highway.

Last year I had much higher temps (up to 3/4 line on the gauge) towing in higher heat. So I did the thermostat, new hoses, flushed coolant and put in water wetter.

I'd hate to have to worry this year as we plan a lot of trips this summer.

I don't know what your towing with other than a 1500 GM and don't know the weight or trailer you're towing but just slowing down to 60-62 will help with temps. You may just be expecting to much out of a 1500 running it too hard. Do what you can to keep it from hitting 240.

[jestoy7]

My bad, I have a 233S (just got it and haven't scaled it). Dry it's 4747, I'm guessing from scaling my old camper that I have about 400 lbs in gear. The Escalade I have is the ESV (6.2L with the 6 speed) and it is AWD with 3.42 gears. Towing capacity is 7200.

The episode of higher coolant temp last summer was with my Jayco that weighed 3900 with all of our gear in it.

If I go down to 62, it'll drop gear and still be at that RPM.

I read somewhere that 230 degrees is where GM would kick on the high fan speed, but couldn't confirm that. Maybe getting a tune and see admit changing that setting to a lower value?

[18CrewDually]

Originally Posted by jestoy7

My bad, I have a 233S (just got it and haven't scaled it). Dry it's 4747, I'm guessing from scaling my old camper that I have about 400 lbs in gear. The Escalade I have is the ESV (6.2L with the 6 speed) and it is AWD with 3.42 gears. Towing capacity is 7200.

The episode of higher coolant temp last summer was with my Jayco that weighed 3900 with all of our gear in it.

If I go down to 62, it'll drop gear and still be at that RPM.

I read somewhere that 230 degrees is where GM would kick on the high fan speed, but couldn't confirm that. Maybe getting a tune and see admit changing that setting to a lower value?

You didn't say what year but I have an 11 Denali 6.2 AWD with manual shift. If yours has that try shifting down 1 gear to see if there's a difference. I don't think I'd worry unless I was seeing 240 on a regular basis.
The condition of the aluminum radiator inside can cause issues if corrosion clogs the tubes. Coolant should be changed 5 yrs or sooner and if not corrosion will set in. Again I don't know how old your Caddy is.

[jestoy7]

Yeah same gen as yours. Mine is 2008 with 107k on it. I bought it last year to tow our camper with 95k on it and have done a lot of work to it.

During that same trip that the truck went up to 3/4 coolant, I managed to get it back down to 2/3rds down. As soon as we got off the highway and to the traffic light, the truck stalled and wouldn't start. An hour later (while waiting for AAA), it finally fired up with no engine codes at all. Did some research on possibilities and addressed them all: New fuel pump, new crank position sensor, second tranny cooler, and the coolant stuff. So I'm a little paranoid with this bigger camper... Maybe I should consider swapping the radiator, the only other replacement after that would be a new waterpump.

[18CrewDually]

You may want to pick up a ScangaugeII to monitor coolant and oil Temps in real numbers. Cluster gauges are not that accurate.
Or if you get an ELM327 OBDII Bluetooth adapter from Amazon and download Torque Pro on your smart phone or tablet you can monitor parameters and check for codes.
(On edit) You should be able to scroll through the info center to view these Temps in digital format.

Also if it gets hot, pull over and feel the upper hose. It should be hot too indicating flow. Be sure to check the radiators fins too. Bugs and dirt can restrict airflow enough to hurt it's effeciency.

[jestoy7]

Yeah, I did the OBDII tool recently. So the numbers from Monday (my first post) are exact values from the ECU. Which is why I'm now asking about coolant temps. The Escalade has the exact tranny value in the cluster, but the scan tool now gives me true coolant temp.

[lbrjet]

Something doesn't sound right as towing those weights shouldn't be pushing that engine very hard. On my Ford, the fan kicks in to high gear midway between 210 and 220 which has only happened twice in 25K towing miles. The highest I have ever seen is 217 and that was towing Phoenix to Flagstaff in July. (1100 ft to 7000 ft elevation). And I am towing 9K with a 5.4L engine.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[18CrewDually]

Originally Posted by lbrjet

Something doesn't sound right as towing those weights shouldn't be pushing that engine very hard. On my Ford, the fan kicks in to high gear midway between 210 and 220 which has only happened twice in 25K towing miles. The highest I have ever seen is 217 and that was towing Phoenix to Flagstaff in July. (1100 ft to 7000 ft elevation). And I am towing 9K with a 5.4L engine.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

3.42 gears and All Wheel Drive makes it work harder.

[elchilero53]

Originally Posted by jestoy7

Anyone on here that tows with a half ton GM watch their coolant temps? Can't get a straight answer on a lot of the threads I've read. My 6.2L runs at 210 99% of the time, but when pulling in the heat, coolant temps creep up a little and I'm wondering when I should worry. I flushed my coolant, new hoses and thermostat. Added a secondary tranny cooler and it does a great job keeping tranny good.

My Tahoe with the 5.3L, 6-speed and 3.42 rear-end runs at about 210 on the coolant with a tranny temp of about 185 to 195 degrees in summer temps. Climbing long hills, the temps start rising up to about 205 on the tranny and climbing to 220 on the radiator. When the temp gauge starts climbing, I kill the A/C and the temp returns to normal. Letting the air blow across the cooling coils without the compressor running still keeps the cab cool. I'll roll the windows down if it gets stuffy. Keeping the extra heat from the A/C out of the mix helps tremendously in keeping temps down and the tranny cool. Also, keeping it under 65 and not pushing hills too hard helps a whole lot, too.

[GreenImp]

Originally Posted by jestoy7

If I go down to 62, it'll drop gear and still be at that RPM

This is true...more or less, but with the lower gear ratio the drivetrain will not be working as hard (RPM's are not the only piece of the puzzle).

[dannyabear]

The 6.2 is an all aluminum 'hot rod' engine, not a towing engine, that is why it is not offered in 2500/3500 trucks, GMs towing engine is still the 6.0

[northstar1960]

Originally Posted by jestoy7

Anyone on here that tows with a half ton GM watch their coolant temps? Can't get a straight answer on a lot of the threads I've read. My 6.2L runs at 210 99% of the time, but when pulling in the heat, coolant temps creep up a little and I'm wondering when I should worry. I flushed my coolant, new hoses and thermostat. Added a secondary tranny cooler and it does a great job keeping tranny good.

Have you thought about installing a cooler T-stat ? maybe a 180 . my 3/4 6.0 runs about 190 99% of the time when towing and hit maybe 200 pulling steep grades Tranny temps avg 165 maybe 190 when pulling steep grades . when not towing runs 180 and 145 tranny .

[Sailor Bill]

I had the same question a few years ago so I went to a neighbor of mine that was a Trans rebuilder for a national reman. of of drive trains. His answer was/is as long as the temp of the trans fluid does not exceed the operating temp of the engine you are OK and that all late model trucks have sensor alarms that will warn you before you get to that temp.

[18CrewDually]

Originally Posted by Sailor Bill

I had the same question a few years ago so I went to a neighbor of mine that was a Trans rebuilder for a national reman. of of drive trains. His answer was/is as long as the temp of the trans fluid does not exceed the operating temp of the engine you are OK and that all late model trucks have sensor alarms that will warn you before you get to that temp.

Yes but in most cases once it sets the warning light it's already too late.
That's why your neighbor has a job.

[jestoy7]

Thanks everyone for the input! I'll look into the lower temp thermostat or even drilling a pin hole into my new one. I'm also considering pulling out my radiator and checking it out. The temps in Florida are no joke and we don't want to be hindered by it.

[jestoy7]

Originally Posted by elchilero53

My Tahoe with the 5.3L, 6-speed and 3.42 rear-end runs at about 210 on the coolant with a tranny temp of about 185 to 195 degrees in summer temps. Climbing long hills, the temps start rising up to about 205 on the tranny and climbing to 220 on the radiator. When the temp gauge starts climbing, I kill the A/C and the temp returns to normal. Letting the air blow across the cooling coils without the compressor running still keeps the cab cool. I'll roll the windows down if it gets stuffy. Keeping the extra heat from the A/C out of the mix helps tremendously in keeping temps down and the tranny cool. Also, keeping it under 65 and not pushing hills too hard helps a whole lot, too.

Hey man, what year is your Tahoe?