towing tranny temps

[Mattt]

Ive got an 01 2500HD, 6.0, AT, CCLB, 4WD that I tow a 28' toy box trailer with. Trailer weighs 8000 lbs(6900 axles, 1100 tongue) empty and is rated for up to 11,500. I think I normally load it to about 10,000 lbs.

 

Normal around town driving....trans temp is 150

 

Towing the trailer, flat easy ground......trans temp is 200 or right under

 

Towing trailer, up hills, or revs up(down in 3rd gear), headwind, etc........trans goes to 225-230-ish.

 

Once I get it back to flat easy ground, trans temp drops back down to 200. I dont see a tranny problem(since the temps fall once the "obstacle" is gone), other than Im working this trans for all its got. Id like to keep it from even going that high.

 

Anyone here added a second or larger than stock trans cooler?

 

Where did you plumb it in? What brand, size did you use? Any recommendations??

 

Also, Ive heard as long as you keep the trans under 240-250, you are okay. Am I really asking for trouble with 225? Fluid looks and smells fine, but I know from experience that heat is the trans worst enemy.

[Black02Silverado]

Adding a second trans cooler would help. As for brand, size and where to put it I can't say since I have not installed one. Some say in front of your radiator some say in back. I would say in front unless you live in the great white north. Then you would have to deal with the tranny never getting up to temp in the hard cold of winter. Don't forget to run a good synthetic fluid in the tranny like Mobil 1 or AMSOIL. That will help with the extra heat.

 

Found some good info at TCI automotive

[Shaners]

Those temps sound normal for the 4L80E under those conditions.

 

I can understand why you would want to keep the fluid as cool as possible though... Maybe a change to a good synthetic like was mentioned above, might not be a bad idea, along with just some regular general maintenence.

[Mattt]

Thanks for the pointers. I didnt know that running synthetic trans fluid would help keep the temp down. How much of a temp difference are we talking by switching to synthetic ATF?

[Mattt]

Bump

 

No one has added a secondary cooler?

[Supercop8100]

Whats the normal temp for the allison un-loaded?

[Black02Silverado]

Thanks for the pointers. I didnt know that running synthetic trans fluid would help keep the temp down.  How much of a temp difference are we talking by switching to synthetic ATF?

 

 

 

 

 

Some with after market tranny temp gages have noticed a 5 to 10 degree drop in temp after switching over to synthetic ATF. With my factory gage I noticed about a 5 degree drop.

[Polak]

Whats the normal temp for the allison un-loaded?

 

<{POST_SNAPBACK}>

 

 

 

 

Indy to Vegas w/ trailer 210.

 

Vegas to Indy w/o trailer was the same.

 

This was in August '04. Even in the "desert" areas of Utah, Arizona, & Nevada when the ambient reached 100+ the tranny didn't waiver.

[Black02Silverado]

Whats the normal temp for the allison un-loaded?

 

 

 

 

 

 

Indy to Vegas w/ trailer 210.

 

Vegas to Indy w/o trailer was the same.

 

This was in August '04. Even in the "desert" areas of Utah, Arizona, & Nevada when the ambient reached 100+ the tranny didn't waiver.

 

 

 

 

 

 

 

Got to love the Allison Tranny!

[Shaners]

Whats the normal temp for the allison un-loaded?

 

<{POST_SNAPBACK}>

 

 

 

 

On a warm summer day, mine will run about 150*

[whitesnake01]

I have a 4L80E in my 93 Suburban. Biggest improvement in cooling for towing was to replace the radiator. Mine was overdue. You want want to consider rodding out the radiator as a first step. I ended up getting a custom radiator for mine: 5 rows of core and 18 fins/inch (versus 4 rows of core and 12 fins/inch). Made a world of a difference.

 

If you do not drive your truck in the winter you can also let your tranny cooling loop start with your radiator and then go through a front mounted element as opposed to the other way around. The latter would be a bad idea for cold weather driving, but since I do not do any cold weather driving, it is fine. The tranny needs a certain amount of heat to work well. Too low and it poses other problems.

 

I use AMSoil full synthetic in my tranny. I've bottomed out the meter on it a few times, and it stops at 265F.. I've had no problems with it and no shavings in the filter. Those sorts of temps are from steep, extended climbs, in hot weather.

[Bart2500HD]

Those temps don't look too hot for your tranny. My advice is to change the tranny fluid every year if you continue to tow regularly.

[Mattt]

Thanks again everyone for all the info.

 

At what temp should I really start to get CONCERNED?

[Mattt]

I have a 4L80E in my 93 Suburban. Biggest improvement in cooling for towing was to replace the radiator. Mine was overdue. You want want to consider rodding out the radiator as a first step. I ended up getting a custom radiator for mine: 5 rows of core and 18 fins/inch (versus 4 rows of core and 12 fins/inch). Made a world of a difference.

 

If you do not drive your truck in the winter you can also let your tranny cooling loop start with your radiator and then go through a front mounted element as opposed to the other way around. The latter would be a bad idea for cold weather driving, but since I do not do any cold weather driving, it is fine. The tranny needs a certain amount of heat to work well. Too low and it poses other problems.

 

I use AMSoil full synthetic in my tranny. I've bottomed out the meter on it a few times, and it stops at 265F.. I've had no problems with it and no shavings in the filter. Those sorts of temps are from steep, extended climbs, in hot weather.

 

<{POST_SNAPBACK}>

 

 

 

I think the newer gen truck has an external trans cooler, no? I know there is at least one small cooler in front of the radiator. Im not having a problem with overall heat, engine runs rock solid 200 or just under. Im just trying to dissipate some of the heat that my heavy tow load is making.

[Mattt]

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