Tacey10

I have a 2009 Express 1500 v6 Auto trans. I just bought it used. 85,000 miles, runs great. But, when I tow my trailer with it, i get a "hot transmission idle engine" message when I run it on the freeway. I had the tranny fluid and filter changed, and a tranny oil cooler installed. It still gets hot only on the highway. The trailer is a single axle 14ft cargo trailer which weighs around 3,000 pounds loaded. The van is rated to be able to handle 5900 pounds towing. Anyone else have this problem? Thanks.

RacerX

Are you towing in OverDrive or Drive? You should be towing in Drive(3rd gear) all the time.
ANd check the cooler to make sure its in the right place to receive enoug air flow. At highway speeds there should massive amounts of air running past the cooler. Did you install it RIGHT IN FRONT OF THE CONDENSER/RADIATOR ASSEMBLY behind the grille?

Tacey10

I have been towing in overdrive (the "D" position). I tried pushing the "tow button" on the instrument panel, but the tranny still overheated. I can try to tow in "3".
I had the tranny cooler installed by a local repair shop. They located it in front of the radiator toward the top. It is a "generic" or "universal" cooler, in other words, not the specific one as would have come from the factory.
Would I be better off taking the truck to the dealer?
Thanks for the reply!

Tacey10

I stopped in to my local Chevy dealer this AM. They printed off a build sheet. I have 3:42 gears. Would this cause me to overheat tranny? They seemed to think so, and also suggested to try towing in 3rd gear. Shouldn't turning on the "tow" button do this for me?

jlutty3

i have never had this problem on the flat in any of my Chevy's. It did happen to me in the hills on I-44 with a 2010 Tahoe pulling a car trailer with a 67 El Camino on it.

I would replace one quart of your trans fluid with Lucas synthetic transmission stuff- the thick, red stuff. or, dump in the lube guard additive.

Lucas will make it shift firmer and the Lube Guard will keep out air bubbles. Harder shifts mean less friction, heat.

I think your fluid is foaming and not carrying enough heat to the cooler.

Also, in hot weather, the A/C condensor will actually add to the problem by cooking that cooler from the back side. Is it touching it or is there an air gap between them?

Tacey10

The ATF auxiliary cooler is in front of the radiator, mounted near the top. It is mounted on an angle, that is, the top part touches the radiator housing, and the bottom is about 2 inches away from the radiator. It would appear to me that the angle would catch a good draft of air as the air deflects up off of the main radiator body.

Good point about the foaming. I did have the fluid and filter changed; the old stuff was black and thick. This truck was run hard by a utility company for 84,000 miles; I do not think they gave much thought to maintenance.

I also added some Lucas Transmission Fix. I will double check to be sure that I have the correct level of fluid.

I appreciate the feedback. I'll let you know how this turns out.

RacerX

Bull.....

RacerX

If the fluid was black and thick when you purchased it then its burnt up and no good, thats why its overheating. Time for a rebuild. I m thinking you are not towing in 3rd nor 4th(Overdrive). Your car is overheating because you are towing in 2nd. The tranny doesnt upshift past 2nd gear I ll bet. Additives are pointless at this stage because there is nothing to fix or improve on.

Save your money brother, this will cost you...about $2000.

Tacey10

RacerX have you got experience with this? I have talked to three service shops (two of them dealers) and none indicated that the tranny isn't shifting. I have told them all that I changed out black thick smelly fluid. Each of these places could do a rebuild and make $ off of me, but they didn't seem to be going there.

The truck seems to shift as it should when I am towing or not. I checked the fluid again yesterday and it is still clean after about 500 miles.

Yesterday, I ran it unloaded about 15 miles along a hilly route (I am in Pennsylvania) with frequent starts and stops. It seemed to run fine. I also ran it with the "Tow Button" engaged. The engine temp guage was around 185 degrees.

I appreciate the input. Something is up with this thing and I have to figure it out soon. I'll post my progress.

jlutty3

What would a guy possibly gain by fabricating a story about what he has seen on a transmission temperature gauge over six years (six trans fluid and filter changes) and 180,000 miles behind the wheel of a 2001 Suburban 2500?

"Bull" means lies. You might just disagree. I dont appreciate a stranger calling me a liar.