Has anyone put an aftermarket Tranny/Oil cooler on there H3. I will be towing my 3500 lb boat this summer locally. I don't anticiapte any 500 to 600 mile road trips pulling my boat this summer. But I want to make sure that the H3's TrannyFluid andoil doesn't takes a beating in the summer heat.I just want to know if anyone can recommend a particular company that sells a good after market cooler for the H3. I would appreciate any info anyone can provide.

 

I am assuming you have an Automatic Tranny, if you have a standard your out of luck.

Basically you will be taping of your radiator tranny"RETURN" line is the best way to go and will be adding a little more tranny fluid. Make sure you reallycheck before you finally do this because if you start cutting tranny lines etc... it can get messy.


http://www.tciauto.com/Products/Cooling/

http://www.bmracing.com/media/catalog/9.pdf

http://www.haydenauto.com/products/t...il-coolers.htm

 

Correct me if I'm wrong but I think the only time you'd really need a tranny cooler is if you were towing a lot in stop & go traffic as that's when your transmission is most likely to over heat. But I suspose it's better to be safe then sorry. Just a thought, does your boat trailer have brakes on it?

 

I thought the Alpha's had a tranny/oil cooler. I see a small secondary radiator that is located under skids just behind the main radiator. I thought thats what it was.

 

I've looked on my window sticker and I don't see any mention of a tranny/oil cooler. I also looked on the Hummer site and cannot find a tranny/oil cooler offered even as an option. All that is mentioned about the transmission is that it is a Hydra-Matic 4L60-E 4speed Auto (standard on the H3 Alpha)

 

I looked on gmpartsdirect.com and they have a listing for a transmission cooler for the I5 (no part # or illustration). I didn't see any Alpha parts so I can't comment directly but it would seem that the Alpha would have one if the I5 has it.

 

I haven't added one to my Alpha but I did put one in the wife's Covette which just happens to use the same 4L60E tranny the Alpha has. I installed a tranny cooler in the vette because I swapped in a hig-stall torque convertor along with 3.42 gears and it was a requirement for that setup. The tranny temps can be monitored directly on the cars Driver Information Center display on the dash and stay in the 150-190 deg. F range even in the 100+ deg. temps we had here last summer.

This is a dedicated tranny cooler so I would need to swap in a Dewitt's EOC-style radiator or a custom oil cooler if I were to go that route. I've seen some trick custom oil cooler setups on vettes but they are a bit more involved than a tranny cooler due to the adapter required to tap off the block. Dewitt's offers combo EOC/tranny cooler radiators for several cars but I have no idea if they offer a Hummer version. Tom's rads are trick and work extremely well.

The cooler I installed was an off-the-shelf Hayden that I plan to replace with a heftier B&M.