Please Advise, Tranny Cooling Mod!

[Splashman]

Before I grew up to my H2, I had an H3. I had bad experience when tranny fluid line failed and mixed with coolant and was very costly. I don't want to go through that again. I'm in Norcal and it was 100 degrees on Wed last week. While driving home with A/C on low, I glanced down at gauges. Tranny temp usually a click below 200 degrees was right at 200, engine temp also usually a click below 200 shot rapidly up and over and seemed as though it would have continued had I not shut off the A/C as quick as I did.

This is what happened in my H3 when that problem occurred. I assume that when both tranny and engine get hot, the T-fluid and coolant expand which means increased pressure. This combined with weak spot in the cooling lines equates to line failure and it's all over.

It seems to me that due to the fact that I am on west coast, these cooling systems need to be independent.

If I install a separate tranny cooling system, i want to know recommendations. Also I am not sure how the new system would utilize he existing tranny temp gauge if it is possible.

Looking for opinions, recommendations and instruction from my Hummer Forum Generals!!!!

 

[hummech]

You are right to be concerned. If the coolant get into the trans fluid it can screw up a trans pretty bad and sometimes you will have to replace it. It is a known problem since 2003 and I don't believe anything has been up dated to fix it. I have install a few coolers and bypassed the radiator cooler which work great. I have also added electric cooling fans on them to aid in cooling better. The temp sensor is not on the cooler so that will not be effected.

 

[Chook]

There are lots of options for aftermarket transmission coolers & they are relatively inexpensive. If you don't have the skills/knowledge yourself visit an auto transmission specialist nearby that you trust (or trailer/towhitch installer if there isn't a transmission specialist)

 

[Splashman]

I wonder how many Hummer owners on this sight have installed a separate tranny cooler? The answer is all Hummer owners who are out of warranty! It seems to me that the stock cooling system has a high rate of failure and I can see this issue is a frequent topic of discussion on a few sites. Guess I have to do it as I am out of warranty. Any recommendations?

 

[06 H3]

I have an H3 and bypassed the the OEM trans cooler in the radiator. I like it because I dont have to worry about the exact issue your concerned about.

To avoid overcooling I put in an 160 degree thermostat.

 

[poncho1965]

Check out this thread for lots of good ideas!

http://www.hummer4x4offroad.com/forum/showthread.php?5423-Another-trans-cooling-thread


Mike

 

[amrg]

I just ordered this:

http://www.oregonperformancetransmission.com/mm5/merchant.mvc?Screen=PROD&Product_Code=LNG-49211

Its rated for a 30k GVW and has 34000 BTU cooling capacity. As they said, Im installing it seperatly because Im out of warrenty and Im worried about stock setup failure , otherwise I wouldve went with a smaller one in series with stock setup. This is the biggest I went with because Im worried it wouldnt fit (I have two electric fans plus stock clutch fan). The 40k version would be a nice addition, esp with a cooling fan. Its rated for 40k GVW and has 45k BTU cooling. Google tru cool 40k and u'll find full size pickups that installed it and are v. Happy with it!

 

[elkgrunt]

I just ordered this:

http://www.oregonperformancetransmission.com/mm5/merchant.mvc?Screen=PROD&Product_Code=LNG-49211

Its rated for a 30k GVW and has 34000 BTU cooling capacity. As they said, Im installing it seperatly because Im out of warrenty and Im worried about stock setup failure , otherwise I wouldve went with a smaller one in series with stock setup. This is the biggest I went with because Im worried it wouldnt fit (I have two electric fans plus stock clutch fan). The 40k version would be a nice addition, esp with a cooling fan. Its rated for 40k GVW and has 45k BTU cooling. Google tru cool 40k and u'll find full size pickups that installed it and are v. Happy with it!

I just put one of these in my 03 H2 this past weekend. I went with the Tru-Cool Max 40,000GVW and it fits great. I don't know how to post pics, so if you send me a Pm with your cell # I can send you pics of the installation. I quoted amrg because that is who I bought it from,http://www.oregonperformancetransmission.com/mm5/merchant.mvc?Screen=PROD&Product_Code=LNG-49211

 

[amrg]

I just put one of these in my 03 H2 this past weekend. I went with the Tru-Cool Max 40,000GVW and it fits great. I don't know how to post pics, so if you send me a Pm with your cell # I can send you pics of the installation. I quoted amrg because that is who I bought it from,http://www.oregonperformancetransmission.com/mm5/merchant.mvc?Screen=PROD&Product_Code=LNG-49211

Any updates on its cooling performane?

 

[elkgrunt]

Any updates on its cooling performane?

The ambient temp around here has been no more than 70 degrees, and the highest tranny temp I have seen is 105 degrees.Yes it is cooling great but the big thing was by-passing the radiator.

 

[twinmill28]

I'm driving '07 deuce and not worried about cooling problems at 68k miles--until I hitch the travel trailer loaded at 6.5k. My deuce has always been constant temp. on the road at any speed driving on it's own. When I hook up the trailer I run at great risk of driving up temps while towing at speed, esp. in the mountains when it's guaranteed to run hot unless I slow my speeds down. I've drive from Utah up into Canada, and from Utah into Vegas in the middle of summer, from Vegas to Phoenix, through Texas and into Florida in the hottest part of summer. I've done this with no additional cooling mods (though I highly recommend). As long as I was able to keep the deuce between 65 and 55 (yeah, slow on the interstate) and even slower when climbing hills, the temps stayed in acceptable range WITH the A/C on. We discovered you can run A/C towing trailer in the middle of the Nevada desert when the heat got too hot for my buddy to take on his portion of the drive. It's all about keeping the speeds down to keep the trans and engine temps happy.
Would I do this drive again without additional cooling? HELL NO!! I didn't add any tranny coolers as I figured I'd be pretty much flat towing here in Florida once we finished the move. It still runs hotter on the gauges if I try to bring it up to speed on the interstate, but I just back off and enjoy the drive.
Eventually it'll get a tranny cooler for my piece of mind and experiment to see how the temps fare.
BTW--I had my mechanic check all fluids once we got to Florida (diff, axles & trans) and he said they all looked good after that smoking 2500 mile run across the country--though I did smoke the famed exhaust manifold bolts to gain the notorious exhaust leak from hot engine for too long (separate issue).

 

[Zach]

The 2's typically don't have the issue the 3's have with radiators. They already have an external cooler that runs from the radiator to the cooler. Only problem with the radiator I've seen is the fittings will leak after time. Mine did that, simple fix was replace the radiator. I've never seen my trans temp up high. And have driven in extreme hear out here and hills. Goes up a tad, but not so much to be concerned.