Hello all! I’m new here. Just purchased a 2007H3 with 75K miles. Needs a new tranny and radiator. Is this common? It’s getting worked on at the moment! I need advice on where to take it to make sure it’s safe to take back to NJ from Maryland. Thanks all!!

 

the radiators do fail in a matter that allows coolant to mix with the transmission fluid leading to transmission failure.

 

Yeah, at the same miniscule percentage rate 0.01% as all other GM vehicles with auto trans coolers running through them. Right up there with Lightening and Asteroid strikes.

 

Welcome. We would need to know why it needs a new Trans and Radiator.

H3 Radiators crack or can develop leaks at the plastic tank cap/base and aluminum heat exchangers. So do other GM Trucks of similar vintage. On rare occasions the trans coolers can leak allowing coolant into the Trans which is not good.

H3s have 4L60E Auto Transmissions, the failure rate is the same as they are in all GM trucks and depend upon use and maintenance. If you spring a Trans leak and just keep driving until all the juice spits out, you can toast it.

 

i understand it can happen to any GM vehicle but it seems that the odds seem to bend a bit more t'words the hummer lineup. H3 being affected a bit more than the H2. i am sure you can use the search tool on this forum to answer your question. it has been answered many times over. the data speaks for itself. or at least speaks for the loudest voices.

 

I was told I had a leak in the tranny cooling line. Next thing you know the car couldn’t go past 1st gear. Took it to a few places. I just got it from a dealer. Scam. I hope once they fix the tranny & radiator I don’t run into more issues. I’m also a woman & know just enough about cars.

 

Loudest voices. Excellent point. Go spend some time at the other more active GM truck Forums, it happens to Silverados, Sierras etc.... It is the complainers that post it, not those without issues. You do not see all the people that had zero problems posting how their Transmissions never got cooked by poor cooling within the Radiator with 100,XXXmiles. Not saying people are bad or have bad motives to post when something breaks.

BTW my Radiators never leaked into the Transmission on any of my GM trucks. There, subtract one.

 

I'm still driving with my factory installed(2006) 4L60-E. Still shifts like new!

 

and neither have stock OEM rads. need to be clear to your success.

 

Upper tank cracks/leaks due to the lack of mounting support(I've corrected/posted many years ago).Lower tank has plenty support where the transmission cooler is integrated!