Radiator Warning!!!!
 

I recently had my transmission cooler in my 2006 H2 fail and it wiped out the transmission plus having to replace the radiator,waterpump,all hoses,etc...
A very costly problem. I cut open the old radiator and gained access to the failed cooler and found that the case of the cooler was slightly bulged out
opposite the intake port and the center of that hump had split open about .08 of an inch and I see no signs of any corrosion anywhere.. I am now of the opinion that the service life of these GM radiators should be limited to 80 or 100
thousand miles before replacement... $150 - $160 for a radiator is cheap compared to a trans rebuild.. I had 106,000 miles when this happened..
A few notes:
I found that not stopping completely in reverse before shifting to drive will eat
up a drum in the transmission by digging grooves in it....
Also I rebuilt my transfer case and found 2 bad roller bearings that were making
metal.. My case shifts incredibly smooth now compared to popping when it shifted before the rebuild....
My H2 has always had DEXCOOL in it and I see no signs of any reason to change that contrary to some posts about it causing corrosion.... Cheers.

Re: Radiator Warning!!!!
 

This is a well known defect and is the reason so many have by-passed the stock cooler altogether with the addition of an External Tranny Cooler.

It would be great if you would post some pics of your failed cooler!