Forgive my ignorance as I do not pretend to be a mechanic of any kind.
I have received different answers from different people and am hoping you guys can clear something up for me.

I have an 07 H3 with a cracked transmission case.
The specs say the transmission is the 4L60E. A search for this says that this transmission has been used on a plethora of trucks and cars readily available at any junk yard. I have been told that there may be differences in the transmission depending on what vehicle it was in even if it is still a 4L60E.

Is this true? Or would any 4L60E work in my H3

 

No, just any 4L60E will not work! You need a 4L60E from a five cylinder hummer (the ALPHA uses a 4L60E but the bell housing /torque converter is different). The HUMMER tranny is different from the "generic" GM 4L60E........pan for clearance, valve body, etc..

 

for all usa junkyards enter car-part and follow instructions.