I have a 2006 uplander 3.5l 2wd 4 door LS. The trans went out and the only available replacement was out of a 2005 uplander 3.5l 2wd. The only issue I'm having is that there is a difference in the torque converter. The 2005 is smaller. My question is, is it ok to to bolt smaller torque converter in different holes in the flywheel??

 

Personally, I'd stay with the same sized torque converter.

 

Well that option is not available as I've already turned it in for the core. I worry about it changing the balance of the flywheel? Is this a real concern?

 

Yes. I must be at a correct balance, as are other parts of a motor vehicle.