i have 1999 blazer LT and i have installed a 2 inch suspension lift and a 2 inch body lift.. now i ordered 31" tires to run under my truck with all the lift but im afraid the tranny might break down under the stress of the larger tires (stock tires are 28"). The car has 150,000 miles on it.. should i be worried about trashing the transmission with the 31's? HELPP

 

There is a lot of users on the forum running 30" and I haven't seen any of them mentioning anything about transmission problems.

 

If there are already problems with the trans such as slipping, the larger tires will magnify the problem. But if the trans is in overall good shape, having regular fluid changes through its life, probably once or twice at the 150000 miles you have, then you'll probably be ok.

But I would also keep in mind that 31's will make the truck signifiantly slower, so it will be tempting to drive the truck harder, which may contribute to a shorter trans life.