I have found a 2005 GMC Sierra with the 6.6L duramax. It has a 6" lift with 20" rims and 35" tires. They are asking 16,000$. Now I love all of that but it has 160k miles....which scares me, I have never owned or known anything about diesels or the allison transmission. Can anyone tell me the average life and if this is worth it?

 

sounds like a decent deal, as long as the trucks in good shape...
figure out what problems the truck has previously had..
160k miles is like a middle aged adult, still got plenty of life in it

 

160k miles is just barely broken in if maintained right. if it was in good shape i would jump on it

 

id get under the truck and check and see what kinda mud is inside hidden place like the lips of the frame. if the truck has been in a lot of mud i would be leery of buying it because that leaves the possibility of some abuse.

 

good info here.

these trucks can go 500K+ miles if taken care of. since the previous owner had put a lift and larger tires on it, there is the increased risk of abuse. as DirtynessMaximus said get under the tuck and look for the signs. dried mud, rust, rotting bushings, ripped boots, etc

on the other hand it may have been just for show and still be in excellent shape.