Why does my transfer case keep going out?

I have a 99 silverado with the auto transfer case. The truck was damaged from a roll over when I bought it w/ 25K on it. The frame did not look to have been twisted. The truck sat square, and all but one of the bolt holes of the box matched up. One had to be bored out a little. It did have a bent rear axle and I replaced that. I never did a 4-wheel allignment on it. I had to replace the chain and sprockets in the transfer case at 35K. Now the truck has about 80K on it and the chain is slipping again. Another thing I see in threads is the question about "matched tires" what is meant by this? I have never replaced all 4 tires at once and never rotated them. Should I be more carefull with tire rotation and replacement? I am looking for suggestions before I rebuild the transfer case and end up doing it again 35K down the road.

I have a 99 silverado with the auto transfer case. The truck was damaged from a roll over when I bought it w/ 25K on it. The frame did not look to have been twisted. The truck sat square, and all but one of the bolt holes of the box matched up. One had to be bored out a little. It did have a bent rear axle and I replaced that. I never did a 4-wheel allignment on it. I had to replace the chain and sprockets in the transfer case at 35K. Now the truck has about 80K on it and the chain is slipping again. Another thing I see in threads is the question about "matched tires" what is meant by this? I have never replaced all 4 tires at once and never rotated them. Should I be more carefull with tire rotation and replacement? I am looking for suggestions before I rebuild the transfer case and end up doing it again 35K down the road.


first off these vehicles are to be not used in 4wheel drive on solid ,dry pavement, this includes auto 4wd....

when a 4x4 vehicle has differently worn tires, the drive train gets beat to death...proper tire rotation and all tires being close to the same wear will greatly reduce 4wd/drive train issues...

I rotate every 12-15,ooomi and the first set original lasted 90,ooomi...I now have 120,ooomi and the tires still look great.. Lt tires..


If you use this as a work vehicle you must service the drive train componets often...fliud changes and inspecting for fluid contamination etc......

"matched tires" is when all your tires are the same size on the front and back. you do know tires ware and get smaller as thay age.
if you only replace the tires as thay get damaged then you have 4 differnt hights on the truck from the frame. and it is giving you a twist on your trainy.

4x4 is very sensitive to tire sizes. by tire size i refer to diameter, not what you have written on the sidewall. if you have several tires worn differently, they are all of different diameter. it either locks front differential if used in 4wd mode, or, if difference is not so pronounced, puts a lot of torque on differential.
i'd safely assume 2 things:
1. your differential is than straining your transfer case
2. after wrack of such magnitude, you should expect all kinds of problems anyway.