I have been battling a shuddering problem after an engine and clutch replacement. I have been able to deal with the shudder by buring the clutch a little every 5000 miles or so and that seems to tame it, but when backing up in 4 wheel drive I get a real bad shudder that feels like the thing is going to blow up on me. It's the worst in 4 low as opposed to 4 high. Even if I rev high and try to engage it wants to shudder. When backing up without 4 wheel engaged there is a small shudder and it's not really noticable.

Anyone have any ideas?? My 93 F-150 supercab has a Rancho 3" lift so my drive angles aren' t the best but I have had the lift on the vehicle since new and only now at 130K is this become a possible problem.