Its a 91 full size blazer. Within the past few months a I had a new Transmission mount put on. I've always had the clunking for a while, and yesterday changed all the u-joints in the front and rear drive shafts. Theres still the clunking when i go into drive and reverse, and I'm so confused. What else could it possibly be? It's not too loud anymore, but still very noticable. The truck also jerks a bit.
What may be making my truck clunk when I go into drive/reverse?
U-joints were my first thought too. Check your motor mounts, transmission mounts, and drift bearing on rear driveshaft if it has one. Some GM trannys need additives poured into the ATF. Your torque converter or some solenoid that operates it may be wearing out. AAMCO can diagnose it for cheap.
If you park on a hill without engaging the parking brake, the tranny will clunk when it shifts out of park. That's an easy fix and test.
What may be making my truck clunk when I go into drive/reverse?
could have a bad motor mount. or what i have seen is the rer end has a bunch od play in the ring and pinion would cause the loud clunk. if the trans shifts hard this will cause a jerk and clunk due to the rear end play.
Check the motor mounts, they could be worn or loose.
This vehicle has 4 wheel drive, you said it has a transfer case. I would check the CV joints in the front end
1 tranny problem
2 idle too high [tuned up?]
3 engine mount..
the idle could be high like the other guy said previously. there is probably a lot of back lash in the rear end that is not easy to remedy
it could be slack in the ring gear or the nut behind the back u-joint is loose. the nut holds the pinion gear tight.
