vibration in drive line

**groundedGMC** · 01-24-2009, 07:35 AM

Hey guys I have a 1997 GMC extended cab and put a 4/6 drop on it. I put the carrier bearing spacer kit on. I had to use both plates under the carrier bearing. I still have a vibration from about 45 mph and up. I have had my wheels rebalanced numerous times. The vibration will stop or almost stop when i let off the throttle at those speeds. I looked at the drive shaft while on a lift. From the rear end to the carrier bearing it is angled down pretty good. I dont know what angle is though. I have heard the drive shaft is suppost to be as straight as possible from the rear end to the transmission. But I have also heard if you install the carrier bearing kit it should fix it. Please help me i am stumped and want to fix the problem. Oh just in case the vibration did not start until it was lowered and the carrier bearing and ball joints appear to be alright.

**flotsamm** · 01-24-2009, 09:21 AM

Most of the time its the pinion angle that needs adjustment. Maybe install some angle shims and see if that fixes it.

**someotherguy** · 01-24-2009, 09:53 AM

What flotsamm said.

Which brand/part # kit did you use? The good extended cab kits come with pinion angle shims, as well as the carrier bearing and transmission mount spacers.

Richard

**groundedGMC** · 01-24-2009, 09:57 AM

I have the DJM kit and there was not pinion angle shims in the kit. It is just adjustment of the axle and how it sits in the flip kit. The carrier bearing kit just came with two plates and two bolts to stick under the carrier bearing. if it is a pinion angle adjustment do you know what angle it is suppost to be at.

Thanks

**someotherguy** · 01-24-2009, 10:01 AM

I was just talking with another guy using the DJM kit and he's having a bunch of trouble with it. I use BellTech, they have the shims. I think DJM used to do the shims but now have that supposedly adjustable thing.

Anyway he said that once he'd get his adjusted, once he jumped on the throttle it would just move back.

Richard

**flotsamm** · 01-24-2009, 01:39 PM

Originally Posted by groundedGMC

I have the DJM kit and there was not pinion angle shims in the kit. It is just adjustment of the axle and how it sits in the flip kit. The carrier bearing kit just came with two plates and two bolts to stick under the carrier bearing. if it is a pinion angle adjustment do you know what angle it is suppost to be at.

Thanks

Two to four degrees total should do it.

**jolt11** · 01-24-2009, 04:13 PM

Same here, I ordered a McGaughys flip kit and I'm goin to get some shims. I have a DJM on my OBS Ext. Cab right now and I can't get my pinion right with for crap.