rear end rumble

[CJJay]

I took the cj3a for a ride to today and every time I let off the gas there is a loud noise and rumble that sounds like it comes from the resr end. any thoughts, I put ndw bearings and races in it.

[bretto]

ujoints?

[F Bill]

Jack it up and check for play in the pinion shaft....How did you set the pinion bearing preload?  Is it possible the nut holding the yoke on has loosened??

[CJJay]

I wish, I just pulled it apart, cleaned it, replaced the races and bearings and put it back together the way it came apart. I'm going to replace the ujoints first and see if the yoke will tighten down more before I start over again.

[bretto]

Did you check the gear mesh pattern after changing bearings?  The gears could of been quiet with the old bearings and now with new, they could not be meshing right.  Might be close but not enough.  Did you change all 4 sets? (both pinon and both carrier).  And why did you change them anyway?

[rocketeer]

I wish, I just pulled it apart, cleaned it, replaced the races and bearings and put it back together the way it came apart. I'm going to replace the ujoints first and see if the yoke will tighten down more before I start over again.

Did you follow the procedure in the manual? Did you pre-load the pinion? Once you change bearings you have to go through the entire procedure of checking pinion depth and ring & pinion lash plus gear mesh, otherwise serious damage can be done.

http://www.vernco.com/RearAxle5/index.htm







Larry

[rocketeer]

Larry

[Bob W]

Driveshaft u-joints in phase?

[CJJay]

I replaced the bearings because they were shot. I have read vernco pages twice and still am a bit imtimidated about how this all works. Tonight I went out and disconnected the drive shaft at the differential and although I have no vertical play,I have a lot of rotational play which means the pinion is not messing with the ring gear at the correct spot. The next question is can I fix this with out pulling the axles and pumkin.

[bretto]

Sounds like you have too much backlash. �I bet your mesh contact is way off. �I wouldn't drive it anymore till this is fixed, you can burn up your gears. �Unfortunately, to do any of the adjustments, you have to have the axles out. �You sound adventurous enough to learn how to do this, it just take a�certain amount of reading up and getting the right tools to dial it in. �You need to read up on this.
Years ago I found this info helpful:
http://www.ringpinion.com/Content/HowTo/TechnicalInstructions/Yukon_Installation_Kit_Instructions.pdf
There is some good info @ Randy's Ring and Pinion and Yukon Gear & Axle sites to.
Brett

[CJJay]

I totally disassembled this axle and replaced all the pinion and wheel bearings last summer. I just didn't replase the shims or understand this adjustment correctly so I guess I have to try to pull everything with out loosing any brake fluid and rebleading the break system. Do the shims at the wheels effect this as well?

[rocketeer]

As long as you reuse the exact same shims at each axle end there should be no problem.

Larry

[CJJay]

the problem is I'm not sure if I did replace thew shims as they came out. I cleaned it all and then re assemblemd them and it is more than possible I have more shims on one side than the other or I have miss balanced the correct amount foor one side. If there is 5 shims on one side an 2 on the other (on the out side not next to the differential) this make one axle farther away from the pumkin than the other, correct. If you change these shims around does it change the distance the rack gear is from the pinion or just the location of the splines on the end of each axle. In other words can the shims that go on the axles by the brakes effect the backlash.

[bretto]

The axle shafts and outer shims have no effect on the carrier to pinion set up.

[rocketeer]

Those axle end-play shims have no effect on backlash.

Larry