Well today my pinion bearing started whining while coasting. It only makes the noise when the transmission is in gear and only while coasting/engine braking. It's quiet while accelerating or coasting in neutral.

My next door neighbor (a mechanic of 20+ years) took a short drive with me around the block and listened to it (he was the one who told me it was the pinion bearing). He said that the most likely cause is the new LSD carrier I installed back in January is still "breaking in" and the pinion bearing preload is now out of adjustment. His suggestion was for me to tighten the pinion nut in small incriments and test it and repeat that process until the noise goes away. Then he said if it doesn't, the pinion bearing is shot and needs repacing.

Does anyone have any thoughts on this?

 

It may be out of adjusment but I never realy heard of it doin that. But Im still new to this all compaired to a 20yr mechanic. How are your U-Joints. Are they new from your swap? Is your rear end oil good? Any leaks?

 

Yeah, I should have added. When I did the rear end swap, I had to replace the yoke, which required removing the pinion nut. I installed it to exact factory torque, and hadn't had a problem with it since until now.

U-joints are brand new. For the rear end oil, I have straight Lucas Oil Additive and LSD friction modifier that was put in last January when I did the LSD swap. No leaks.

I'm hoping the pinion bearing is not shot, cause I'm not looking forward to having to replace it!

 

When you replaced the yoke did you replace the crush sleve? It is only good once.

 

I did not. I'm not sure what a crush sleeve is.

 

I'm almost positive the 9.25 has one because both axles work the same just its bigger. The crush sleeve is on the pinion. It is a sleeve that gets crushed as you tighten down the yoke. It keeps the correct spacing and preload on the pinion. It replaces shims on the pinion after the bearing on other axles. It can only be crushed once. If done a second time it will crush some more and give the incorrect spacing.

When I did my gears I bought 3 extras Just incase. I think they were under 6 each. Check with http://www.ringpinion.com/ they have it listed in the kits but call them up I know you can buy it separately.

 

Interesting! I guess on my way home from school tomorrow I'll stop by the store and pick up a new crush sleeve and try fixing it. Can you think of reason it would have taken almost 5 months to start acting up?

 

Copied from the page 8 of Rear Suspension and Axles in the FSM...

This describes the problem very well.

 

Cool sounds like you found your problem. Order up ring and pinion kit and replace the other bearings as well. Now the fun part take apart the ring and pinion and install it. Have fun!

 

Lol, the carrier bearings are brand new! I had them pressed on when I got the LSD. So that just leaves the pinion bearings. I'm still going to try and adjust the pre-load, but if that doesn't work, I'll order the pinion bearings and swap them. If it comes to that, I'll write up a good post for anyone who wants to do an R&P install cause even though I'm not changing them, the process is probably the same!