My bet is that the backlash was not set at the same spec as it was before they yanked the open carrier. They should have measured backlash at 3 or 4 locations around the ring gear, averaged it, then reset it with the ring gear bolted up to the LSD. Also will get gear noise where none was before by not thoroughly cleaing the areas where the ring gear seats on the carrier and the back of the ring gear. If any debris is stuck in there, it can slightly warp the ring gear enough to cause gear noise.

Unfortunately, you probably don't have a good measurement of backlash before dissassembly. Can't really used the FSM figure as that's for new gears. I had to yank one of my diffs three times to trial and error the backlash and get rid of gear whine. I thought I was going to save time by having a "gear expert" set it up for me. But I had to completely redo it without the original backlash figure. Finally got it right by setting towards the loose side of the FSM range.

Gotcha <img src="/forums/images/graemlins/cheers.gif" alt="" /> Thanks,

I trust Phil, and if he sais it was ok before, then it was OK before.
I'll get to the bottom of this - I got mud to run !

-A

What gets me is why they didn't replace the third member? Its a literal boltup, even for a non-mech type like me.

Good luck Drew, and keep us posted.

PHIL

Just one more question to add: Did they mix up the ring and pinion gears or did they keep them together as a set? In other words, did they use 'Phil's' ring gear (and LS unit) with the pinion gear from the open diff?

Maybe I misunderstood the earlier question, what you sent me Phil, they installed. My apologies if this is considered the "3rd member"

Here's a pic: ( Of the open diff they took out )

web page

I also checked as per Big Blue by getting under the rig and turning the driveline. I have 1/4" of movement +/- 1/32"
Sounds like that is unacceptable.

Update: Tow truck guy just came and took it off to a recommended drivetrain place. They're going to diagnose and call me back. Suggested it may have "dried out" from sitting waiting to install- and disagree that it couldn't be caused by pinion bearings as, in there oppinion, the bearings would whine both loaded and unloaded which is what is happening.