8.8 Gear Pattern


Jan 1, 2017
Hi all

I've been working on putting together a completely new rear end for my 04 and am currently at the stage of adjusting the backlash and pinon depth.

The axle housing I had purchased bare over a year ago (so no pinion spacers to compare with). The carrier I chose was the T2R (M-4204-T31H) with a ford performance 4.10 ring and pinion set (M-4209-88410).

As for the other hardware:
Axles (Moser Engineering A883153)
Ford performance ring and pinion kit (M-4210-C3)
Oil Slinger (Yukon Gear & Axle YSPBF-023)
2x C clips (Yukon Gear & Axle YSPCC-010)
Crush Sleeve (Yukon Gear & Axle YSPCS-002)
Reluctor ring (Ford part # F4ZZ2C189A)
Dust Shield (Ford part # E6TZ4859A)
Pinion Nut (Ford part # 389546)
Inner pinion Bearing (Ford part # 9L3Z4630A)
Outer Pinion Bearing (Ford part # B7A4621A)

The Ring and pinion set came with both a crush sleeve and Pinion nut, same with the Ford performance ring and pinion kit giving me 3 of each. I purchased an extra inner and outer pinion bearing for sacrificial pieces to help me get the proper pinion depth.

I also used the Ratech 10006 pinion depth tool to help me try to reach a proper depth, which after multiple attempts I finally think that I reached using 0.039" of spacers. At this point I have two concerns, my first is as per the ford manual the pinion bearing should be at 16-29 in-lbs of preload. At 10 in-lb I gave the tinniest turn and manage to bump it all the way to 29-30 in-lb. Is it ok for me to be at this slightly higher preload or should I undo it, throw in a new crush sleeve and go again? Second is that I noticed in a few guides it was recommended that silicone be placed on the teeth of the pinion gear when meshing it with the pinion flange to prevent oil from leaking by, I neglected doing this, should i be concerned?

Finally I get to the main point of this thread, here is the gear pattern I have with my current setup, using a dial indicator I am getting 0.0075" of backlash reproducible in 4 separate spots.


I painted them several times and ran them back and fourth with load on the ring gear, here is the pattern I think that I'm seeing (red shade).

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I just happened to find this thread, and I’m surprised you got no answers. I’m probably a little late as it’s two months later.
I just rebuilt my 8.8 (first time ever doing one), and from all the articles and videos I’ve watched, I think you look pretty good with the pattern.
I’d have to go back to my notes to see what the backlash spec is, but I thought I remembered 8 thou being the low end.
At .0075, I’d probably leave it.
Eric the Car Guy did a video series that was invaluable to me as I rebuilt mine, and definitely worth checking out on Utoob.