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Last spring when I was "working remotely" I decided it was a great time to repair all the rust on the truck and make a few other modifications. I have an '86 F250 with a Sterling rear end that was initially set up with 4.10 gears. A number of years back I picked up a used 3.55 Limited Slip and I am finally getting around to putting that in while I have the bed off and everything cleaned up. There is a lot of great advice and info on this site and internet, I am pretty confident I am close but the actual pattern is not quite exactly as commonly pictured - maybe it is due to the used gear set? The first pic was the pattern with the a .020 pinion shim (close to what was in with the 4.10 set. It looked like it was riding high on the tooth so I increased to .026" and the second and third pics are the drive/coast patterns for that, maybe not perfectly centered but is it acceptable? Or is it worth the effort to pull the bearing off and maybe drop the shim thickness slightly to see if it will center better between the heel and toe? (I had the backlash for both set at .012/.013" and I have all new bearings on the carrier/pinion) This is the first time I am working on a diff for me so I don't have any prior experience to rely on. Any advise would be most appreciated -thanks!
Pics 2 and 3 for a used gear set, is pretty much perfect.
OK I will run with it as is. Thanks for the feedback, I was probably over thinking it and trying to be too precise with getting the pattern centered. In hind sight I should have looked at the contact pattern for the factory set before I pulled it out first.
Now I can start putting the back end of the truck back together...
Phil
I was probably over thinking it and trying to be too precise with getting the pattern centered.
To set up differential gears, you’ve got to juggle three things:
Drive pattern
Coast pattern
Backlash
Changes to one will affect the other two, which can be frustrating. You’ll almost never get all three absolutely perfect. I’ve always favored the drive pattern and been okay with an acceptable coast pattern, while keeping backlash within specs.
