8.75 Question

[RAD1229]

  I have a 3.91 SG chunk that I would like to use  to make my 3.55 SG  is it possible to just swap the ring gear ??

[tactransman]

You would have to swap the pinion gear too,  you can't mix them up. Also they both have to be the same housing number (489, 742 etc.)

[ShelbyDogg]

But you can take the sure grip out of the 3:91s and put it into the 3:55 case and gears and vice-versa.   Don't touch the pinions at all and set the gear backlash with a dial indicator.

REMEMBER; 1. The ring gear bolts are left hand thread.
                2. When playing with sure grips, be sure to not lose the center axle spacers, or you'll never be able to set your axle end play.
 
Rob

[RAD1229]

Rob,

  SO you are saying I can salvage the suregrip gear (locker) from the 3.91 and fit it into the case with the 3.55's...  Are there anymore helpful hints about working on these cases, it would be my first.  Don't want to end up with nothing..

Thanks

[ShelbyDogg]

Tips? Yeah a couple more; 
When you take the bearing caps off, never forget which side they came from.

When you move the SG over, move the bearing races with the bearings they rode on.

Before you start, mount a dial indicator against one of the ring teeth, hold the pinion, then rotate the ring gear back and forth to write down the backlash. Install the sure grip and old ring gear back in, then adjust the side load adjusters to get the same reading.

Don't use a gasket on the 8-3/4 mount, only silicone sealer.