MTFCA Forum

Rebuilding a rear end and would like some help to determine if this ring gear would be useable.
Thanks
Rick S.

You are not showing the drive side of the gear. Wear on the back side dont mean much. If the other side of the gear teeth are nice - go for it.
That gear could have come from a modified to trailer rear end.

Yes! It looks practically brand new.

Both sides of gear look identical
Thanks guys for the help

A ring gear that good is rare. It is worth setting up well. The second photo shows polishing typical of too much baclklash, which means the ring gear needs to be moved closer to the pinion to get the correct rolling fit.
You can get less backlash by moving the driveshaft aft a bit, but that will not give the correct rolling fit on the full width of the teeth. For best results, the diff centre needs to be shifted so the gears mesh deeper. That will mean juggling the steel thrust discs and the bronze thrust washers.
No doubt this was not done in the factory, as it is a time consuming task, but is can be done with patience.

Allan from down under.

Absolutely agree. I've got at least 2 dozen used ring gears and none look that good. I recommend setting things up on the loose side. The quietest rear end I've rebuilt had 15 thou lash.
Thank God it's one I kept. It's under the 12 now.

When setting up the gears, do not focus on backlash. Focus instead on proper contact between the teeth of the pinion and ring gears. Once you have a good contact pattern, and a smooth mesh, your backlash will take care of itself. Once you have good contact and smooth rolling don't fret if the backlash is not what you thought it should be, as long as it's not a tight mesh it'll be fine. Too many people focus on backlash only and think they've got it done. It's possible to achieve a desired backlash and still have a lousy mesh.

What Jerry said. With the correct rolling fit, there will be contact between the gear teeth right across the teeth. That rolling fit is achieved by correctly centering the diff inside the housing. As he said, getting that right will take care of backlash, which may well be more than is expected.

Allan from down under.

Absolutely agree re tooth contact although I still think a loose fit is best. Been there many times.