How do I identify which ring and pinion Is in a diff?

[nemick]

I've bought a used diff as a possible replacement for the stock one in my 2001 A4 TIP. How can I find out what ring and pinion are n the replacement without taking it apart?

Thanks

[Bordom]

Just replace it with the new one. Why bother taking it apart?

Everything graciously mispelled by Android

[nemick]

Because I don't know for sure if the replacement has the same ring & pinion ratio.

[vrmm]

Well... You could try the good ol' spin method..

"One somewhat easy yet very reliable way is to jack up the wheels, disconnect the driveshaft, rotate one wheel, and count how many revolutions the pinion yoke/flange makes."

Based off of that you can get a ratio....

[vrmm]

There's lists out there to decipher amount of rotation into gear ratio. It'll be for 4x4 trucks and the likes for the most part.

[redline380]

Well, it should have a code stamped on it somewhere

[walky_talky20]

Yep. Just read the code. Then AZ members will decode it for a small fee. ;)