3.94 final drive

[Campbell]

If I want to take a quaife with a 3.94 final drive out of a 4k and put it in another 4k tranny, do I need to switch the final drives or are they interchangeable? thanks

[67ITB]

from what I have been told by Dick Shine is that you need to keep "both" parts of the ring and pinion.

one is the large circular part that goes around the diff with like 67 teeth, and the other is the "shaft" (about 14 inches long) that turns off of it (it has like 17 or 18 teeth)

these parts must be kept together.

I have always done it this way and never had a problem

Hope this helps

Matt Bal

[Conover]

yeah keep each ring and pinion together with it's mate. It should have the bolt kit with a quaife, so shouldn't be hard to swap out ring gears if you need to. get a 4.25 they aren't that expensive, I can get you one for like $450 if you want it.

[racer_tim]

But it shouldn't be too difficult to determine which ring goes with what pinion. The teeth and slots won't line up on the ones that don't work.

It's kind of like wearing one blue shoe and one black shoe. To look at the positive side, you can say:

I have another pair just like them @ home.

[JamesB]

I am still not conviced a 4.25 is the right gearing for an A2. This weekend I had no problem moving forward with the 3.94 in my trans, suspension setup found me a consistend 1.5 seconds.

[Conover]

But it shouldn't be too difficult to determine which ring goes with what pinion. The teeth and slots won't line up on the ones that don't work.

It's kind of like wearing one blue shoe and one black shoe. To look at the positive side, you can say:

I have another pair just like them @ home.
[/b]

No, two 3.94's will fit together fine, but you need to keep each one with it's original mate.

[JamesB]

Cameron is right, if your talking about used R&P you need to match them. Even with with old is a bad idea as one will have wear and the other a fresh cut.

[racer_tim]

I was stating that a 3.94 ring won't work with a 4.25 pinion, and visa versa.