Differential gear swap

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May 25, 2009 | 08:00 PM

thiatt

Thread Starter

Instructor

Joined: Oct 2008

Posts: 176

Likes: 1

Differential gear swap

I'm going to change the ratio on my '77, from 3.08 to 3.70. Will I need a new "posi" pack or are these the same? Also if they are the same, can they be rebuilt for cheaper than new? Any other advice or know how is much welcome. Thanks

May 25, 2009 | 08:08 PM

bernie payne

Instructor

Joined: Apr 2008

Posts: 190

Likes: 0

From: Melbourne FL

I am getting ready to do the exact same thing on my 76, and I am not that sure either.

May 25, 2009 | 08:35 PM

Grumpy 427

Melting Slicks

Joined: Oct 2008

Posts: 2,154

Likes: 69

From: Regina Sk Canada

No you should be fine. Its when you go to a 4 series gear that you need a to go to another posi carrier. I think its Richmond that makes a 3.73 gear to fit where a 4.10 gear used to be. So thats the only one i know of that is swapable in that regard.

May 25, 2009 | 08:38 PM

Gordonm

Race Director

Joined: Dec 1999

Posts: 19,610

Likes: 778

From: Forked River NJ

All the 3 series gears will fit a 3 series carrier. There are some gear manufacters that make 4 series gears fit a 3 series carrier. You cannot make a 4 series gear fit a 3 series carrier.

Yes you can replace the clutch packs, beware of the cheap ones, they are not good and will self destruct. If you need info on the rebuilding contact Gary gtr1999 here on the forum. He is the expert. I have done a few myself but he has done many.