sorry if this topic has already been posted but I have a 94 geo tracker 2dr w/auto trans. and 12 bolt rear  will the 3rd members (front and rear) out of a 90-91 tracker w/manual trans.
bolt in to my tracker? I am wanting to change to 5.12 gearing.

They'll most likley bolt in ok. I have a 95 Tracker auto that I put diffs (thirds) in from a 91 manual. Worked fine.

They will swap fine.  The only "issue" you may run into is the rear anti lock sensor in the rear diff.  If your stock third has an electrical plug/wire on it, then you need to be sure the replacement one does too (otherwise, the rear wheel antilock won't work and the brake light on your dash will be on all the time).  If your stock rear third doesn't have an electrical plug/wire on it, then the replacement third either can or can not have one (if the replacement third has one, you just don't plug anything into it and everything will operate fine).

thanks for the info I called hawks today and they are sending me the correct 3rd members.

thanks for the info I called hawks today and they are sending me the correct 3rd members.

Both front and rear?  For how much?

400.00 plus shipping for the set

400.00 plus shipping for the set

Ouch.