View Full Version : 3.73 ratio question

06-09-2005, 05:45 PM
Hello, i want to change my 91 auto. SCs rear differential from 3.23 to 3.73. I would do it myself to save money and was wondering how much parts would cost, what all i would need and even more important some info. on how to do it. Step by step instruction would be what i would probably need. I really have no idea how difficult or easy this project will be. There is nothing wrong with my differential now but would like the 3.73 for street racing reasons. I assume for a few hundred bucks it would be the best bang for the buck. Would i have to pull the axles out to do it?
Info needed and appreciated.

Scott Long
06-09-2005, 07:14 PM
You have 3.27's in yours.

You need a ring and pinion set, cost around $160. Can find on ebay, or many online stores. Just order one for a Ford 8.8" rear.

As for setting them up yourself, its not recommended. Unless you have extensive mechanical knowledge, I'd leave it to the pro's. You have to shim and set the proper backlash and measure tolerances. If its wrong your gears will whine and howl.

You could take the rear out of your car by removing the driveshaft, axle shafts, and mounts. Then take it to a shop and have them set up your gears. Shouldn't be too much that way. I had a shop do mine including dropping the carrier and reinstalling it. Cost me around $400 for labor plus $160 for parts. Pricey.

06-09-2005, 08:38 PM
Perhaps one of these if it has 3.73 gears in it.
Differential, Traction Lok, Limited Slip, 28-Spline, Ford, 8.8 in.
This way it is all preassembled with new clutch pads:


06-09-2005, 09:20 PM
I took my 94' to a pro. I had 3:73 gears installed, track-lok, and a full rebuild on the pumpkin. Labor and parts ran around $1100.

06-09-2005, 10:25 PM
thanks fellas, thats pretty much all the info i needed.

big ed
06-10-2005, 03:16 PM
Why not call Maxx at Five Star Ford; 1-800-866-1520 x 236. Better prices & consistant service. Ed :cool: