How easy is it to install 3.73 gears?

[stang_racer20]

Originally posted by crazypete
(warning! nonstandard methods below!)

IF and only if you get an FMS gearset, it's fairly easy. The ford gearsets are supposedly all machined to have the same depth. What I did was pop the back cover, take the retaining pin out. Then I put the car back on the ground and I used the resistence of the car and parking brake to hold it in place while I loosened the ring gear bolts. You have to lift the back end and rotate the wheels a few times to get them all. Then you pop the driveshaft and using a huge ( 1 1/16?) socket, go after the pinion bolt and remove it with the car providing resistence again. Then lift, pop the c clips and pull the axles. Pull the differential out and save the shims and remember where everything came from! With FMS gearsets, you can simply reuse everything (unless it's worn). Get a dead blow mallet and WHACK the pinion. It'll take a bunch of pounding to get it to come out. Have a shop transfer the bearing to your new gearset using the existing shims on the pinion and pound it back into the axle. Everyone will tell you to replace the crush sleeve but you need herculean strength to get the new one to crush. I reused the crush sleeve as well. Pound the ring gear off the differential and use the oven bake trick to get the new ring gear on. Loc tight it and replace it, push the axles back and reinstall everything so the car can hold the ipnion for you. Get your pinion nut and tighten it till you have elimanated the wobbling effect and get ready for a hernia. Tighten it until it feels solid and gives a light resistence when you try to spin it. This will take at minimum a breaker bar. Reattach the driveshaft and take it for a careful spin! Problems will show up on deceleration. The only variable here is the pinion nut. If it howls, tighten the pinion nut till it goes away. See? No tools necessary. I used this method to go from 3.08 to 3.73 and have been driving around since last september on them with no noise whatsoever.

u had it mostly right except for checking the backlash and wear pattern which is the most critical part. yes the original shims for fms gears should work(they did on mine), but make sure they work before you drive it! And just a word of advice for you crazypete, not replacing your crush sleeve was a BIG no no! You'll see the difference in the long run when your gears bust within a few years.