I have at least 1.5 to 2 inches of play in my rear diff. Have a bad feeling it may be the ring and pinion are worn or the crush sleeve is damaged. Replaced the U-joints, The slip is not in the tranny; with the drive shaft disconnected I can turn the rear diff 1.5-2 inches by hand. Recently had to replace the pinion seal as well. Ring and pinion replacement is the only thing that I can think of. Anyone have any insight???? It's a 8.8 with 4x4 auto locker, limited slip as well. Feedback is much appreciated.

 

"Inches of play"? Where are you measuring that? If you rotate the drive shaft with tranny in neutral and rear wheel brakes on, how much rotation do you get in degrees of rotation on the pinion. Up to 1/4 turn can be normal. There is also play between the axle side gears and the differential gears, beside just the play between the ring and pinion. Check play side to side on the front pinion companion flange, it should be zero. Pull cover off back to check inside, and you will se where your play is. Grab the carrier and pull side to side and up and down, should be zero play in the carrier bearings. Ring to pinion play should be about .008" to about .012".

 

With The Drive Shaft Removed, E-Brakes on, there is probably 45-50 Degrees of rotation in the rear end.

 

I can do almost the same thing in my Bronco. The reason you can too is your rear end is SHOT.

Just make it easy on yourself, and have the entire rear rebuilt if you can't afford to swap it out for a 9.75 rear. The 8.8s are crap. Complete crap.

I'm rebuilding mine. If you order your parts from Summit Racing online, you can get the TrakLok Carrier, the Ring and Pinion, and Master Rebuild kit from Ford Racing for just under $500. It includes crush sleave, ALL bearings, and all seals.

If you have it done, you will pay about $1000-$1300 depending on where you go.

There are some good websites that you can get a play by play at if you rebuild it yourself. But if you don't have the tools, take it in.

Swapping for the 9.75 would be the ideal thing to do, but it'll cost you.

 

Thanks Mach; I pretty much figured that it would be shot. I am more than able to rebuild it myself, just haven't had the time to get into it lately and wanted some input from you guys. My Engine is currently on the stand getting a rebuild, then it's the tranny's turn to get the extension shaft seal replaced as weel as a few other things. Then, if I am not poor, I will rework the rear end. I completely agree that the 8.8's are worth crap and am considering the 9.75. Will look at those parts you were talkin' about. Thanks again.

 

8.8 is crap? Tell that to the guys running stock 8.8 rear ends behind engines making 1,000+ hp and running sub 9 second quarter mile times.

 

OK. What's their phone number?

 

OSCA: Outlaw Street Car Association
Brian Keller: 1981 Ford Fairmont, 427ci Turbocharged Small Block Ford, Powerglide Trans, 8.8 diff (can't remember gear ratio) street tires, street legal
dyno tested over 1100 hp @ flywheel
sorry, can't give out his phone number