I had a u-j squealing on my main driveline and when I was replacing it I noticed that the the yolk at the companion flange has some slop in it. ( This is the second uj in 5 years on this shaft) I became concerned after reading over pinion threads in this forum. To be safe I drained the diff (dana 8.8) and removed the back looking for shrapnel, metal grindings or any evidence of a problem other then the slop in the yolk and found none. With the cover off and the truck on jack stands I put the tranny in neutral, (mdo5 manual), and spunn the tire watching inside the diff as the ring gear spun. I couldnt see anything that looked out of the ordinary so I cleaned up the cover, scraped the old gasket off and re- sealed it. I waited over night before refilling with gear oil.

I called my local mechanic for a referal to a diff repair guy and called for a price on front and back pinion bearings. I asked him questions to see what he would say about pre-load and picked his brain concerning how he would do the repair if I needed it done. He gave me a ball park of 450$ for front, back and seal on the pinion.

Do I need this repair? Is 450$ in line? Any thoughts on my issue would be greatly appreciated!

 

Just make sure your pinion nut holding the companion flange is tight. Mine was 1/2 turn loose. Usually this or other pinion problems cause a whining noise...When I tightened the nut the whine stopped....

 

What do mean by slop, up and down or rotation?
If it is rotation than you are talking about backlash, backlash is adjusted by the side shims.
If it is up and down you need to tighten the companion flange nut until you have about 11-15 inch lbs. of force to turn the companion flange with the drums off.

 

With the truck in gear and parked I can move the drive line a little at the rear u-j and the flange moves up down , side to side. Not what I would call a bunch but it does seem "sloppy" as I would expect it to only rotate. There is some backlash as well. I can rotate the shaft and there is some delay before the tires turn. When it was up on jacks I noticed that when I turned the tires with my hand and reversed diredction there was some backlash before the shaft in turn changed directions.

 

I don't know how to answer other than telling you that the backlash between the ring and pinion should be between .008" and .012" to be correct. The other thing I would tell you is that the 8.8 is crap. Very common axle, but crap. I'm about to rebuild the one in my Bronco next week. Someday, when I have the time, I'll swap it out to the 9.75 or something.

How many miles on the truck? If you're over 100K, you might consider rebuilding it also. They're crap.

 

I just put all new bearings in an 8.8 this past weekend. One of the carrier bearings was very rough. But I didn't understand when my instructions said the pinion nut should be around 15 in lbs. I had a breaker bar on it turning the nut and I still had slop in the bearings, but just as I read your posts, you guys are talking about the 15 in lbs being the resistance in the differential. Is that right? Not the tightening of the nut itself.
And another thing. When I pulled the diff out, it had one fairly thick shim on both sides of it, and when I went to put it back together, it was a lot tighter. It all went together, but I just didn't want it to have too much resistance. any thoughts?

 

You needed to put a new crush sleeve on pinion shaft, use a large breaker bar to start the crush of the sleeve then using an inch-pound bending beam torque wrench on the pinion nut rotate pinion shaft looking for that 15 inch/lbs. If not enough crush somemore. If too much start over with new sleeve. There is much more to the gear setup than this. You could search on Ford 8.8 on yahoo or go to www.fullsizebronco.com and search.