Screwed up my rear gear install, need opinions

[RedVenom48]

Screwed up my gear install. Long story short I used a solid pinion spacer rebuilding my GT500 rear end. Shimmed it and got the correct preload that I was looking for with the bearings. It was later in the day when I got to that point and I wasnt thinking correctly. I didnt torque the pinion nut to 140 ft lbs... its preload tight but not torqued tight.

I drove the car about 60 miles mosty freeway with the last 10 miles on city streets. Light acceleration. No real noise from the rear end... was actually silent for the first time in a while. At the end of the drive home I did notice a whine on decel. Its what got me replaying the install and realizing my mistake. Im parking the car till this next Saturday when Ill be able to work on it again.

Do you think I messed the gears up? No hard acceleration, just 60 miles on the freeway.

Im planning on pulling it apart and replacing the pinion roller bearings and starting again. Can I get away with just replacing the tapered roller bearings or will I need to replace the races too?

Ive been a professional wrench for 10+ years and this is honestly embarrassing... first time rebuilding a rear end though. Either way, Im just happy I realized it this morning when my brain wasnt mush.

Any advice is appreciated.

 

[50stangpower]

Not sure I can help you but stuff happens all the time. At least it's not catastrophic.

 

[avgt500]

I also used a solid spacer instead of the squash washer, set everything to within .001 and have a slight noise, FMSS fears, second set, first one they missed tapping one ring gear hole, going to upgrade to 33 spline axles and tru track soon, still researching what gears I will use but they are not going to be FMSS gears.

 

[biminiLX]

I think you'll be fine buddy. Just recheck and torque. Worst case it whines but nothing you can do at this point.
-J

 

[RedVenom48]

I also used a solid spacer instead of the squash washer, set everything to within .001 and have a slight noise, FMSS fears, second set, first one they missed tapping one ring gear hole, going to upgrade to 33 spline axles and tru track soon, still researching what gears I will use but they are not going to be FMSS gears.

I cant recommend enough the Ford Racing gears. Even with my mistake, i literally swapped the same pinion shim and the diff carrier shims and my backlash and pattern were spot on.

 

[biminiLX]

Agreed. Go Ford gears every time. Good idea on solid spacer too.
-J

 

[MG0h3]

If the nut didnt work loose youll be fine. Just torque it down and go is what I would do.

 

[98-svt-stang]

Agreed. Go Ford gears every time. Good idea on solid spacer too.
-J

I kept hearing that after I had already purchased my motive 4.30 gears. But I decided to go ahead with my install anyway. I just reused the stock pinion shim and set backlash 10 thousandths. My pattern looked good to me. So i went ahead and set pinion preload with a new crush sleeve. I have no whine whatsoever.

 

[gimmie11s]

I cant recommend enough the Ford Racing gears. Even with my mistake, i literally swapped the same pinion shim and the diff carrier shims and my backlash and pattern were spot on.

I just finished mine as well. The idea behind the crush sleeve for the pinion is to torque the nut down JUST far enough for the outer pinion bearing to fully seat. You can feel it when it happens. Ive never used a solid shim so no experience there for me.

Ive done 2 of these now and youre right, the ford gears set up damn near perfect with the exact shims that came out of the car.

That said, if you are only going up or down 1/2 a rotation or so (I went from 3.31 to 3.73) there wont be much change.

Guys going from 3.31s or longer to say, a 4.88 or shorter, are likely going to have a bigger chore getting it all to dial in.

I kept hearing that after I had already purchased my motive 4.30 gears. But I decided to go ahead with my install anyway. I just reused the stock pinion shim and set backlash 10 thousandths. My pattern looked good to me. So i went ahead and set pinion preload with a new crush sleeve. I have no whine whatsoever.

looks good for coast, what does the drive side look like?

 

[98-svt-stang]

I just finished mine as well. The idea behind the crush sleeve for the pinion is to torque the nut down JUST far enough for the outer pinion bearing to fully seat. You can feel it when it happens. Ive never used a solid shim so no experience there for me.

Ive done 2 of these now and youre right, the ford gears set up damn near perfect with the exact shims that came out of the car.

That said, if you are only going up or down 1/2 a rotation or so (I went from 3.31 to 3.73) there wont be much change.

Guys going from 3.31s or longer to say, a 4.88 or shorter, are likely going to have a bigger chore getting it all to dial in.



looks good for coast, what does the drive side look like?

I dont think it looks as good but it doesn't make any noise.

 

[biminiLX]

All my gears have been silent until the first hard DR launch at strip. This extra braced 8.8 will only see bias ply launches and if it starts whining I'm going 9"
-J

 

[RedVenom48]

All my gears have been silent until the first hard DR launch at strip. This extra braced 8.8 will only see bias ply launches and if it starts whining I'm going 9"
-J

Per your rec, i added the Ford Racing G2 cover. That thing is BEEFY. Id rec anyone running a. 8.8 to get it if your going to be running at the track.

 

[nxhappy]

don't worry about it. run it till she blows.

 

[gimmie11s]

^^ +1

 

[biminiLX]

Per your rec, i added the Ford Racing G2 cover. That thing is BEEFY. Id rec anyone running a. 8.8 to get it if your going to be running at the track.

Good to hear man! I always like to hear guys building fast strip snakes, and good when we can help each other. What diameter rear wheel do you run? I've expanded my attempt to say my current 8.8 by not launching on DRs at the track, sticking to bias ply.
There are new 17-18" bias ply options for us, I'm going to do the bias 17" ET Street R if I can't fit the 16" Hoosier QTPs.
Just another hypothesis that the violent DR hop is contributing to our 8.8 intolerance to strip abuse, and the whine I can't stand!
Good luck, let us know.
-J

 

[69b302]

If the nut didnt work loose youll be fine. Just torque it down and go is what I would do.

+1, a solid sleeve should not compress further and change your bearing preload. You could measure your overall rear end preload/resistance, then torque to spec and see if it changes. If you do decide to replace the pinion bearing, I would also replace the races. They usually start quiet, and then go down hill after some abuse.

 

[shelbysnake11]

Well I also messed my rear gear install up somehow. My 8.8 has welded tubes, pinion brace, moser 31 spline axles, solid crush sleeve spacer, eaton true track, ford racing 4.10 gears, arp carrier studs, ford racing diff cover/ girdle. Installed it all today. I got what I thought was a good pattern.

On the drive side of the gears the pattern is great but the coast side is down on the inside of the gear.

After struggling with the gear pattern and pinion depth, (pulled carrier and pinion about 10 times changing shims) I decided to try this pattern. All is good on the drive side but on decel from 60mph down to 40 I get a very loud and noticeable whine.

Im not sure how a gear pattern can be so good on one side of the gear and not so good on the other. Could I have a possible gear manufacturing issue?

Anybody else have this problem?


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