First Rear Axle Rebuild
10-26-2010, 07:28 PM
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First Rear Axle Rebuild Well, finally got all the parts to rebuild my rear axle about 2 weeks ago, and completed the install on Sunday. New bearings/seals, Eaton 400# Diff, Moser Axles, 3.73 gears, 1/2x20 screw in studs, Ratech Solid Spacer. I took my time with everything and triple checked pinion bearing preload, etc multiple times.
Took it for a few short test drives and let it cool off each time. Heard a slight whine from it the next day, only when accelerating. I used a .036 pinion shim as advised from a reputable builder (builds high HP Impalas) The pattern looked good to me when I looked at it, but I'd like some other opinions, and also any clues to what could cause the whining. I'm out of town right now (TAD to Melbourne, FL for 4 days) and plan on checking things out again and checking the pattern when I get back to VA.
Took it for a few short test drives and let it cool off each time. Heard a slight whine from it the next day, only when accelerating. I used a .036 pinion shim as advised from a reputable builder (builds high HP Impalas) The pattern looked good to me when I looked at it, but I'd like some other opinions, and also any clues to what could cause the whining. I'm out of town right now (TAD to Melbourne, FL for 4 days) and plan on checking things out again and checking the pattern when I get back to VA.
10-26-2010, 10:27 PM
#3
There's never a "set" number for shims no matter if you're working on identical cars or components. Even from factory identical vehicles could vary several thousands on the pinion shims.
For YOUR specific rearend, you can START with the original shim, but there's no guaranty that's going to be your final amount, especially with aftermarket components.
Hopefully someone with experience can give you advice with the pattern. It's a little hard to discern, i'm wondering if you applied a slight load while tracking it.
You might also list pinion preload, carrier preload, back lash, and even brand of gears.
For YOUR specific rearend, you can START with the original shim, but there's no guaranty that's going to be your final amount, especially with aftermarket components.
Hopefully someone with experience can give you advice with the pattern. It's a little hard to discern, i'm wondering if you applied a slight load while tracking it.
You might also list pinion preload, carrier preload, back lash, and even brand of gears.
10-27-2010, 06:35 AM
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Thanks guys. The original shim I pulled off was .036 as he said, so I just measured it out with new shims and put it in.
Pinion bearing preload-28in/lb
backlash-~.010 (if i remember correctly)
Gear brand - OEM GM 3.73s w/ ABS Reluctor
Pinion bearing preload-28in/lb
backlash-~.010 (if i remember correctly)
Gear brand - OEM GM 3.73s w/ ABS Reluctor
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10-27-2010, 12:27 PM
#14
also, i think the only gears i know that call for a .010 backlash are richmond. Don't most others call for something between .005-.009?
Someone please correct me if i'm wrong.
And there is a difference between Motive GM gears and Genuine GM gears. But not to worry cuz most would agree Motive is better quality, and Genuine GM is ridiculously expensive.
Someone please correct me if i'm wrong.
And there is a difference between Motive GM gears and Genuine GM gears. But not to worry cuz most would agree Motive is better quality, and Genuine GM is ridiculously expensive.
10-27-2010, 12:30 PM
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Pattern is deep. I would also question the authinticity of them being OEM, that picture is not even the proper ring and pinion for this application.
10-27-2010, 02:27 PM
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The picture in the link provided of the gear set is reverse rotation LOL. Its a front ring and pinion. Plus the cut on the gears, all the new GM gears are 2 step gears, more curve to the teeth. The one mounted with the pattern is clearly a 5 step gear, traditionally used in aftermarket gears.
