Author Topic: 8 Inch diff Q's (Read 2369 times)

Duffil · « **on:** Jun 29, 2006, 08:02:02 PM »

I just pulled apart the front axle from my wreck. When I pulled the third out, I found this

The only time I've seen marks like that on a carrier was in some 4wd mag where the guy had his pinion bearings crap out. But the pinion looks fine, spider and side gears look fine, the backlash seems OK(I didn't check it with an indicator), wear pattern looks OK, pinion doesn't have in/out play. So, is this thing OK to run? or should I just throw bearings in it and get it setup while I have it out.

jimbo74 · « **Reply #1 on:** Jun 29, 2006, 08:06:17 PM »

do you know the history on that third? it looks like that could be old damage

79coyotefrg · « **Reply #2 on:** Jun 29, 2006, 08:06:26 PM »

looks like the outer pinion bearing left town or at one time the pinion nut was very loose

Duffil · « **Reply #3 on:** Jun 29, 2006, 08:09:12 PM »

PO installed rear, then the front(this one) a few thousand later, all road miles and no 4wd. As far as I know, I am the only one to put the gears to decent use, other than "ooh, it's dirt!!! lets use 4x4!!"

There were a significant amount of shavings the first (only) time I serviced the axle, but I think it was never done after the gears were installed.

79coyotefrg · « **Reply #4 on:** Jun 29, 2006, 08:09:23 PM »

yea those are rebuilt markings, it probably ate the pinion at one time, if your pinion is tight your fine

Duffil · « **Reply #5 on:** Jun 29, 2006, 08:10:26 PM »

Glen, that's what I thought, but I shook the crap out of it and it wouldn't budge.(I mean in/out) If the bearing was toast, it would shake like hell, no?

Duffil · « **Reply #6 on:** Jun 29, 2006, 08:11:19 PM »

Quote from: 79Coyotefrg on Jun 29, 2006, 08:09:23 PM

yea those are rebuilt markings, it probably ate the pinion at one time, if your pinion is tight your fine

Whaddya mean, rebuilt markings?

DTB · « **Reply #7 on:** Jun 29, 2006, 08:16:16 PM »

Quote from: Duffil on Jun 29, 2006, 08:11:19 PM

Whaddya mean, rebuilt markings?

I think he means on the ring gear

79coyotefrg · « **Reply #8 on:** Jun 29, 2006, 08:17:47 PM »

Quote from: Duffil on Jun 29, 2006, 08:11:19 PM

Whaddya mean, rebuilt markings?

those scribed markings are from being rebuilt

Duffil · « **Reply #9 on:** Jun 29, 2006, 08:19:16 PM »

Gotcha

jimbo74 · « **Reply #10 on:** Jun 29, 2006, 08:21:00 PM »

the markings on those gears are what people use to set the gears..... he means rebuilt marklings as in someone serviced that third....
if the po did it himself than he probably had a problem with it befroe, i dont know that the bearings would shake like crazy if they were bad, however if all your stuff is tight and the pattern is good, there is most likely nothing to worry about running it....

79coyotefrg · « **Reply #11 on:** Jun 29, 2006, 08:21:38 PM »

if the pinion and bearings are tight your good to go,

Duffil · « **Reply #12 on:** Jun 29, 2006, 08:22:47 PM »

He didn't do it himself, I know the shop that did.
Thanks Glen!!
Cool, looks like I'm good to go!!

79coyotefrg · « **Reply #13 on:** Jun 29, 2006, 08:24:59 PM »

brake a tooth pick and lay the third on its side so you can put the toothpic in a groove on the ring gear, rotate the pinion around, it should just mark the tooth pick

jimbo74 · « **Reply #14 on:** Jun 29, 2006, 08:31:01 PM »

Quote from: Duffil on Jun 29, 2006, 08:22:47 PM

He didn't do it himself, I know the shop that did.

thats fine too, anyone hwo sets up gears usually makes some kind of mark on it....

Duffil · « **Reply #15 on:** Jun 29, 2006, 08:35:47 PM »

I'm not going to pick at nits...I wasn't being a richard, just clarifying.

NATO4X4 · « **Reply #16 on:** Jul 01, 2006, 07:37:41 AM »

I had a carrier with the same marks. It was due to a front driveshaft being too long, I think. Originally I had 1-1/2" of compression left on the splines but my front springs settled after a hard wheeling trip and my shaft started bottoming out. I checked backlash and my pinion seemed solid. I took an inch out of the shaft and I'm pretty sure I'm ok now. It seems strange that the pinion would push in that much but it was the only thing I could come up with. Is there a chance that the shaft on that diff was too long?

79coyotefrg · « **Reply #17 on:** Jul 01, 2006, 08:29:49 AM »

Quote from: NATO4X4 on Jul 01, 2006, 07:37:41 AM

I had a carrier with the same marks. It was due to a front driveshaft being too long, I think. Originally I had 1-1/2" of compression left on the splines but my front springs settled after a hard wheeling trip and my shaft started bottoming out. I checked backlash and my pinion seemed solid. I took an inch out of the shaft and I'm pretty sure I'm ok now. It seems strange that the pinion would push in that much but it was the only thing I could come up with. Is there a chance that the shaft on that diff was too long?

this happens with crush sleeves, thats why everyone goes to solid spacers

NATO4X4 · « **Reply #18 on:** Jul 01, 2006, 06:05:48 PM »

Quote from: 79Coyotefrg on Jul 01, 2006, 08:29:49 AM

this happens with crush sleeves, thats why everyone goes to solid spacers

When this happens, does the crush sleeve crush get over crushed resulting in improper pinion preload? How critical is it to rebuild the third after this has happened? I have not loosened the pinion nut since I noticed the marks, seems like the preload would be ok. I have not checked it.

79coyotefrg · « **Reply #19 on:** Jul 01, 2006, 06:52:52 PM »

well when the crush sleeve gets crushed it pulls the pinion gear into the carrier, you can tighten the nut to get home, but if the outer pinion bearing fails you in bad shape

Duffil [OP]

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