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Back from Tellico with problems.....rear axle woes...

Safari Ary

NAXJA Forum User
Well, I finally made it home. I had to stop over in Chapel Hill at Motorman's house to swap axle shafts in the front end, re-install my front DS, pull the rear DS, and limp it home in FWD. Now here's my problem. When the rear DS is in, I get a sound that would make you think a helicopter was about to land on you, but it only occurs when the gas is applied. When I'm coasting it goes away. The DS appears to be fine, i.e. no visible play in the u-joints whatsoever. This is an RE/Spicer DS that I got with my hack 'n tap SYE. Anyone got any ideas? Andy Zuber(of the carolina rock shop) mentioned it might be a toasted pinion bearing. Any other ideas? Thanks


BTW, this is an 8.25 rear end with stock gears, tires are 33s
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My vote is for the pinion not being setup properly(bearings/crush sleeve).I had the same thing happen when I put in my gears!
Have you checked the driveshaft for any missing weight or any bends or dents. May be the shaft is not ballenced. If the pinion bearing is toasted, I know for a fact that Andy can put an 8.8 under it no problems and he even has some in stock.

Well, I'm pretty sure it's not a bad setup since the set has 55k miles on it with no problems as of yet(stock gears from the factory).

There are no blatant clean spots on the DS, and no blatant clumps of mud to throw it out of balance, so I think that's out.

I never did put shims in when I did the SYE, so I'm gonna change the axle end u-joint regardless 'cause it's prolly had a hard life, but I put the SYE in 18k miles ago. However I did install AALs the day before the trip, so that may be the problem, I'll check it out.

Thanks for the suggestions keep 'em comin.


P.S. If it does end up being a bad pinion bearing, I have a set of 4.56s, the install kit and an ARB locker to put in this axle, I just don't have the funds to have them installed right now. So I'm prayin it's not the gears.
Sorry about that"didnt catch the stock gears".I still think youll find the bearings to be the problem.Im even gonna guess its the "front".
I'm gonna go for a completely different guess. Since it's only happening when you're on the gas, it's possible that your spring packs have worn out enough to wrap and throw your joints out of phase. The recent addition of the aal is what tips it off to me. You were probably on the verge of vibes before and now that you've changed the composition of your pack the vibes have reared their uglyness.

Well, it's not the u-bolts, I got half a turn out of the back two nuts on the driver's side, but the others were really snug, and I doubt this was enough play to cause the noise.

Sean, the reason I originally ruled out driveline vibes is that the truck doesn't really vibe, I've had nasty vibes before, but this is mainly just a noise. I can "feel" the sound through my foot when I'm on the gas pedal, but that's about it. No seat of the pants feelings. I will admit though that my angles are way off. I'll get some shims and see if that does it. How do I measure the angles(assuming I need to purchase an angle finder) so that I can order the correct shims? Thanks

You don't need to measure angles with an SYE, the pinion should be directly in line with the d-shaft.
Yeah.but it sure helps in determining what shims you need.I do think One-Ton is on to something though since Ary stated it was the only thats changed!
OneTonXJ said:
You don't need to measure angles with an SYE, the pinion should be directly in line with the d-shaft.

How do you suggest I know which degree shims to buy then? I was assuming I should measure the difference in angles between the pinion and DS and divide by two and order that degree shim. Thanks

The multiplier is actually closer to 1.25-1.5 depending on which axle you run and your driveshaft length.
My set up is similar to yours,3+ " ,used a 6* shim to point the pinion at the TC.Also had longer spring center pins made to hold the axle in place.A 6* shim is about 5/8 " thick at the rear.
Well, I found the problem. I really didn't think it was the driveline, but rather the pinion bearing. So I put the rear end on jack stands and let it run and looked for where the noise was coming from(I know, not the safest way to do it, but nobody was around and I didn't get under the Jeep). Anyway, the first thing I noticed was that my T-case is movin around a LOT, and the DS at that end is vibrating too, so I stop the wheels, and grab the DS. Well, the DS moved, so I'm payin attention to the U-joints, when I realize that the entire SYE flange is moving. The output shaft, however, is not. So I pull the DS again and tighten up the bolt holding the SYE flange(got a 1/2 turn out of it) and it still wobbles. So it seems my RE hack 'n tap SYE is the culprit, I'm about to get on the horn to RE and see what they have to say. I'm just prayin my output shaft isn't f-ed.

I pulled the flange and called RJ Clayton of www.authorizedvehicle4x4.com the guy I bought the SYE from and also a good friend. He said this isn't the first one he's seen, and that RE *might* warranty it, it's a toss up. I called RE, they said I can order a new one, send in my old one, and if it's a warranty claim, they'll refund the purchase price. If it's not warrantied, then I just bought myself a new flange. My biggest problem right now is I don't have any f-in money.:mad: I made the mistake of blowing it all in preparation for my trip to Tellico and didn't budget for breakage.

BTW, there's nothing noticeably wrong with the splines on the flange or the shaft, but we all know it doesn't take much to create a problem.



It might just be the bearing in the output housing. It's a common part that is not too difficult to change out.

Andy, if it's the bearing in the output housing, should I be able to tell by grasping the output shaft and trying to wiggle it?? If so, it's not the problem, 'cause the output shaft is nice and tight in my hands. I can put my full body weight into my tugs and pushes and it doesn't budge. Thanks

OK, then the bearing is fine. Is the companion flange (the part that the CV bolts to) loose on the splines? Is the CV nice and tight? There should be a tight spot in the middle of it's angular travel that the CV sort of wants to rotate around.


P.S. Ready to buy that Land Cruiser yet? ;)
The companion flange is the part that's loose on the splines. The CV appears nice and tight, only played with the front one, but I don't see anything wrong with it.

Ary "the land cruiser's at the upholstery shop right now" '01XJ