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Bad 9.25" rear end pinion bearing (LSD upgrade opportunity?)

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Old 10-20-2014, 08:06 PM
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Default Bad 9.25" rear end pinion bearing (LSD upgrade opportunity?)

After nearly 140,000 mil and many tens of thousands of miles abusing my 2004 3.55 RWD pickup with a somewhat heavier than Ram 1500-rated slide-in camper (helper springs necessary), my pinion bearing is done.

I've not yet torn it down but was considering adding a Yukon Dura Grip carrier assembly (YDGC9.25-31-1 ) to my order of Yukon master and axle bearing and seal kits. The Dura Grip carrier appears to be a drop-in upgrade for my open carrier.

Is there a downside (other than the $460)? I figure an LSD would reduce the time I spend harvesting traction materials from the roadside and adjacent forest lands when I become stuck in snowy weather.

I've worked on plenty of engines and transmissions, but this will be my first rear end job. Even though everyone seems to discourage amateurs from doing rear end work, I've reviewed the Yukon instructions and watched a few YouTube videos. I have a small hobby machine shop, floor press, welding gear, etc. and the setup just doesn't look at all bad to me. I can make my own tools, when necessary.

Feedback and advice would be much appreciated.

-Cal
 
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Old 10-20-2014, 09:01 PM
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Get a set of 4.56 gears also!!!! Best thing I ever did. I will never regret it! And u won't neither!
 
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Old 10-21-2014, 01:44 AM
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That's a pretty good idea and well worth the $300 upgrade, I'm sure!

I pulled the cover and drained the oil but ran out of time for any disassembly tonight. Everything looked and sounded good (except for the pinon bearing) and I found no signs of any additional damage yet. There was only a small amount of metal in the oil--all very fine and no big chunks.
 

Last edited by calinb; 10-21-2014 at 01:49 AM.
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Old 10-24-2014, 12:26 PM
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I had an Detroit Tru Trac installed when mine went out. It's been bullet proof ever since.
 
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Old 10-25-2014, 03:29 PM
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I got my rear end apart. Sure enough--the front pinion bearing was the culprit and the left axle bearing was just starting to go too (maybe from the fine metal particles in the oil...who knows?).

After studying the Yukon manual and videos and also the Chrysler factory and other YouTube videos, I'm concerned that installing new gears will likely make my job tougher, because the new gears will likely require a spacer thickness that's significantly different from my original gears.

On the other hand, if I just re-install the old gears and install new pinion bearing spacers that match the thickness of the old spacer, my pinion spacing will probably be close to correct and, hopefully, I won't need to pull the parts and redo the spacers too many times. I'm not too keen on the fact the the only way to adjust the spacers is to drive the pinion back out of the housing, which imparts axial loads on the new front pinion bearing. In fact, if I have to pound the new pinion bearing back out to re-space/shim the pinion, I'll probably buy another new front pinion bearing for my final fitting. After all, the front bearing was the weak bearing that failed in the first place and why take chances on a damaged bearing, given how much time and money I'm putting into the project anyway?

The Chrysler video shows a nice looking (expensive, no doubt) tool to get the pinion spacing close. Essentially, it's a dummy pinion and carrier with machined surfaces to trial fit and slide spacer packs in and out. In theory, it would allow a mechanic to determine the proper spacing for their rear end housing. As the video explains, an additional adjustment to the spacer pack thickness is then made, based on the factory markings on the gears. Pretty slick and I'm sure it's a setup that few shops have!
 

Last edited by calinb; 10-26-2014 at 12:45 AM.
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Old 10-26-2014, 02:09 PM
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I just learned that I need a "setup bearing" to do this job right. It is a front pinion bearing with an oversize inner race so you don't have to press it on and pound it off each you adjust shims during setup. At nearly $100, it costs more than the normal dual pinion bearing kit!
 
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Old 10-26-2014, 09:09 PM
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It just dawned on me that I should be able to make my own setup bearing by grinding the ID and then polishing it smooth. If I can get the bare Timken bearing only, it would be really cheap!
 

Last edited by calinb; 11-09-2014 at 12:59 PM.



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