Cracked ring on diff, and noises, oh my!

[charles]

Hello;

 

Hoping for some insight on this one... I have a '94 XE with at least 310,000km. Just purchased, trying to sort out the few concerns I have.

 

I was hearing a ticking noise coming from the rear, sounded quite mild, almost like a twig in bicycle spokes. Never happened under acceleration, occurred just when coasting when the vehicle was slowing down under compression, or sometimes as the clutch engaged (but cut out again when the clutch fully engaged).

 

My friend and I jacked up the rear axle and replicated the noise. It sounded like it came from just forward of the rear final drive (that's what the rear differential is called, right? The big round boxy thingy in the back that the rear wheels connect to?).

 

A quick peek forward of the rear diff and voila! See attached pic for the cracked whatever the hell it is. Harder to see is that the 'holes' for the bolts have the outside missing, so the 'holes' are like crescent moons. Basically it looks like its barely holding on. The diff moved up and down depending on whether or not it was receiving power or not, not sure how much movement is normal? But this made sense with when the noise was happening... under power the diff is pushed one direction, when coasting the wheels push it another, plus flex offered by the crack, causing a part of the sensor to rub onto a spinning part?

 

 

https://www.dropbox.com/s/1z73jimwcf3uyjg/Cracked%20ring.jpg

 

(An aside, what's the best way to add photos to posts? probably not this ^)

 

Took a while, but I eventually found a diagram of a diff that had this part. I believe it is the ABS sensor unit? Anyway, driving to school today the sound was all of a sudden way louder, and is now pretty much constant. I hit a few bumps coming out of the driveway... maybe that made it worse? The crack looks wider now anyway...

 

So I'm wondering if I can replace just this part without having to mess with the diff? I think I must have either the C-200 rear final drive or the H233B (4 pinion type) according to this:

 

http://www.autozone.com/autozone/repairguides/Nissan-Pick-ups-and-Pathfinder-1989-1995/REAR-DRIVE-AXLE/Final-Drive/_/P-0900c1528018d4ea

 

Guessing I can't just smash it out, it's probably holding tension/space/etc. I'm hoping that because it is front of the oil seal, replacing will be simple? But it looks like I have to remove the drive pinion nut to get the companion flange off, so in order to get this abs thing off... does that necessitate a overhaul of the trans? Can I still drive the thing? What would happen if this ring totally came apart?

 

I thought about cleaning it up, throwing a jack under it to squeeze it together, then trying to weld it together, but A) I'd be using car batteries and jumper cables as a DC welder and apparently aluminum is a doozy to weld with proper equipment and C) who knows what that might do to nearby parts?

 

LORCO can't order it, so I guess I'm off to a wrecking yard? Anyone have rear diff parts lying around? Ideas on fabrication? High-density plastic as a temp?

[charles]

This is regarding a 2002 Extera... but could it be relevant?

 

http://www.clubxterra.org/forums/showthread.php?t=38953

 

Might I have a differential from another vehicle/year/model?

[SpecialWarr]

Don't bother trying to weld aluminum without the correct sheilding gas. It won't work as the elements in the aluminum will instantaneously combine with the nitrogen and oxygen in the air and create pores in the heated material. The pores are not themselves atached to each other.

 

Sent from my SGH-T999V using Tapatalk

 

 

[adamzan]

I dont think it holds anything, but I could be wrong. Mine has been messed up for a while now but doesn't make noise

[charles]

It certainly could be two issues... something making the noise, which made me look there, and then saw this visually repulsive cracked/smashed piece.

 

I'm tempted to rip it off to see if the noise goes away, because if the noise does dissapear, then I'm done trying to diagnose it! Downside is, no ABS... but it probably already doesn't work?

[charles]

Quick follow-up for anyone else who might stumble across this... I WD40'd the hell out of this ring, anticipating trying to take it off. The noise is now completely gone. Apparently the tiniest bit of rust on the exciter ring can cause quite a bit of noise, which I think is the ticking noise I was hearing. So a similar noise can mean worse things, worn gears, etc., in the diff, but it could just be a bit of rust on a 'whatever' part, so give this a go first!

 

[jgrote]

So wait, the rear ABS is controlled by a sensor on the driveshaft and not sensors at each wheel? What's the point in that? I think I'd just ditch ABS.

[Alkorahil]

So wait, the rear ABS is controlled by a sensor on the driveshaft and not sensors at each wheel? What's the point in that? I think I'd just ditch ABS.

That is correct, there is one sensor on the propeller shaft, not two on the wheels.