I decided to take pictures as I go along. See
Some findings as I opened up the differential.
1. It is full of gear oil. (means my oil change 2 years ago was successful)
2. On the bottom there is some amount of of, like, 100 grit metal
dust, settled down.
3. There was one foreign object on the bottom, see
4. The gears and such, do not seem to have any unusual damage.
A friend of mine found that exact same piece while doing a lube change on his
Durango and he had to take it in for a rebuild under extended warranty. I'll
find out exactly what they had to replace and get back to you.
My Ram had a very similar looking piece fall out when the cover was
removed during what was supposed to be a normal 24K fluid change. Pretty
much everything inside the diff was trashed, gears, bearings, etc. They
didn't seem to be surprised about it. They had to have a carrier brought
down from Detroit, and they gave me a loaner until it was done.
How did they know that the diff was trashed? How can I find out if
mine is trashed? Did you see the pictures, does it suggest that it is
in a good shape, bad shape, or perhaps it cannot be easily determined?
Besides that little piece, I did not find any other large objects in
the diff, but plenty of metal dust.
They called me to the service desk and took me back and showed me the
parts. There was signs of damage on every part I looked at. It was
pretty easy to spot the damage on the ring and pinion, and there was
metal "dust" all over the place. They were rinsing out the rear housing
while I looked at the parts, and there was a lot of crud coming out the
bottom where the cover went on. About the only thing left that was
reused was the axles and a few other pieces. It never really showed any
signs, or made any odd noises until a few days before I took it in. It
made a "clunk" when I made a right turn, and backed out of the gas at
the same time. After it was all fixed, it was much quieter than it ever
That looks like a Chrysler 9.25" rear end. You have to find where that piece
of metal came from.
This rear uses side adjusters instead of shims, which makes it easy. To
remove the carrier you remove the two 3/8" locks, which will allow you to
loosen the side adjusters (round disk with holes), then unbolt the main
bearing caps and the carrier and ring gear will come out. Also, you will
first need to withdraw the axle shafts. Push in on the axles, then remove
the C-clips inside the spider gears, then pull the axles out.
threaded and slotted pieces , one on either side, under bolted caps . They
hold the bearings the differential unit rides in , and they are used to
adjust the clearance between the ring and pinion gears . That piece (if it's
the lock , but they both appear to be in place) is what keeps the adjuster
rings from rotating .
You also need to completely disassemble that diff and inspect every
piece - including removing the pinion shaft . That 100 grit metallic dust
was ground off of something in there , it ain't normal . It looks from your
pics that the ring gear is OK , so we can probably assume the pinion is too
. You might be a very lucky guy , having caught this before it totally
trashed your axle .
<< I ain't nuthin' but a shade tree mechanic , but *nobody* works on my cars
unless it's an emergency >>
be as smooth as mirrors. Any small nicks or dings will cause
considerable metal-metal contact and overheating, especially at highway
speed. The hypoid gears make a VERY sliding sort of "contact", and if
there are mars on the surface, that will cause rubbing of the metal.
They will eventually smooth off again, I suppose. if you do try to
continue using this differential, I would see about getting magnetic
drain plugs for it, or making them if you have to (not very hard).
Then, I would go out for a short drive, drain the diff and refill.
If you want, you could take the oil and run it through a fine filter
and reuse it. A large filter paper in a funnel left to drain overnight
should get the metal out. The full diff contents might take several
separate funnels to run through in one day, though, as that stuff is
awfully thick even without foreign matter.
Otherwise, I'd keep draining and refilling it at gradually longer
intervals until you don't see any metal on the magnets anymore.
Of course, you HAVE to find out what bolt that retainer flap was
SUPPOSED to hold in place, and re-do that section.
Oh, hell, I didn't even MENTION bearings. This kind of crud must be
even harder on the bearings than the gear teeth! I think the main
tapered roller bearings may SOUND fine right now, but they are going to
fail for sure after this abuse.
I would agree with all the above and you really need to take everything
apart and clean it up and look at everything. This is probably covered
under some sort of warranty, and I wouldn't want to go through the mess
and hassle of putting a rear together again. Not to mention the smell of
the lube. Last time, I got some of it in my hair, and even after washing
it several times, I could still smell it.
side adjuster keeper is broken off. The gears don't look bad but the backlash
should be checked and some prussen sp? blue used to verify the contact area.
You're going to need a special tool for setting the torque on the adjusters.
You have to do it with the axles removed. The tool is simple enough to make. A
nut welded on one end of 2' of 1/2" all thread and a hexhead pipe bushing welded
on the other end. The right size hexhead has to be selected to fit into the
adjuster. You might as well replace the wheel bearings and seals while you have
it apart. Don't forget to check the backlash every time you change the
adjusters and after you torque every thing down. Make up a jig to hold the dial
indicator that bolts to the case using one of the cover bolt holes.
After you clean everything out and check for damage, you re-install the ring
gear/carrier. You'll need a dial indicator with a magnetic base or some
fixture to hold the indicator against one of the teeth on the ring gear, and
rock the gear. Tighten the side adjusters until you get around .007"
backlash. I use a phillips screwdriver, placed in the adjustment hole of the
casting and pry against one of the holes in the side adjuster, tightening
Then replace your adjuster locks.
.007 is fine if you're setting up a new gear set.
If he's reusing the old gear set, he needs to measure backlash
-before- anything is disturbed or disassembled.
When he reassembles and sets backlash and bearing preload, he
needs to set the backlash to what he measured originally.
1. There is no bearing pre-load on the carrier bearings, only the pinion
bearing, and we aren't discussing the pinion here.
2. If Iggy takes the ring bear backlash now it may be an invalid reading
since the side adjusters have moved, throwing the ring gear out of
Techincally, the backlash value is engraved on the ring gear. But for
practical purposes anything from .006 to .008 should be fine.
There absolutely is - what do you think the function of the adjusters is?
They get tightened to somewhere around 80ft.lbs. (don't remember exactly).
That's putting pre-load on the carrier bearings.
All tapered roller bearings require pre-load.
(cross-post to RCM removed - this is a truck issue, not a metalworking
issue. No need to pollute other groups - something I wish others would
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