1989 Cherokee

DirtyChemist

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Oh I’ve been all over that website recently. Also Filthy Motorsports on how to tear them apart, Billabista’s bibles and some YouTube. I SERIOUSLY don’t know how people made such great resources for information that have lasted so long. There is so much information out there I go from ‘I can do this if I take my time’ to ‘HOLY SHIT NO WAY!’
 

DirtyChemist

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Sterling 10.25 backlash measured 0.013-14. I could get it to move more but I assumed backlash is the free plant and not a measurement of how far you can move things.

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DirtyChemist

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Sterling 10.25 Yukon Grizzly install was interesting. You would THINK replacing the carrier and bearings would be as simple as ‘installation is the opposite of removal’ and it’s somehow not.
First install was so tight I broke a factory shim.
Second was so tight I scuffed up some of the thicker shims and then couldn’t rotate it. Assuming it was too much carrier preload I just kept removing shins then replaced the other factory shin with aftermarket ones. There is probably too much carrier bearing preload when you consider measuring backlash on the yoke because you can’t rotate the carrier easily.



0.006-8” backlash measured the best I could. Before removal it was about 0.012-13”.
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Carrier removed. No desire to replace the pinion bearings because the inner one is MASSIVE (close to 4” diameter) and I’m not changing gears.
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Nothing but MEAT. Gotta keep that meat juice smell off my locker too. Freezing the locker to shrink it for gear install seemed to go very fast. I put it in there for max 1 hour and the ring gear seated nicely as long as I did my part to line up holes. I kept the tone ring because maybe one day I use it for a speedometer.

For fun I tried to weigh the factory one complete. It’s more than the 55 pounds my scale can hold.
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Installed...with carrier bearing preload so tight I’ve broken a shim and will take a break to wonder how effed I am.
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Ring gear pattern before disassembly. 0.012” backlash.
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I’ll post pictures of the NOW gear pattern later. I ‘finished’ around 11pm Monday night. Due to COVID 19 my commute isn’t very long. The pattern, to me, with 0.006” backlash is acceptable. The pattern is closer to the toe on the drive side compared to the photos above. I think it looks comparable on the coast side.
 

DirtyChemist

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Actually I might need to decrease backlash a bit and see how that goes. It should move the pattern away from the toe and more towards the middle. In a perfect world it would set everything perfectly removing just one shim. The headache is Yukon says 0.007 shim changes backlash 0.010 which puts me out of spec. No way to know without getting in there and doing it again.
 

DirtyChemist

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Current pattern


Drive (Convex) side.
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Coast (concave) side.
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Yukon’s manual (no, these are NOT Yukon gears) says ‘concentrate only on the pattern created on the coast side of the ring gear teeth’ for used gears. Based on that I will probably pull this, move a shim to the passenger side, check backlash and re-pattern.

Mostly because:
Moving the ring gear away from the pinion (increased backlash) SHOULD move this pattern up towards the heel.
 

Shinobi

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Nice job man ! ya looks like your coast side could use just a skosh more backlash or pull the pinion out and mess with the shims.
 

DirtyChemist

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I put it closer to the backlash I measured initially. No sense NOT doing that since the pinion never changed. I considered replacing the pinion bearings and opted not to for simplicity. I have the bearings for later.


Ended up with 0.012” backlash. Driver side shim is 0.262 (factory was 0.279). Passenger side shim is 0.270 (factory was 0.285) and measuring backlash is much easier with less carrier bearing preload. I ended up removing 0.002” overall between the 0.006” backlash measurement and 0.012”.

Now to man up and do the hard one. The Ford 10.25 seems like an intermediate level gear setup. 14 bolt seems easiest and the Dana 60 is going to suck because of removing the bearings to place shims. Anyone want to lend me their $270 amazing bearing puller to make it easier?
 

DirtyChemist

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Because photos


Current drive side. I went HEAVY with the paint.
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Current drive side a few teeth away from the one above.
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Factory/stock drive side.
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Factory drive side.
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Current Coast side.

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Factory/stock coast side.
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Factory/stock coast side.
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I say factory/coast because the internet says this comes with 4.10s and the gears are marked Ford. I have no reason to believe it was ever re-geared BUT anything is possible.
 

DirtyChemist

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Crush sleeves suck. No one told me I’d need a 3/4” drive to get enough torque to crush it. God DAMN hose things are tough summmabitches. The Milwaukee fuel impact couldn’t even crush it with all the ugga duggas. Feels tight. Dial wrench says about 10 one way and about 4-6 the other. I’m not sure how I’d get it to 20+ without a yoke tool. Guess I should have replaced my yoke BEFORE sealing everything up.

OH WEEELLLLLL.
 

DirtyChemist

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Replace tracbar bushingS. Death wobble still exists. It’s probably ball joints because when Les Schwab aligned it they told me I had to have like $500 in adjustable ball joints for them to get it into spec. Probably should have gone somewhere familiar with aftermarket four link suspension adjusting.


Picked up a birthday gift.

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DirtyChemist

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Death wobble apparently solved. Tires out of balance. 2 ounces in one and 2.75 in another up front. Rears needed an ounce. $10/tire at Big O.

Wobble free at 55 mph
Yes I was scared to try going this fast.
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