99 XJ hp30 gear install questions

*I have searched and googled quite a bit and have only found bits and pieces of good information. Going to be finishing up this install this week and just want to make sure I got it right. This is my first gear install. For reference, these are G2 gears in the 4.56 flavor and a new carrier.

OK, Got some questions/confirm my plans for those guys that have installed new gears in their later model high pinion dana 30. Here's where I'm at:

-Diff is empty
-new carrier is assembled
-have master install kit(that doesn't come with either oil slinger or baffle-bought separately).
-Have everything organized and ready to go.

I am currently at getting the new pinion set up to be put in to check pinion depth. I am not reusing the stock inner(next to head) oil slinger as I have read it is too thick (.060). I have a new Yukon slinger coming in at .033 and the baffle that I managed to not beat up taking it out comes in around .020. From what I've read around, the starting point that most people are looking for is .057(total) which includes the oil slinger, the baffle that is between the race and the housing, and the shim that you add to get to .057.

I have made set up bearings(and inner pinion race) for everything. I am assuming I should try the original shim stack size on the opposite(yoke) end under the outer bearing with a set up bearing to be able to check for backlash, and adjust the inner(head) shim size if needed. Once I get the backlash set, I check for pinion preload(or do i set this first?) and get that set. Then Its on to the carrier preload and I've read that adding .002-.003 usually does the trick(after initially checking backlash with just enough shim that there is no side-side movement of the carrier(snug fit). And I know the process for checking carrier preload.

And that should be it right? Or am I forgetting something?

TOM

Set pinion preload with only the pinion installed. I prefer to be on the tighter side of the spec. Did your opinion come with any reference marks for the depth ? It'd be a plus or minus some number. If it does, I would reuse your shims and slinger with whatever the gears reference. Sounds like you have a good idea what you're doing, take your time and be clean!

There is a marking of "169" or "691" on the pinion. Not much help there.

I set my pinion preload first. once I get that I measure the carrier shims and put the same size but new shim in for the carrier then make sure its a tight fit to get the carrier in. then I check backlash and start moving shims from one side to the other until I get the proper backlash and maybe a hair tighter than spec.

POLAR_JEEP_04 said:

I set my pinion preload first. once I get that I measure the carrier shims and put the same size but new shim in for the carrier then make sure its a tight fit to get the carrier in. then I check backlash and start moving shims from one side to the other until I get the proper backlash and maybe a hair tighter than spec.

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this is how i do them as well. just did my D30 on sunday.

After you set the pinion preload, if your PD was off(when checking backlash and pattern) you would just adjust both shim stacks on the pinion evenly to keep the preload amount?

moparmansfield said:

After you set the pinion preload, if your PD was off(when checking backlash and pattern) you would just adjust both shim stacks on the pinion evenly to keep the preload amount?

Click to expand...

Yes. Another way to do this, is to leave the that shim stack out until you are sure of your pinion depth. Just tighten up the yoke nut enough to take end play out the bearings. If you were worried about making it too tight then use your torque wrench to measuring the rolling torque to 20 or something like that...

You need to get the carrier backlash close enough so you can get a good pattern to check the pinion depth. Once you have the pinion depth established then you can go back to getting the exact backlash that you want.

Backlash will change as pinion depth changes, but there is no need to move carrier bearing shims each time. The differences will be small if you started out close. If you move the pinion a bunch, then you'd need to move shims.

Also, I caution the use of setup bearings. The bearings can have some slop in them causing final setup to change with the real bearings, possibly out of allowed range.

Also you want to make sure the bearings are seated. You can do this by whacking the carrier with a soft faced hammer or rotating the pinion back and forth rapidly a bunch of times.

md21722 said:

Yes. Another way to do this, is to leave the that shim stack out until you are sure of your pinion depth. Just tighten up the yoke nut enough to take end play out the bearings. If you were worried about making it too tight then use your torque wrench to measuring the rolling torque to 20 or something like that...

You need to get the carrier backlash close enough so you can get a good pattern to check the pinion depth. Once you have the pinion depth established then you can go back to getting the exact backlash that you want.

Backlash will change as pinion depth changes, but there is no need to move carrier bearing shims each time. The differences will be small if you started out close. If you move the pinion a bunch, then you'd need to move shims.

Also, I caution the use of setup bearings. The bearings can have some slop in them causing final setup to change with the real bearings, possibly out of allowed range.

Also you want to make sure the bearings are seated. You can do this by whacking the carrier with a soft faced hammer or rotating the pinion back and forth rapidly a bunch of times.

Click to expand...

Great info here. Thanks.

How do we like this pattern? BL at .006

Not an expert, but you want it closer to the center. I think that means you'll need more shim on the pinion. I've on;y done one rearend, and that was an 8.8"... so...

-P

I agree. Looks like you're within .004-.006. Don't be afraid to overshoot it and step back as well. The half moon and straight line at the top is the giveaway here. Check out the pictures in this thread http://www.naxja.org/forum/showthread.php?t=1121766&highlight=pinion There you can see too much, too little, and just about right.

Yup. Moved it in .005 and it ended up right on. Had to adjust the backlash a bit and is now at .006.