So...Long story short, converting my xj from 2wd to 4wd. Bought a used D30 from a 98? TJ. It is low pinion. So figured they were the same as far as internals go. Ordered a 4.56 regear kit and carrier from rusty's using motive gears. Thought this would be easy, but boy was i wrong. Im out of my depth on this, more because i have no idea what im doing, as this has gone from a straight forward swap to sheer chaos with wrong parts all over the place.

I ordered the gears probably about 6mo ago. Sat on the shelf while life got busy. Come to a couple weeks ago, i get the courage to tear apart the front diff. Take it slow and try to save everything for verification minus carrier bearings as i cut those off, before i bought a bearing puller the following day. Pull out the master rebuild kit. First thing i notice is its a shimmed style kit on the pinion for backlash and preload. Second I had a crush sleeve come off of the axle. Third thing i notice is i had no backlash shims on the pinion/bearing/race as far as i can tell. Nothing came out that i can remember beyond races, sliger, and baffle. fourth thing i notice, i ordered the wrong gears. Accidently ordered reverse cut vs standard cut as i must have got stuff mixed up. And fifth thing i recently discovered rear pinion bearings are different too. Sixth thing is theres an extra random seal that came in the kit and i have zero idea what its for.

So i measure the pinion carrier/bearings, carrier is all good. Measure the pinion, same length/bearing seats are same diameters/steps all are the same. look at the bearings, front bearing is good. But found out the rear bearing is a completely a completely different size than the old one. The old bearing OD is much smaller than the new bearing that came in the kit, when you throw it in the axle, it sits outside of where the old bearing is in the cavity ment for the pinion seal, and wont allow the seal to fit,

So to my questions.
1. I should be able to throw the backlash shims behind the front pinion bearing race and be good correct?
2. Do i have to go back to a crush sleeve for preload? Or could i stick with shims?
3. Could i just order a new rear bearing based off the part number on the old bearing for the pinion and then throw it all together and be good, or do i need to just order a whole new rebuild kit?

 

You might want to verify which parts you purchased and get the correct parts before going further.

No. All pinions are slightly different in terms of depth and the difference should be marked on the face of the pinion gear. Although Dana 30 pinions are notorious for not having proper markings due most of it's aftermarket gears being machined in India.
The shims behind the front pinion bearing are pinion depth shims. Nothing known as a backlash shim for the Dana 30 LP or HP. While pinion depth does effect backlash, carrier shims also affect backlash.
The thickness of the oil slinger also effects pinion depth.

You don't technically "have" to use a crush sleeve in the low pinion 30 but it is recommended and it's easier.

Are you sure that the rear pinion bearing doesn't press on? That bearing is an interference fit. It presses onto the pinion shaft as the nut is torqued down with the baffle and yoke in place. If it is truly the wrong bearing, call whoever you bought the kit from.

Consider making setup bearings and races.

I would get a crush sleeve. Then I like to put .030" ring gear side, .065" non ring gear side for carrier shims. .075"-.085" total pinion depth shim, that total includes what is usually a .060" slinger. (Pinions can be .010" +/- in depth) Then crush the pinion/yoke assembly to 20"#.

 

Set up bearings are a must on pinion and carrier. Your almost waisting your time if you dont make a set.

Get a hi pinion houseing i think thats what your parts pile is telling you.

I dont prefer the crush over shims.

youl get it.

To me it sounds like you need to watch 10 or so more you tube vids of different people doing gears. Dont go off just one guys way of doing it.
Ive never heard backlash shims. You get back lash as a final result of depth and carrier shims together. .008 is what your looking for backlash not more than .010 and .005 is getting tight.

But then you gota have gears contacting in a good pattern no matter the backlash you end up with

 

I appreciate the feedback. I figured out my issue. I somehow misread info and thought LP d30s were reverse cut vs being standard cut. So when I ordered the kit from rustys I got a d30 reverse cut and 8.25 gears and rebuild kit. And based off the difference of pictures (however reliable those are) the HP d30 does not use a crush sleeve whereas the LP d30 does. So I've had to order standard cut gears and a new standard cut d30 master rebuild kit. As much as I'd like to have a HP d30, they're damn near impossible to find here as well as down right over priced. But on the flipside, if I ever come across one I have the gears and master rebuild kit ready and on the shelf to build it up.

As for backlash shims. Yall are correct, i should have said pinion depth shims, which is what i ment. As a bona-fide idiot, using correct terms is not my strong suit when I'm not well versed haha. Also doesn't help I was a few beers deep in a 120deg garage

And set up bearings are gonna be made. I bought an extra set of carrier bearings to hone out, pinion bearings are alot more expensive, so I was only able to save the tail pinion bearing (closest to the yoke), which sucks. So will need to find

 

A front axle out of a 99 or older XJ is hard to find?

 

Nearly impossible out my way.

 

Yup im in the PHX area. If they do pop up people want $300-600 for it. For comparison any type of D44 is at least 1k, and any 1ton axle is at least $1200. Which is sad. There arent too many junk yards around my area either. If an XJ does pop in, its raped and pilaged within a week.