Just saw your question about the pinion, crush sleeve, etc. and I agree, setting that up correctly, and with the correct parts made me nervous too, so I left it in the diff.. I’m hopeful I won’t have to pull it since my preload test seems to indicate whoever rebuilt this eBay diff I got, did it correctly and the pinion looks pristine. I got some gear oil down into the pinion shaft and it turns much more smoothly, and is measuring about 20 inch pounds on my old, likely inaccurate beam torque wrench.

I think the real test is going to be when I test the gear mesh with colored grease, and the backlash. Fingers crossed it was all set up correctly, and will go back in the same. Quaife says their unit won’t screw up backlash as long as you don’t swap the lock rings. However, if the gear mesh pattern or backlash is off, it’s going to get painful. It’s the reason I bought an eBay diff, so I could take my time and account for problems without having my X5 on jacks for a month!

I think I saw somewhere the crush sleeve is available as one used on another bmw model that uses the same 188k medium diff. Different thicknesses lock/snap ring sets are available from some company in Australia, and maybe elsewhere. I measured my two and they are only a very, very small difference in size.

Crown Ring Install
 

Sorry for the stream of consciousness updates, but I figure if I don't do them as I chip away at this project, I wont do them at all.

To the eye the quaife is dimensionally the same as the OE. The crown ring is a very tight fit, and won't fit over the shiny silver part above the flange when I tried with the ring cold.
https://i.postimg.cc/jdGw9j6m/quaife.jpg

The install was straight forward and per the instructions, which called for heating the ring to 100c in boiling water. Since I don't have compressed air to blow the threads out and avoid hydraulic lock, I stuck the thing in the oven at 230 degrees for an hour or so (after my better half left the house for work). After this all it took to get it to seat was some very light tapping with a rubber mallet. I then gave the bolts an initial torque, hand holding the diff, just to make sure it was seated on the flange as it cooled.

The instructions call for red loctite (or 271 permatex), an initial torque to 100 NM follwed by an additional 30 degrees. There are two flat spots on the casting which work nicely for a vise to hold. 100NM was quick, then I marked the bolts, and the case at 30 degrees past the bolt mark (6 pointed bolt head makes it easy to estimate 30 deg. Plus, the red loctite should make up for any slight errors)
https://i.postimg.cc/L4QZtDJH/quaife-2.jpg

The final 30 degree torque was a pain and I'm happy I had my long wrench. I'm guessing a couple hundred FT LBs, if not more at the end of the day.

Finally assembly, with the quaife model number.
https://i.postimg.cc/Nfy2pXXR/quaife-3.jpg

My cheap Amazon magnetic dial guage showed up, but I'm at a standstill until my output bearings, diff bushings, and pinion nut locking thingamajig show up (ebay diff showed up without one installed), and I get back from work early next week.

Looks great! Keep the updates coming :)

Update is there is no update. Work intruded last week and this weekend, and I’m waiting on parts. My output bearings came in though and once installed this week I can assemble the diff and check the backlash and gear mesh. I also ordered some misc driveshaft parts like a new center bearing and a new CV joint. It will be easier to get off since the diff will be removed and at 160k, a refresh is likely due.

Meanwhile, before leaving for work last week I spotted a decent size cooling puddle under the aft part of the stiffener. Looks like it’s coming from the bellhousing unfortunately. Fingers crossed it’s a heater or rear manifold hose connection loose and not the valley.

Is it the transfer case leaking?

Do you happen to have part numbers or links to the bearings you ordered?

Xfer case is fine, it’s leaking coolant from behind the motor, down through the bellhousing. Only three things it can be, and from what i can see so far, not the easy one (rear coolant manifold and/or hoses). That leaves the valley pipes and or pan, which will suck, but will be infinitely easier than the rear coolant cover that bolts down on the back of the block above the crank seal. It’s under the bellhousing, so that’s cool.

Intake is 50% off this am and I’m hoping to see coolant from the pipes or valley. 10k on a new motor and it’s already leaking. I’ll post some pics later, but the right vanos has a small weep that has made a bit of a mess on the front of the head. Nice work BMW.

Regrading bearings, the FAG taper bearings are no longer made, but Quaife, and others I contacted said FAG makes a ball replacement that will work. See email below from a UK company:
——————
We have the HAG205 kit in stock Which has the F-587739 which is the new part number for : F-801298
Is this the kit you require ?

https://www.bearings-online.co.uk/it...epair-Set.html
——————
I didn’t go too far down that rabbit hole as I found taper bearings at DiffsOnline. Ping Dan Fitzgerald at Dan@diffsonline and ask about the bearings he just shipped to New Orleans for an X5 4.4 diff. He’s the owner I think and does a lot of bmw diff work it seems.

The bearings look identical, but are made in Japan. We’ll see how they work. I had them pressed on yesterday by a local steering shop, so the diff is ready to assemble. As soon as I see where the coolant is coming from on my ungrateful x5.

Valley leak
 

Intake is off...took me about 1+45, and thats after shooting the $hit with my neighbor for 20 mins. Not something that I want to be good at, unfortunately.

Happily, the leak appears to be from the large coolant pipe at the rear manifold. It will be a PITA, but nothing compared to "door 3": the rear coolant cover. I was a bit concerned about this because the motor is so new I figured it could be anything, not just the usual suspects.
https://i.postimg.cc/L5Gztmyr/valley_pan_job.jpg

Sure enough, a mirror shows coolant dripping from under the large pipe, and the valley full to the weep-holes.
https://i.postimg.cc/hvXLQX0L/valley_pan_leak.jpg
https://i.postimg.cc/xjZyDP0t/valley_pan_right.jpg

I cleaned up the valley mess and stuffed a rag under the pipe to see if I may also have a valley pan leak. That would be super unlucky, but it is a BMW and I'd rather do both jobs now than have to pull it apart again.

I noticed oil around several intake holes, and the small oil return line from the dinky plastic nipple on the breather valve was off. This was a huge pita to get attached while dropping the intake on, and clearly I didn't do a good job. I'm wondering if this would cause oil to be drawn into the intake. I'll pull the valve and look at it, and the intake. The car doesn't use very much oil at all however, so I'm a bit stumped about the oil under the intake gaskets.

I sprung for new pipes, o-rings and rear manifold gaskets. I think I'm going to pull the manifold and get the pipes out that way. I reused my old ones, and my old manifold on the new motor, and I'd like to check the manifold out. It didn't leak for close to 2 years however, so I suspect I just rolled or cracked an O-ring.

On a positive note, I took the Quaife diff down to the local steering shop and had the press the new output bearings on. Much easier than me banging on them with a hammer and a big socket. Its ready to assemble and test for backlash and gear mesh.
https://i.postimg.cc/L61HNmCN/Koyo-Bearing.jpg

Thanks buddy, got your PM.
Glad you found the leak and it's pretty simple.

The side bearings are ridiculously expensive. This kit is 310 euros, which is like $500 CAD.

This was the original bearing
https://www.bearings-online.co.uk/it...f-Bearing.html

This is the new version that you mentioned
https://www.123bearing.com/bearing-h...587739-tr1-fag

This is stupid expensive lol.

Found the kit on ebay as well.
https://www.ebay.ca/itm/143786832897...mis&media=COPY

These rear diffs are pretty much bulletproof. I will just grab a used diff for $70 locally and use the bearings from it.

Looking forward to see your experience with driving this thing once you put it back together!

It's just so weird why they don't list this LSD for E53 3.0 Auto. I emailed Quaifie.
https://mattlewisracing.co.uk/produc...lical-gear-lsd

E53 X5 3.0i manual rear diff; 4.4i auto rear diff; 4.6is auto rear diff

It seems to me the diff type is 188k, the same for manual and auto transmitting
https://i.ibb.co/tzfz0SQ/Screenshot-...001-Chrome.jpg

You're definitely blowing it out of the water with this upgrade. Just the LSD and bearing set is over $2500CAD, more than the price of most E53s these days.

I spend more money on my X5 than on my gf but still can't justify the price tag lol!

It looks like there's a cheaper alternative, I'll give it a shot.

https://racingdiffs.com/products/bmw...conversion-set

Nice, we can compare notes.

The bearings did hurt a bit. The Quaife though I justified to myself by recalling almost getting stuck in Iowa mud and ice in 20deg temps last year hunting birds.

My wife gives me lots of rope on my projects, and I x5 is likely cheaper than a full 68 Camaro, or Alfa, etc. build. I drive the wheels off of the X5 now too that it’s back to daily driver status, aside from when it’s broken down of course, and that keeps me from buying something silly like another M3 or a 911.

My seats, if they ever get finished by the upholstery shop will be amazing. Won’t be cheap I suspect, but well worth it on the long trips.