V2 Diff rebuild + Gear Ratio Swap (4.10)

[bigjae46]

Yeah, pinion pre-load and crush sleeve is the LAST step.

Set backlash and pattern and THEN change the pinion bearings, races and seal unless there is obvious damage.

I think the 3.85 is the cutoff to where you may need a different shim. The pinion head get smaller as the ratio gets shorter. Then there are the tolerances stamped on the pinion.

Sorry, I would have said something. It’s been awhile since I’ve done this. I do remember always having extra carrier bearings on hand because they can get banged up since you need them installed the first step.

Empty diff case
Carrier preload (need nee bearings/races on)
Install pinion (no seal or crush sleeve)
Set back lash / gear pattern
Disassemble and clean diff (careful with the carrier bearings)
Replace pinion races
Install pinion with crush sleeve and seal
Set preload
Install carrier

[Slideways]

So for the noobs, is the coast too inset?


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Not an expert, but the pattern appears to be slightly closer to the face.

https://www.crawlpedia.com/gear_tooth_pattern.htm

[fattycharged]

So for the noobs, is the coast too inset?


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[maupineda]

More “progress”. My expectation that the pinion depth was going to be ok was wrong, despite the pinion top face being equally tall on both, the center point relative to the ring and housing may be deviated and so my depth is a bit shallow. The contact is centered heel to toe, but to close to the face of the tooth. also the backlash was almos same as before, 0.06mm. So I guess RD is not entirely correct, and is still possible that the depth needs adjustment, and not the side shims.

Without tools I will need to do some trial and error and find shims that get me there, I found some original shims ranging from 3.755 to 3.835, so I will aim for the tallest and go from there. I feel I may need a bit more than that, but also some small moves go a long way.

So up for the 3rd round of pinion removal.

Pro-Tip, if you are doing this, DO NOT change your bearings until the very last, as the races are delicate and this thing is heavy, so by removing and installing the carrier from the housing, you risk damaging the races, I also on the first go tightened the pinion much and it did score the race, so my OCD forces me to replace it, so will be at least two sets of bearings.

Here an image from TIS I used to tighten the ring, is not same as ours, but it helps to follow the correct pattern





As you can see backlash was nice and tight with original shims





Now the deal breaker. First image is drive, the second one is coast.

[sapote]

1. man, you should go back and check. I documented the ring was drilled and tapped before opening, that is how I know it went to its home position. Also there is a photo above.

2. Did not I say CARRIER? Not sure why you are inferring anything related to the pinion.

1. I was referring to your new post's pics showing the locking ring installed but no pump.
2. My bad.

[maupineda]

1. I don't see the pump in the pics but assume you had it when tightening the ring; if no pump then I don't see how you know the locking ring is at its final position.
2. What side caps that affects the pinion bearing preload? The output flange bearings preload should not affect the pinion bearing preload.

1. man, you should go back and check. I documented the ring was drilled and tapped before opening, that is how I know it went to its home position. Also there is a photo above.

2. Did not I say CARRIER? Not sure why you are inferring anything related to the pinion.

[sapote]

1. so before closing the carrier I wanted to see if I could make the ring close to the original position, to my surprise it goes to the same place with and without clutches.
2.The carrier preload seems totally loose, so will need to adjust it and start the gear mesh setup from scratch

I hope it won’t be too difficult

Edit: false alarm, I just had to torque the side caps, it is 2nm of preload, which is about midway the spec.

1. I don't see the pump in the pics but assume you had it when tightening the ring; if no pump then I don't see how you know the locking ring is at its final position.
2. What side caps that affects the pinion bearing preload? The output flange bearings preload should not affect the pinion bearing preload.

[bigjae46]

This is the one. I bought the version with two cups (orange and black) the one with white adds another size option.

https://www.vevor.com/bearing-inner-...le202412&gQT=1

F my life...where was this 3 years ago? lol

Just bought one.

[maupineda]

More info on that puller!

This is the one. I bought the version with two cups (orange and black) the one with white adds another size option.

https://www.vevor.com/bearing-inner-race-tool-c_10331/vevor-carrier-pinion-bearing-puller-clamshell-bearing-puller-w-3-clamshells-p_010910863646?adp=gmc&srsltid=AfmBOopBbomOfyf47W0XA47J9-MiFlHlthWGnzUPBZ6FOHDrFtFYIhRkDRQ&gPromoCode=google202412&gQT=1

[bigjae46]

More info on that puller!

[maupineda]

The carrier preload seems totally loose, so will need to adjust it and start the gear mesh setup from scratch

I hope it won’t be too difficult

Edit: false alarm, I just had to torque the side caps, it is 2nm of preload, which is about midway the spec.

i also gave the pinion a tad more preload to match the side and it is 2nm also.

base on all this I should have little trouble setting the gear mesh.

[maupineda]

This is how I measured the pinion to confirm if I needed to change the depth shim, and by how much.

First I setup the pinion on a precision block, and align the micrometer so that I could have the exact same setup for both pinions, I started with the old one


I also rotated the pinion to verify the runout, it is incredible that the micrometer did not move at all as I spun the pinion.

Here is the original one



and here the new, same, no runout as I spun the pinion, they are cut exactly the same.



then it was all about getting the pinion into the carrier and adjust the preload





Edit: spent time in ISTA last night and reviewed the specs for e36 chassis, and found that the pinion preload should be 2.5nm or 250ncm. I will redo this as I fear I may have screwed up the process.

I also found the carrier preload values which are bearing brand dependent. Will add here.

K = kompact or small
M = medium
G = grob or large

[maupineda]

To close the carrier I use the same method I used to open it, get to as close as I could, the. Zip tie it and use a hammer to tap the tool and lock it in place.


the final torque was a bit lower than what I expected, but it is very similar to how it was before, this makes me think the unit was still ok, also the clutches looked fine!


I was able to close the unit to where it was. I also shimmed the side gear with the play, and it is much reduced now that the unit is closed. I used 2 0.1mm shims with RC40 harness for durability.

Edit: took a photo of the carrier closed to the original position with it set screw to lock it.

[maupineda]

Continuing with the rebuild I made progress this weekend. Basically finished the carrier assembly as well as replacing the bearings and races, and setup the pinion preload.

I also installed the 4.1 pinion and made sure I did not have to change the pinion depth shim, RD say is very unlikely that the pinion shim needs changing, and was pleasantly surprised that it is true, I guess it has to do with BMW tolerances on these parts.

so before closing the carrier I wanted to see if I could make the ring close to the original position, to my surprise it goes to the same place with and without clutches







moving on, I removed the old bearings, for this I got a bearing puller and it worked great, it really removes the bearings in a breeze.



I did not take a photo of the pump side bearing but you must remove that with the pump off the carrier as the tool does not fit otherwise.

[sapote]

I have been playing with the shimming for the short output shaft side gear, I started with a 0.1mm shim, and I reduced the backlash some, but by feel it did not seem to do much. Then I tried 4 shims and with 0.4, the locating shafts don’t go in

The short output flange backlash is not just reduced by its own shims, but also depends on the plays of the other side-gear, because the 4 spiders still free to rotate due to their backlash with the longer flange side-gear. Imagine if the longer flange side-gear is removed, then the short flange side-gear would have infinite backlash.