DIY - Differential and Ring & Pinion Swap

[kodyo]

Originally Posted by GT86drifter

@Dustin @kodyo where you able to measure the pinion depth spacer?

What do you mean measure? It's a shimming process that varies between every assembly. The pinion depth shims generally come in a pack with the gear set you purchased and it's more or less a guess and check by looking at the gear mesh.

[mrk1]

Pinion height is sometimes written on the end on the pinion by the manufacturer. Pretty handy. I have also built a few diffs now using MFactory gears the pinion height has been the same each time.

[GT86drifter]

finished my r/p swap few days ago

factory spacer was 2.01mm

[rx3]

Hey thanks to everybody who contributed to this thread.

What's not quite clear to me is how you guys set the pinion depth?

Did you basically keep on changing the pinion depth as well as the ring gear offset until backlash and the pattern on the gear teeth both were as they needed to be?
Or is it possible to first set the pinion depth and then move on to setting up the offset of the ring gear (backlash)?

Also, with what paint did you color the gear teeth?

[kodyo]

Originally Posted by rx3

Hey thanks to everybody who contributed to this thread.

What's not quite clear to me is how you guys set the pinion depth?

Did you basically keep on changing the pinion depth as well as the ring gear offset until backlash and the pattern on the gear teeth both were as they needed to be?
Or is it possible to first set the pinion depth and then move on to setting up the offset of the ring gear (backlash)?

Also, with what paint did you color the gear teeth?

The way I did it was basically:
1) Set pinion depth, assemble, check mesh, disassemble, add shim, repeat. Do this until you get a good pattern on the gear teeth.
2) Use original shims and measure backlash. Try to guestimate what backlash shims you need next. Note that you can measure the current ones and use those to find your next set. The total thickness of the two added together is always constant.

I didn't do backlash until the pinion was set because the shims for backlash are $16 a set and I didn't want to spend a ton of money on shims. So I tried to guess based on my measurements after pinion was set correctly.

I used blue gear mesh paint the second time after I ran out of the yellow that came with the gears. The yellow stuff was much easier to work with IMO.

[ChrisD]

If I just wanted to swap the diff and not do the ring & pinion, would it be as simple as just following this guide up to the point where you're pressing the new bearing in with a hammer and metal block? I'm hoping so, as the rest of it looks a bit of a nightmare with all the measurements and shims etc.

I've had the diff case mostly off the car (just the central drive shaft / prop shaft left connected to it) and had the axles out of the diff before so I'm fine with that part, but once we open the case up that's all new to me. Just want to be sure what I'm getting myself in for if I try replace the diff myself (looking at replacing it with a 1.5 way kaaz clutch type if that makes any difference to anything)

[kodyo]

Originally Posted by ChrisD

If I just wanted to swap the diff and not do the ring & pinion, would it be as simple as just following this guide up to the point where you're pressing the new bearing in with a hammer and metal block? I'm hoping so, as the rest of it looks a bit of a nightmare with all the measurements and shims etc.

I've had the diff case mostly off the car (just the central drive shaft / prop shaft left connected to it) and had the axles out of the diff before so I'm fine with that part, but once we open the case up that's all new to me. Just want to be sure what I'm getting myself in for if I try replace the diff myself (looking at replacing it with a 1.5 way kaaz clutch type if that makes any difference to anything)

If you're opening up the pumpkin and swapping any part for another part, you'll have to do at least some amount of reshimming I would imagine. If you want a lower FD and want to swap for the Lexus IS300 pumpkin, it's a simple swap. Not sure if that helps. If you don't want to do it, a shop could do it without any headache for you.

[ChrisD]

Originally Posted by kodyo

If you're opening up the pumpkin and swapping any part for another part, you'll have to do at least some amount of reshimming I would imagine. If you want a lower FD and want to swap for the Lexus IS300 pumpkin, it's a simple swap. Not sure if that helps. If you don't want to do it, a shop could do it without any headache for you.

Nah I want to stay with the same final drive, just want to swap the stock diff for a Kaaz 1.5 way clutch type LSD. I really want to do it myself rather than getting a shop to do it, so I guess I'll figure it out and update this thread with the answer once its done

[kodyo]

Originally Posted by ChrisD

Nah I want to stay with the same final drive, just want to swap the stock diff for a Kaaz 1.5 way clutch type LSD. I really want to do it myself rather than getting a shop to do it, so I guess I'll figure it out and update this thread with the answer once its done

I don't think it will be nearly as bad as a complete rebuild. You only have to remove the differential. If I were to do it, I would do the following.

1) Open stock diff and measure gear backlash on factory gears using a magnetic base and a dial indicator. I would also use the gear mesh paint and get a good set of pictures that show how the gear mesh currently looks. Measure the torque required to rotate the pinion gear. You will use this to ensure correct preload of diff bearings(I believe the factory service manual has values for worn bearings as well, but I'd focus more on matching what it's at now or around that value).

2) Next, remove the stock ring gear and differential bearings (be sure not to swap which bearing goes with which race). Obviously no reason to touch pinion gear at all.

3) Put stock ring gear and stock bearings onto new differential. Again, don't mix up the bearing races.

4) You can try to use OEM differential shims, but the preload may not be correct (new diff being a different width slightly). Anyways, try to use the OEM shims at first and check the backlash, gear mesh, and input torque. If the input torque matches, you know the thickness of the two shims added together is correct. If the torque is too low, you will need to add a thousandth of an inch (guessing here) to one of the shims (too high, remove a little at a time). If the backlash is lower than previously measured, you will need to space ring gear further from pinion. If the backlash is higher than previously measured, you will need to space ring gear closer to the pinion. When you are adjusting backlash, note that you need to subtract from one shim and add to the other. The total thickness of the two shims needs to be constant after the bearing preload (input torque) is correct. Gear mesh will just be a sanity check after that.

5) Replace axle seals on the pumpkin prior to reassembling into car. Remember to use a multipurpose grease where the axle touches the rubber.

Let me know if anything needs clarification.

[NoGoodNames]

[rx3]

I've meanwhile replaced the pinion and differential too. (I wanted an OS-Giken and it was out of stock for quite a while).
I got an old IS250 differential, the pinion ring gear kit from Weir Performance and that OS Giken differential.

Once I realized how hard it is to get that bearing off, I also ended up buying a press (it was about €100 - definitely worth it, even if you only need it for this project).

I wasted a lot of time setting the pinion depth.

I actually ended up doing it twice because I initially used the original bearings. I think this was a well meant hint, but unfortunately the old bearings didn't have the exact same size (they did have the same thickness, but the size of the rollers differed).

Also, while I did read that the pinion depth is written on the end of the pinion, I got thrown off by the units.
It said 2.44 on the pinion which I interpreted as 2.44 mm, since the original measured 1.98 mm and some people here mentioned 2.01 mm. So, I thought 2.44 mm sounds about right.
It turned out to be 5.50 mm with the old and 6.22 mm with the new bearings. I then realized that 2.44 must have meant 0.244 inches which is 6.20 mm. It took me countless iterations to get from 2.44 mm to 6.22 mm (which was written on the pinion all this time). I wasn't not sure whether I deserved a trophy or a hammer on the head.

The differential housing is actually kind of nice as it came with these cooling fins. (They must have sold a different version here).

[rx3]

At least I was lucky with the backlash, as it measured 0.2 mm (the specs I got from Weir said 0.008" to 0.010") and I fortunately could reuse the old shims.

[ka-t_240]

Anyone got any extra shims for backlash?

[ChrisD]

Finally got round to having a go at this today and the first issue I've come up against is after opening up the diff case and removing the two covers that go over the bearings on each side, I can't get the diff itself out of the case... it just won't budge. In the OP's guide he just says "with a bit of work it will come out" but me and a few friends have all tried pulling it and wiggling it as much as we can and it won't budge.

So then we thought maybe its just the fact that the pinion gear is still meshed with the ring gear and that's stopping it all from moving because we haven't undone the pinion shaft nut. But I don't see any mention of undoing that pinion nut before taking the diff out of the housing in the OP's guide, and I was kind of trying to avoid doing anything to the pinion because I'm only swapping the diff and not changing ring/pinion for final drive change. Plus the toyota service manual seems to suggest that pinion nut needs an insane amount of torque, something like 280 lbs-ft.

So yeah, can anyone clarify if you need to remove the pinion nut (or anything else other than the two bearing caps) before you can pull the diff itself out of the housing?