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I wonder: my research says I should be able to swap the ring gear from the M96 to the M85 and have an M98: 43:11, 3.909...
Are you suggesting that you can change ratios by changing only a ring gear?

Regarding setting up a rear end:

Definitely don't sandblast the case with the pinion still installed. There is a 0% chance you'll keep the grit out of the pinion bearing, and a 0% chance you'll be able to clean it all out once it's in there.

Rear ends aren't that difficult, but they're tedious - especially when setting up a used set of gears from a different housing. The gears absolutely break into one another and unless the original setup is duplicated identically - it'll be noisy. Duplicating that original setup is nearly impossible. That said, so long as the new setup is all in-spec, it'll still live a long happy life - even if it whines a bit.

You'll need some new crush sleeves, and to buy/make a special lever tool that bolts onto the pinion companion flange (that the driveshaft U joint flange bolts to). This way, you can keep the pinion from spinning when you put the 400+ foot pounds of torque onto the pinion nut while you crush the sleeve and preload the pinion bearings.

If you are replacing your pinion bearings - it's really helpful to hone out your old one so it is a slip-fit onto the pinion. This way, you can easily slide it on/off to try out different pinion shims rather than needing to use a bearing puller and press each time. Also, it's helpful to machine a "solid" crush sleeve for checking setups so you don't have to crush/waste (and put 400 ftlb onto) a one-time use crush sleeve each time.
 

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Discussion Starter · #22 · (Edited)
Are you suggesting that you can change ratios by changing only a ring gear?
It's moot now as I intend to keep the pinions and crowns together, but yes: I was more asking than suggesting: are the hypoid cut pinions of the same tooth count (11) cut the same to operate with crown wheels of different tooth counts (43 vs 41). I notice they're stamped with their ratios and have slightly different finishing machining/manufacturering (visible in the linked album), and so I'll keep them mated.

You'll need some new crush sleeves, and to buy/make a special lever tool that bolts onto the pinion companion flange (that the driveshaft U joint flange bolts to). This way, you can keep the pinion from spinning when you put the 400+ foot pounds of torque onto the pinion nut while you crush the sleeve and preload the pinion bearings.
Dead bolt Gas Auto part Wood Circle

If you are replacing your pinion bearings - it's really helpful to hone out your old one so it is a slip-fit onto the pinion. This way, you can easily slide it on/off to try out different pinion shims rather than needing to use a bearing puller and press each time. Also, it's helpful to machine a "solid" crush sleeve for checking setups so you don't have to crush/waste (and put 400 ftlb onto) a one-time use crush sleeve each time.
The Hagerty video referenced shows this technique; very smart. I don't have a spare bearing at the moment so I'm hoping that as I'll keep the pinion with the original housing and since the carrier shims are [hopefully] identical between the two, that I won't have to mess with the pinion shimming assuming I can get the preloads correct with appropriate torquing. Otherwise, I'll just order new bearings and do this trick.

---

In both cases, the pinion gear face is 1.956" from the carrier centerline. :D
 

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In both cases, the pinion gear face is 1.956" from the carrier centerline.
Last year, I bought a FARO arm portable CMM for work. Used it to help my buddy set up some 3.90:1 Motive gears in his GM 14 bolt...worked awesome and allowed us to sweep in the carrier bearing bores, and set the pinion depth to within 0.0005" of perfect. Really made the whole setup a breeze.
 

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Last year, I bought a FARO arm portable CMM for work. Used it to help my buddy set up some 3.90:1 Motive gears in his GM 14 bolt...worked awesome and allowed us to sweep in the carrier bearing bores, and set the pinion depth to within 0.0005" of perfect. Really made the whole setup a breeze.
Thats very generous of your work to buy a $$$ piece of equipment for your homers! :LOL:

We have been toying with buying one of those for years at my work, hasn't been a viable option so far.
 

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Discussion Starter · #25 ·
Gesture Engineering Tool Electric blue Recreation

Holy crap, bring that puppy over here! That's one hell of a piece of fine engineering if it can achieve 0.0005" in that mechanism. What kind of work do you do, automotive mostly?
Wood Auto part Metal Engineering Machine
Saw Hand tool Tool Metalworking hand tool Eyewear

I must've been drunk last night because while the two right/passenger shims measure the same:
  • ~0.1088"; 2.76 mm (0.1087"), P/N 90201-52007 (mark '07')
... the left/driver side are different:
  • M85 LSD: ~0.1117"; 2.84 mm (0.1118"), P/N 90564-46022 (mark '40')
  • M96 open: ~0.1134"; 2.88 mm (0.1134"), P/N 90201-52011 (mark '11')
I don't see any markings on the shims.
Automotive tire Automotive lighting Motor vehicle Gas Rim

The service manual says to pull the bearing from the installed pinion, but I haven't a puller that can fit in the tight space. Can I just press the pinion out of the case, separating the bearing in the process? Basically the same procedure, right?
Bicycle part Automotive tire Gear Wood Rim
 

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Holy crap, bring that puppy over here! That's one hell of a piece of fine engineering if it can achieve 0.0005" in that mechanism. What kind of work do you do, automotive mostly?
Where you at??

It's a badass piece of work. I used them a lot back in 2008-2011, but they've gotten even better. I totally understand the theory of operation but it still amazes me that it actually works in real life. I have a set of 000 grade gage blocks, as well as an 18'' Cadillac gage, and the FARO will report a height off the granite within 0.0002" I gave ~$40k for it, and I didn't buy the laser option.

I design and manufacture custom force sensors for myriad applications, and have gotten into consultation and manufacturing a lot of odds and ends to support the space/aerospace industry - which is a big thing in my town. The automotive stuff was a prior career for me, but now just a hobby.
 

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Discussion Starter · #27 · (Edited)
Where you at??
Everyone keeps asking that: I'm in the midwest. That aero gig sounds like a sweet deal, kind of jealous. I wonder if you're near Wichita, I hear there's a lot of aero fab a-happening there.

Also, here's a professionally edited version of the Hagerty DIY video, in case anyone wants to save some time:

;)

And no offense to this guy, it's cool of them to make an instructional video, but what happens at 7:50 almost made me spill my coffee:
 

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Discussion Starter · #28 ·
You'll need some new crush sleeves, and to buy/make a special lever tool that bolts onto the pinion companion flange (that the driveshaft U joint flange bolts to). This way, you can keep the pinion from spinning when you put the 400+ foot pounds of torque onto the pinion nut while you crush the sleeve and preload the pinion bearings.

If you are replacing your pinion bearings - it's really helpful to hone out your old one so it is a slip-fit onto the pinion. This way, you can easily slide it on/off to try out different pinion shims rather than needing to use a bearing puller and press each time. Also, it's helpful to machine a "solid" crush sleeve for checking setups so you don't have to crush/waste (and put 400 ftlb onto) a one-time use crush sleeve each time.
The Toyota differentials don't have a crush sleeve, but instead a "spacer." The service manual suggests to set the preload without the spacer and seal installed, so no concern about that here; see "8.b HINT":
The service manual says to pull the bearing from the installed pinion, but I haven't a puller that can fit in the tight space. Can I just press the pinion out of the case, separating the bearing in the process? Basically the same procedure, right?
I just pressed these out with the press, did not pull the bearings out the input port. Keeping the nut installed retains the pinion from falling out of the case while pressing. I don't anticipate any concerns from this technique.
 

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Discussion Starter · #29 ·
The Toyota differentials don't have a crush sleeve, but instead a "spacer." The service manual suggests to set the preload without the spacer and seal installed, so no concern about that here; see "8.b HINT":
I stand corrected: the pinion spacer is indeed a crush sleeve; setting the preload it seems to have crushed at least 0.003", measuring the backlash with the same shims. Also, the nut seems to be threaded the same amount, if that helps someone.

While I have ordered new shims to attempt correction of the backlash, I'm working to machine my own in case they aren't available or have a long lead time. Two different dealer reps have said "there's a couple in the country ...," meaning the supply is low. They're also not cheap, but for how difficult they are to fabricate with my equipment, ~$10 is dirt. I can't imagine the pinion shim needing changed as both were identical, but perhaps that'll be necessary too. Anyway, TL;DR: I may be turning a solid pinion spacer while I wait for parts to arrive, too.
 

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I stand corrected: the pinion spacer is indeed a crush sleeve; setting the preload it seems to have crushed at least 0.003", measuring the backlash with the same shims. Also, the nut seems to be threaded the same amount, if that helps someone.

While I have ordered new shims to attempt correction of the backlash, I'm working to machine my own in case they aren't available or have a long lead time. Two different dealer reps have said "there's a couple in the country ...," meaning the supply is low. They're also not cheap, but for how difficult they are to fabricate with my equipment, ~$10 is dirt. I can't imagine the pinion shim needing changed as both were identical, but perhaps that'll be necessary too. Anyway, TL;DR: I may be turning a solid pinion spacer while I wait for parts to arrive, too.
I have done spacers to proper depth before. But only on extreme power levels. Much easier to use crush sleeve on 600 whp and lower. Even higher depending on how used.
 

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Discussion Starter · #31 ·
I stand corrected: the pinion spacer is indeed a crush sleeve; setting the preload it seems to have crushed at least 0.003", measuring the backlash with the same shims.
I wanted to clarify: this statement is misleading; crushing the sleeve won't affect the backlash/meshing, it will only affect the preload: this is why the service manual suggests setting the backlash without the sleeve, to avoid crushing it. 😊 The measured 0.003" must just be from differences in the ring gear thickness (vs differential carrier mounting flange location/depth/thickness) as the pinion shims were the same: only the pinion shim and side bearing shims (or a non-standard shim between the ring gear and differential case, but that's silly) can affect this backlash.

I have done spacers to proper depth before. But only on extreme power levels. Much easier to use crush sleeve on 600 whp and lower. Even higher depending on how used.
Good to know, thanks.
 
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