Evan,

I owed you some pictures of the shift rod “windows” from my collection of parts. Here’s the 3/4 window. Pictured first is the junked trans and the second is from my own good condition trans

http://forums.pelicanparts.com/uploa...1513454350.jpghttp://forums.pelicanparts.com/uploa...1513454350.jpg

Next are the 1/2 windows and same order- first is the junked trans and second is the good trans


http://forums.pelicanparts.com/uploa...1513454528.jpg

http://forums.pelicanparts.com/uploa...1513454528.jpg

So you can see the junked trans does show some roughened edges like yours show. I wouldn’t be concerned about it

The junk trans also still has its mid case bearing races installed. I laid a precision ruler across the OD of each race and you can see there’s only a teeny tiny amount of separation between the ruler and the face of the mid case

http://forums.pelicanparts.com/uploa...1513454906.jpg
http://forums.pelicanparts.com/uploa...1513454906.jpg

That said/shown, I agree with Gordo that it is what it is. If the old races showed the same condition, I would say it’s fine

Thanks Gordo!

The races are nearly bottomed out to the depth rings, maybe a mm in clearance between the underside of the rings and the bottom of the case bore. They sit just far enough in for the retainer rings to drop in place just above them. I suppose that when I test fit everything for the first time I will quickly see if the alignment between the bearings and the races looks good or not.

Cheers! SmileWavy

Maybe not a big deal, I just don't want anything to stand in the way of good shifting when this box goes back together. It has cost a fortune!



Thanks Kevin! My mainshaft bearing race in that position definitely sits further into the case then the pinion shaft bearing race. I'm pretty sure that the races that came out were At different depths too but I can't be 100% sure. Even if I bottom out the races as far as they can go until the depth ring stops them in the case, the one race will regardless sit deeper in the case then the other. The races are different sizes (width) then each other so this is unavoidable. As you guys commented, its probably correct as there s really only one way to install them.

Sorry my pictures are vertical. That's how they posted from my phone. I'm an old fart and hate doing pelican stuff from the phone. Stuff I post from the laptop or desktop PC seems like it always appears how I need it to look.

No worries Kevin! Thanks for the pics.

Peter's "special tool" washer
 

So I'm finally at the point of setting up my diff. Peter Z's tutorial calls for a washer between the flange and the diff carrier so the flange will get locked to the diff:

http://forums.pelicanparts.com/uploa...1513808319.JPG

Now here is the part I don't get: the point of the washer is to make sure that the flange doesn't contact the bearing, and is only fixed to the diff carrier. The washer called for is 45mm OD and 35mm ID. Which is exactly the same as the two flange dimensions. :confused: The carrier bearing ID is 50mm, so there is no way the flange can contact anything else then the carrier-- drop it in place and it rests on the carrier where it normally bolts in place, clearing the bearing race completely. Is there something I'm missing here? I had no issues measuring preload with just the flange in place without a washer. Or so it seems.

The diff is the factory LSD if that matters.


http://forums.pelicanparts.com/uploa...1513812408.jpg
http://forums.pelicanparts.com/uploa...1513812408.jpg

Limited Slip - Might be an exception
 

Upfront: I don't know how the LSD trans works, or if preload is measured in the same manner as per a non-LSD trans.

On my non-LSD transmission - if I didn't use a washer behind the flange, the other side output flange would rotate, but the input / pinion shaft wouldn't (spider gears in the center of the differential rotated, but didn't engage or rotate the ring and pinion / shaft).

The spacer provides direct contact (friction lock) between the flange surface and a corresponding surface in the differential housing / ring gear mount. With the spacer in place, I could rotate one flange, the other side would remain stationary, and the pinion would rotate.

Rather difficult to visualize and explain.

BTW - some people us a simpler / more readily available spacer - a short, stripped piece of ~ 10 ga copper wire, bent around the 35mm diameter of the flange surface. Provides the same contact needed to engage the differential ring gear.


Gordo

Thanks Gordo!

Since I don't have an open diff, I wasn't aware that the ring gear won't spin with just a flange installed. Since I've never seen one in person, its hard to understand how the spacer washer allows the flange to lock to the carrier. I think I should stop thinking about that, as it is making my head hurt, but your explanation was a huge help!

In my case, with the factory LSD, turning one flange turns the entire diff as a unit, both flanges rotate the same direction, along with the ring gear. So it appears to me that the whole unit is turning on the loaded carrier bearings as it should, and that I should be able to get a correct measurement with my fancy new dial torque wrench. Like you, I love tools!

Illustration video of my installed LSD (cover not torqued, so almost no preload here)-- can anyone comment?

<iframe width="854" height="480" src="https://www.youtube.com/embed/HOiAroOYWho" frameborder="0" gesture="media" allow="encrypted-media" allowfullscreen></iframe>

http://forums.pelicanparts.com/uploa...1513850095.JPG

*poof*
 

Suddenly the fog lifted and the light bulb in my head went on! Of course an open diff is a completely different animal... the flanges are only connected to the spider gears, so turning one only spins the spider gears and the flange on the opposite side (and in the opposite direction.) The washer "tool" locks the flange to the diff carrier so that the ring gear and whole assembly turns together.

With an LSD, turning one flange turns the entire assembly: ring gear, LSD and all. Both flanges rotate the same direction if you rotate one. So the preload measurement can be made with just a flange installed and no special-tool washer, since an installed flange is locked to the diff carrier anyway. Right?

Someone will almost certainly correct me if I'm out to lunch! SmileWavy

Preload for LSD
 

Good description and video - I'm tracking…

I'm thinking you are correct and your bearing preload measurements are correct.

Gordo

Right, Evan.

So you are saying that there is no washer needed to lock the flange to the diff, since it is LSD? Seems to me that there still could be some movement.

I used a piece of 1/8" brazing rod bent into a circle for my washer.

How did you set your pinion depth? Didn't it change due to your insert?

For there to be movement you need to overcome the preload of the lsd, which should not be below 38# if memory serves.

The point of the washer is to make the flange have interference with the open diff. Normally when the flange is bolted down it doesn’t actually bottom on the diff.

The bearing races are still located at the same depth relative to the case and components. I expect there to be a small difference due to machining the case flat, but I'll check backlash and do my best with depth. I have a bunch of new shims as needed.

Back on page 3 of this thread post #57 shows how I tested my LSD. Factory spec is breakaway between 7 and 25 lb-ft. Mine released at 26 lb-ft. As preload is not more then a fraction of that, there is no concern about movement.



And thats the difference here: on an LSD diff the flange bottoms out on the carrier.

No, the lsd flange doesn’t bottom. It shouldn’t. If it does you have issues.

Wanted to look this up since my memory is garbage. 29-58 ft lbs is the acceptable range.

I definitely have issues, I just didn't know this was one of them! Probably me with wrong terminolgy. The 45mm part of the flange bottoms out like this, or seems to:

http://forums.pelicanparts.com/uploa...1513960960.JPG


(Edit: Peter Z sent me this.)
From the Carerra workshop manual. Is this not also correct for a factory ZF LSD from 1981? I have the factory workshop manual from 72-on and that has the higher numbers you mentioned.

http://forums.pelicanparts.com/uploa...1513961073.jpg

That looks like a 2 plate late LSD spec from Pete Z versus a 4 plate early one.

What year is your gearbox again? What year did the LSD come out of?

'81 SC. Its the original box, had intact paint marks on the nuts (both nose and diff cover.) COA listed LSD, so everything says this is a box as delivered from the factory. April 1981 build if it matters.

Happy holidays everyone! SmileWavy

Anyone have comments on the last couple posts?