65 Corvair's Steel Front Diff Build

[Ramstrez]

Following this for sure

Thanks for all your work so far

 

[65Corvair]

My parts were machined.
On the left will be used on the driver's side, the right will be for the passenger's side to fit in the axle tube.

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Now that I have the parts in hand, I can do the finish work on the housing to get the distance between the machined part and the differential carrier bearing correct.

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[65Corvair]

Here are the prints for bearing/seal collars.
Overall, the collars work pretty good, the driver's side OD is a few thousand's too small, so it ended up being a clearance fit instead of a press fit when installing into the main diff housing.
The bearing and seal sizes work well, I was able to install both with the "right" amount of force.

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[65Corvair]

I cut off another 3/8 of an inch of the driver's side housing, and it is now flush with the main body of the differential.
Given that it was a clearance fit, I did not want to waste the parts I had. I drilled and tapped some 1/4-20 holes that went partially into the collar. Installing some set screws should be enough to hold the collar in place. I would have preferred to have a press fit, but the collar doesn't see too much load, so I doubt it would be an issue. I sealed the collar to the housing with a bead of RTV. The driver's side is now complete.

https://www.permatex.com/products/g...ltra-black-rtv-silicone-gasket-maker-3-35-oz/

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Next is to tackle the passenger side collar install.

 

[KJowner]

You could get it knurled to bring the size up.

 

[turblediesel]

You could get it knurled to bring the size up.

Or ping it evenly with a center punch.

 

[65Corvair]

Or ping it evenly with a center punch.

I tired the center punch method, it was too undersized for that method to work.

 

[65Corvair]

The passenger side collar is installed.
It was too much press fit for the 1/2 inch treaded rod, so I cut a slit in the tube and welded back together after it was pressed in.
The other cuts on the tube are superficial and happened when I cut off the Center Axle Disconnect from the axle.

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[65Corvair]

I designed up the passenger side mount, and will let sendcutsend.com work its magic and mail me my parts.
All the plates for the passenger side mount are 1/4 inch steel.

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[slowcrawlerZJ]

Thats some awesome ingenuity and fabrication.

 

[65Corvair]

My parts arrived and I was able to do a fitup. With my sendcutsend order, I also had some aluminum plates made to act a fixture for welding.
The normal aluminum diff has the passenger side mount perpendicular to the front mounting surface. I tacked up passenger mount at 90 degrees, but it gets pretty close to the starter. (Since I used a high pinion D30 instead of low pinion)
I will cut the welds and clock the diff housing down 3 or 5 degrees and see if that helps get more clearance to the starter.

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[u2slow]

You're in a prime spot to drop/shim the cradle down some. Even just a little could help. I've gone to 3/4".

 

[u2slow]

Actually, nevermind.... the diff and engine both are bolted to the cradle

 

[65Corvair]

Actually, nevermind.... the diff and engine both are bolted to the cradle

Yes, and I also have skid plates that go from the front cradle to the transmission crossmember that I don't want to create a spacer for.

 

[65Corvair]

I did end up rotating the passenger side mount 4 degrees to lower the pinion, however it was too low and caused the diff housing to contact the skid plates. Cutting and rewelding to 2 degrees seems to be just right. It gets it away from the starter some and leaves room for skid plate clearance. Using cardboard as a coarse flexible feeler gauge, I can slide 2 sheets between the diff and skid plate, so just a little less than 1/4 inch.

 

[65Corvair]

A bit of bad news, using a high pinion will not work (At least for an automatic 42RLE transmission) I installed the driveshaft last week, and it gets too close to the transmission cooler lines for my liking. The high pinion may work for a manual transmission, but I do not have a Liberty with a manual transmission to verify.

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However, I was able to find a low pinion dana 30 locally, and I began chopping.

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Comparison of pinion location, high pinion on top, low pinion on bottom.

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A majority of the excess weight has been removed.
The dana 30 front plate and passenger side mount are a direct fit from the high pinion to low pinion.

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[u2slow]

Thats a bummer. I had hoped the hi-pinion could have been used to reduce the half shaft angles. That would take some serious cradle mods I guess.

I recall JBA doing the steel front diff, and settling on the low pinion because of hi-pinion fitment issues.

I briefly looked at using the 8.25", but it seems to be too wide a casting.

 

[KJowner]

If you replace the bent pipes on those lines with 90° fittings you will gain a lot of space.