TC3 diff parts - compatiblity?

[Lonestar]

Howdy yall

remember when we were pillaging TC3 diff rebuild kits for our Stealth Cars? how the wheels have turned, eh ?!?!

I am rebuilding a TC3 atm to be a gentle runner. The car I bought came fully decked out with tons of blue (useless) bling, including lightweight alloy outdrives. I sourced some new alloy OEM outdrives and then disassembled the blued-out diffs... only to find out that the blue outdrives have the flat spot on them (to prevent the diff ring from rotating on the outdrive) whereas my brand spanking new outdrives require the diff rings WITHOUT the flat spot... after some investigation, both the flat/non-flat configurations are correct and it looks like it was a running change at some point. My issue is: I have bucketloads of flat-spot diff rings, but no non-flat-spot ones.

To clarify with pitchers:

Early flat spot diff:
- outdrive: couldn't alloy/steel find P/N but composite is 3908
- diff rings: 3906

Later non-flat-spot diff:
- outdrive: 3912 (this is what I have... twice....)

- diff ring: 6579:

Interestingly, one can find references to TC4 diffs with the flat spot rings, too... even tho the tc4 came after the tc3...

And OF COURSE the worlds re-re car uses 6579... meaning that there are only outrageously priced ones available on the market these days

So my Q to this fine audience here is: are there any compatible references, possibly non-AE, that can help as a more available (read: less expensive) substitute do 6579? another solution is to source some B44 diffs, but I mean c'mon this is getting totally ridiculous....

Thanks in advance for your help and take care yall

Paul

[juicedcoupe]

Possibly try this.

https://www.rc10talk.com/viewtopic.php?f=38&t=46849

[Lonestar]

Possibly try this.

https://www.rc10talk.com/viewtopic.php?f=38&t=46849

you rock - thank you!

[jwscab]

The rings are very hard, but you can use a Dremel and stone to grind out the D shape to make it circular. It's not too difficult. It also doesn't have to be super accurate, the rest of the diameter will seat the ring.

[Lonestar]

McMC still doesn't ship abroad in 2022... sigh....

The rings are very hard, but you can use a Dremel and stone to grind out the D shape to make it circular. It's not too difficult. It also doesn't have to be super accurate, the rest of the diameter will seat the ring.

Thaks Joe - didn't think about dremeling my way out of this mess... let me see if I can do a not-too-butchered job, I'll give it a shot!

Thank you guys

Paul

[GoMachV]

It might not be a problem but I would work slowly grinding those as not to work harden just a portion of the ring.

[Lonestar]

It might not be a problem but I would work slowly grinding those as not to work harden just a portion of the ring.

Thanks - will follow that advice too

[RogueIV]

My suggestion would be to file in the flat spot into the diff halves instead it'd be easier and you'd only have to do it once and be able to use both types of diff rings.

[jwscab]

You'd have to grind the diff halves, which are also super hard. But that is also a way to do it.

[Lonestar]

My suggestion would be to file in the flat spot into the diff halves instead it'd be easier and you'd only have to do it once and be able to use both types of diff rings.

Thanks for the suggestion I believe it would be more efficient indeed

I'm already concerned about grinding the diff rings .... I know for sure I will make a mess if I start working on the diff halves themselves

Thaks though!

Paul