Help changing driveshaft flange on rear diff
 

HI Guys,

I wanted to see if any of you guys could help me with details on how to change the driveshaft flange on my rear diff without messing thing up, (I.E.- Torque specs and parts that should be replaced in the process). Diff is an '82 lsd. Bigger flange is needed to adapt to the driveshaft available from Mazdatrix for my TII trans swap. Or...should I just pull the rearend and take it to a diff shop?
https://cimg6.ibsrv.net/gimg/www.rx7...327d2f299f.jpg


Thanks in advance for your feedback.

So I have read mixed things about how this can be done without pulling the diff apart.

The FSM has a section that states you can reinstall your pinion flange in-situ and just torque the pinion nut to a certain value. I guess this torque ranges gets you back to required bearing preload.

Also read that to properly do this you need to measure bearing+seal drag and adjust to a target value.

At a minimum I would get a new OEM locknut and pinion seal, both available from Mazda.

And I will let the diff experts chime in regarding procedure.

Thanks for the reply. I will reach out to my local rear end shop. Noisy differentials suck!

My $0.02: Don't mess with a good rearend that does what you want. Better to get a custom driveshaft. I doubt there's anything special about the Mazdatrix unit.

I would lean towards pulling the third member and replacing the flange off the car. Taking it to a diff shop is the safest option. If you do end up trying this yourself, attached are a couple documents for reference. The v1 pdf is the archived thread (cleaned up) plus some additional information. The Miata interchange guide is just some other interesting info.