Series I > Series II Differential Mount Studs Thread Pitch
 

Having trouble with transplanting the mounting studs from my Series I diff to the Series II i got that did not have the studs installed.

Getting the studs out of the S1 diff was easy but they don't seem to thread into the S2, the diameter of the hole is the same but they catch almost immediately, in that way bolts do when the thread pitch is different.

Has anyone run into this? Is there a part# discrepancy between these?

Do you have new studs?
Did you inspect them to ensure the lead threads aren't 'folded' over?
Sometimes machine programmers mistakenly run the threads before the chamfer and it results in a distorted lead in.

Odd that they didn’t come with the diff housing.

The parts fische shows them being the same. Are you installing the correct end of the stud in the diff?

I'm using the studs removed from the S1 diff, they have an 8mm nub on them that made them simple to remove. they are undamaged and still thread into the S1 diff with ease.

I've also inspected and cleaned the sockets on the S2 diff and they appear clean and free of damage as well, all sockets catch using any given stud and in the exact same manner.

The stud threads are M12 x 1.25, but based on the way they catch, I'd say the sockets are likely M12 x 1.50.

On a whim I've ordered a set of four M12 x 1.50 x 50mm bolts, they'll arrive tomorrow. I'll report back if I find that they fit.

Yeah, I was disappointed to find out this as well, but I've been hanging on to this diff for several months now so I doubt I'd have much luck getting them from the seller.

It's a nice S2 diff, 41k on it and in great shape. definitely installing the stud the right way, i realize how this all sounds :yelrotflm

mind if i ask the part# off the fiche if you have it? i was unable to find it on most of the resources i use.

Part No. 9YA9-01-208


you might ask forum member “Ash”. He’s the best source for OE Mazda part information.

alright, gotta say I feel a little silly now. the original studs work just fine, they just need a good hard twist and from then on they went in smoothly. :rolleyes:

thanks for everyone's help and patience, i am thoroughly embarrassed.

It happens.
Glad it worked out.