How do you tell if it's a 7" or 7.5" diff?

And did any Sierras come with a 7.5" diff?

Reason I ask is I thought that the measurement refers to the top mounting width, which on mine is around (but not exactly) 7.5", whereas the bottom mounting width is 7" near enough spot on.

It's from a 2.0 DOHC LX (1992) so I was expecting a bog standard open 7". It's got push in shafts incidentally.

Thanks,
Pavel

May help mate Linky

Cheers Rich

7" on the left
7.5" on the right

the top mount on the 7" has 1 long through bolt, the 7.5" has 2 short ones into tapped holes

the DOHC will probably have a 3.92 diff (7" axle code 'D' on the vin plate) or a 3.91 diff (7.5" axle code '9' on the vin)
diff code info here: http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=85080

quote:

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Originally posted by PSpirine
And did any Sierras come with a 7.5" diff?

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The 7" & 71/2" measurements relates to the crown wheel size, the top mount measurement is a coincidence.
Photos above are correct.
There was a little known 61/2" diff and a 9" motorsport one.

So an even more stupid question from me on Sierra diff's

Have bought an MK Indy and want to switch the diff to LSD. I can't quite see whether the current diff has single long bolt or not (am going from memory - there's every chance that on further inspection I may find a bolt head on one end and a nut on the other, so apologies for wasted bandwidth if so) - in the meantime does anyone know whether the MK Indy was specifically designed for either the 7 or 7.5 inch differential?

Thanks
Perry

^^ I could be wrong but I though the indy needs a 7" diff



the other thing to check while your under there is the type of driveshafts you've got (bolt-on or push-in)
assuming you want to use the stock ford LSD - these all need bolt-on shafts

(cars with bolt-on shafts should have disc brakes, ones with push-in should have drum brakes - but it could be using an adapter kit for the brakes or hybrid shafts etc.. so its best to check)

Thanks mcerd1, this is what I was expecting I think

Driveshafts are definitely bolt-on, with disc brakes - I'm only wanting to change for stock sierra LSD and keep prop/driveshafts

Maybe I'll weld-up the current diff for anti-social drifting at a future trackday I doubt a non-LSD 7" diff is worth much?

Cheers
Perry

Right - it's defo the larger 7.5" one that I've got!

Are my shafts interchangeable with a 7" diff? They're push-in.

Thanks all,
Pavs