Hi

Can anyone tell me if there is a 7.5” Sierra diff with a 3.14 ratio available or if 7” crown wheel and pinion will fit into a 7.5” casing ?

I've heard of 7.5" diff's with 3.14 ratio's, but never actually seen one for sale (I suspect they were like rocking horse poo, even when these cars were new)

I believe the 3.36 raito 7.5" diff's may have been a little more common in europe, but the 3.64 is far more common - have you had a look here:
https://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=85080 ?

or here for more info:
http://www.super7thheaven.co.uk/components/sierra_rear_differential/




I don't believe you can fit a 7" CW&P into the larger casting - they aren't interchangeable like that

but you can mount a complete 7" diff casing in pretty well an chassis / read beam meant for a 7.5" - all it takes is some different bolts and spacers
(the 7" uses 2 long through bolts in place of 4 of the short ones on a 7.5" )
quite a few kits were made to fit either size diff in this way - including my rush

only issue you might have is with driveshafts - it just depends which type and what size you have now (the 100mm bolt-on type will be the easiest, as they are the same on both diff types)

7.5 gears are much biger than 7,
also main gear 7.5 use 12 bolts, 7 use 10 bolts.
Also 7.5 center part mauch wider compared to 7
because diferent size of gears i gues it not fit correctly.

i tried 7" gears put to 6.5 diff, almost indentical, but have ~5mm pinion gear offset.

Ok thanks for the info

quote:

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Originally posted by fregis
7.5 gears are much biger than 7,
also main gear 7.5 use 12 bolts, 7 use 10 bolts.
Also 7.5 center part mauch wider compared to 7
because diferent size of gears i gues it not fit correctly.

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