what is the most common failure of a rear diff?

is it because of the casting flexing?

reason i ask is because i was sold a 4x4 rear beam and diff as a 2wd item (didnt know any better at the time as it had the 3dr swingarms and rear arb...)

anyway, i am hoping for around 400ish bhp when the 3dr is up and running so thinking about getting a strengthening plate made up.

or failing that, i have a spare diff that i will get welded lol

 

pinion teeth breaking due to too much torque

or ask jb

 

isnt that something to do with the case flexing tho?

or not lol

 

no mate, i think you are thinking of the front where the pinion climbs the crown wheel teeth because the casing flexes

resluting ni the thick walled casings available form various leading providers of thick walled ford front diff manufacterers

in the rear you either live with the 7.5 inch diff (you've got the 7inch one) or yougo up in size to a 9 inch of a jag diff, the bits that you can uprate aren't the pinion or crown wheel

with 400 brake and rwd i don't think you'll give it nightmares, but a step up to the 7.5 inch diff (you'll need the 2wd shafts and outputs etc to go with it if you want to upgrade to the 2wd cossie stuff) would be the next step up from the likes of a granada (the 24V has an lsd in it)

 

is the granada (the 24V has an lsd in it) better or the same as a 3dr 2wd 7.5

 

i think the granada one is a 3;6 to cossie 3;9 better for bottom end i think, any one know where i can get one?

 

ah it must have been the front diffs i was thinking of then.

i have thought about changing to propper 2wd stuff, but that means changing the hubes etc too, so may as well get a complete 2wd rear beam etc.

but i cant be arsed nor have the spare cash at the mo so ill stick with the 7" and if it blows, get the spare welded lol

 

the granada 24V is a 7.5 in 3.62:1 with lsd and 100mm output flanges
the scorpio 24V is a 7.5 in 3.62 without lsd and 100mm outplut flanges

the 7.5 3.92:1 diff's are found behind the dohc engined sierra's 90-92 spec vintage, again with 100mm output flanges
the dohc 4x4 cars also had a 3.92:1 front diff

 

good info mate, looks like i'll be going breakers lol

cheers

 

what dohc sierras had a 7 1/2 diff?

the 2.o xr4x4 surely be a 7in

and a 2wd ghia/gls surely isnt lsd ?

 

Most common failure at the moment appears to be a Nordic trait of putting a 7" diff in a 500bhp RWD cossie and expecting it to last longer than 200 yards

 

all of the 2wd ones did, but in a 3.92:1 ratio

yes, but, again, in a 3.92:1 ratio

nope, you are correct there

although some granada's had the towing pack, which included a 3.62:1 7.5 inch lsd diff

and some had the taller 3.36:1 diff in them

 

some useful info there mate

 

when it's cheaper to buy a whole car for the diff than buy the diff on it's own, it's taken a lot of cars

i even bought a diff from sweden, but it was worth the money as it was a 3.14:1 7.5 unit

138 mph in 4th @ 6000 rpm

 

ive had a few sierras myself,gutted how many ive scrapped now