can someone give me some info on the possibility of using a diff from another manufacturer and matching it to the standard front diff in my 4x4 saff?
the question really is how accurate do the 2 ratios need to be,
for example-i have a front diff ratio of 3.64 would it be imposssible to use a rear with a 3.7?
if they do need to be spot on is there options to change ratios?
many thanks
rob

 

Why do you want a different rear diff?

 

i just like the idea of doing something a bit different,i enjoy the engineering side of things as much as anything,it gives me something to think about and if i can improve reliability whilst doing it then its a bonus

 

I think you are on a bit of hiding to nothing really mate, the logical step for a 4x4 is to go to a 2wd rear diff, 7.5" instead of the 4x4 7", 108mm drive shaft flanges instead of 100mm, much stronger & a direct swap apart from taking 1/2" off the 2wd case, or swap to a 2wd rear beam. The 4x4 diff is 3.52:1, where the 2wd is 3.64:1 , it can be swapped out without meddling with the centre diff as it will be able to compensate for the tiny difference without damaging the center diff, it is what is fitted to my Escos.

Rear diffs generally are not a problem on 4x4, you would be better off looking to sort out the front diff that is notoriously weak!

If you do want to mess with rear diffs, the easiest way would be to get a new drop gear made up, although I don't imagine it would be cheap?

 

im already running a quaife atb 7 1/2 rear diff in a 2wd beam,its good enough but not different which is what i like,if those ratios you have mensioned are correct i should have no problem?
i also have a gtr gearbox and can run full rwd,would this help compensate for the difference or just cause problems with the centre clutch?

 

I couldn't comment on the skyline box mate, I don't know enough about how they work. If you fancy somthing different, have a look at this?:
https://passionford.com/forum/ford-r...-rear-end.html

I have the same set up fitted to my 2wd saff, it's pretty much indestructable!

 

that is just what im thinking of doing!same as rods running!what model is the diff from?

 

Not sure, but I have a non-powerlock diff spare if you want to borrow it to size it up?

 

cheers i will bare it in mind,gonna try and do some research first,
thanks for your help

 

Bear in mind you can get a Ford motorsport 9" diff for about 2.5k that is pretty much a direct fit as well, and again pretty indistructable!

 

2wd and 4wd use as close to the same ratio it really doesnt matter. Stated figures being 3.64 and 3.62

Although how that actually happens is beyond me as teeth count are likely the same.

if you want different f/r diff, then it can be achieved if you alter tyre sizes so the input shaft speeds appear the same to the centre diff ( ie front and rear propshaft speeds )