Hi all,

I need help. I have MY98 and I bought Quaifie front diff. As this mod need remove gearbox and open it I want do more thing at same time like cutch change...
And... I have centre diff from STi V6 with cover so whole part and it look I need only remove end of my gearbox and put new on. But my friend told me inside that piece of gearbox is final drive witch is another for Sti and for EU cars. Is it true can I combine my box with that cover + diff?
Many thanks

Erik

 

Nope you can not do that, as the gearbox and diff need to be from the same car.

banny

 

Not quite. You need to have the same final drive ratios front and back, for obvious reasons. The drop gear is located in the viscuous diff section. Euro/UK cars run a 3.9:1 front diff with 1.1:1 drop gear and rear diff of 3.545:1 Jap cars usually run 4.11 or 4.44 front and rear diffs with a 1.0 :1 drop gear. The STi 6 runs 4.44 front and rear diffs in O/E form.

 

Just to add a bit more; You can easily swap the drop gears at the back of the box from JDM type 30 - 33 or UK/Euro 30 - 31. they fit the same. That means that in some cases. I'm thinking 6 speed particularly, you can change the drops and still retain the UK/Euro 3.545 rear diff.

So providing you have a JDM 5 speed box with 3.9:1 ratio in the front changing the drops will prevent the need to buy a rear diff to match when working on a UK/Euro 5 speed car.

That make sense to you guys? it does to me.

Good Luck all David APi Engines / APi Impreza
www.apiengines.com

 

Hmm I have headache
So if Iam right I can use that part with my MY98 gears just I need change drops?

 

Errrrr Yes, I think so !! I guess the vers 6 part is the electric centre diff?? is that right. That's the only reason I can think why you'd want to change.

However, I am not sure that you can graft the vers 6 back end from a TY754 type box [ MY99 on ] onto the old TY752 [ MY98 ] main case. The problem is that there is a locating shape in the casting inside the mating face of the TY754 back end and if the 752 5th and reverse gear mechanism doesn't sit snugly into the rear case you will have big problems.

Best to look carefully at the inside faces of both rear cases and if they differ then you have a problem.

Perhaps a better explanation of what you are trying to achieve will give us a bit more info to be able to advise better.

David APi Engines / APi Impreza
www.apiengines.com

 

No its classic type only not DCCD.
The only reason why I want is is stronger visco inside Sti. If I can swap just this one its fine for me.

 

Oh! OK, not sure that will work then, as there are also two different types of viscous; as an explanation, it is as if one is left handed and the other right handed. Thus they each fit in a different shaped case and I think that is where your trouble will lie.

Perhaps try to get an STi centre from a matching TY752 box is the answer??

David APi Engines / APi Impreza
www.apiengines.com

 

Iam not very happy from your answer
Nevermind if no I can live with OE diff + Quaife. Thanks for your advisement.