Hi, Just wondering if somebody could give me some advice on building a hybrid gearbox to fit the YB cosworth engine RWD, i have the mt75 2.0 rwd box and know the cossie flywheel fouls it and i need a mt75 4x4, so all im wanting to know is what exactly do i need to modify it to fit.. Propshaft mod? clutch mod? gearbox shaft mod etc? could somebody tell me everything i need. Thanks in advance folks!

 

surely someone must know on pf ?

 

I have no idea at all, but thinking out loud...

Are the two MT boxes you refer to different (excluding the obvious 4x4 bit!)

Are the starter motor appertures on the same side of the 'bell housing' (even though MT75's don 't have a removable bell housing you know what I mean) you may need to swap the front cases over?

If you have to use the 4x4 Cos flywheel then you will have to use the 4x4 starter, clutch cable etc - well, I'd have thought so anyway?

The input shafts - are they different in any way? If they are then you may need to swap that over too?

You would probably need the propshaft from a 2.0 8v DOHC Sierra seeing as the basis of your gearbox is from a DOHC Sierra (okay, it might actually be from a Granada but the prop might be longer/shorter - I can't remember -also make sure the gearbox crossmember is form a Sierra - the garanada one does not fit.)

Like I said I have no idea and all what I have written might be total bollocks but you have to start imagining what might be different and checking it out for yourself. I'm sure I read of one white 3 door (adams105e - username?) where the geezer had done this but I might be wrong.

Good luck!

 

Oh, and I'm not sure if the front end of the 4x4 8v DOHC Sierra MT75 box is different to that of the Cosworth 4x4 MT75 box - something else to beware of - make sure you get a propper Cos4x4 box to rule out any annoying mix ups.

 

Hi mate just see this !!

It's me you were thinking of , yes I did make the gearbox but never fitted it . Only cos I got another 4x4 box and put that in

 

Right so basically what I did was............

I had a dohc 2.0 mt75 rwd gearbox.

And

A fucked 4x4 YB cos mt75

As you already know you can't use the 2wd because the flywheel won't fit inside even though it's the same bellhousing pattern .
Also it hasnt , really got a removable bellhousing as such , it's half the gearbox !
I removed the whole front half of the 4x4 gearbox and then
Put that onto the 2wd mt75 .

This Worked at fine for me as my car is 4x4 anyway so that meant the , starter and clutch fork stay on the same side N/S.

You might encounter problem if you try to use a 2wd starter ,
But I should think ( don't hold me to this though) that the 2wd sump should be ok as its quiet small in size compared to a 4x4 sump .

Also make sure you get a 4x4 Yb box NOT a v6 xr4x4 as the bellhousing pattern is wrong .

 

thanks for the input lads really appreciate it

 

I don't get it, cosworth made rwd cars so why not just use that box? What car are you trying to fit it in?

Are you thinking yb 2wd in to something else?
I have an mt75 with the front of the bellhousing lopped off if you need it for bits?

My friend has adapter plates to get then RX8 6 speed rear wheel drive box to fit yb, zetec etc...

 

The T5's go for a good few quid now don't they - a bit of thinking outside of the box (no pun intended), and if you have certain bits lying around it's a cheaper way to get a Rwd box?

If your not running masses of power it should be fine?

I think your main problem will be sump related.

Could end up being a lot of messing but if you are handy with tools/alloy welding and such it won't be too much of a bother.

The RX8's gearing/ratio's lead to a bit more of a ball ache with diff's and stuff don't they or am I thinking of something else?

 

The Rx8 is low geared as the rotary spins to high revs but changing diff ratios brings that back....I think I saw someone saying that a cossie lump is 120 mph in sixth at 7000 rpm but super short gearing which can be useful. I would lob in a T5 if that doesn't suit.

 

hi i have a yb going into my 3 door rep well i say rep its now 99% cosworth minus the rear axle & diff, i have bit the bullet and bought a T5 box mad money like. yeah the mt75 does work just a bit of clart on but could deffo save you quite a bit of cash. cheers everyone for the replies tho