M90 rebuild. M56 as parts ?
 

Evening all, i have a 300k mile m90 out of th project car currently and it works fairly well but syncro is just about gone on 1st and it makes all sorts of noises when it wants to.

I also really would fancy a taller 5th gear, the vnt turbo makes 30 psi at 2400 rpm, so it can handle it.

So im thinking of rebuilding it, does anyone have a source for parts, does anyone know what parts if any are interchangable with an m56 gearbox as they have a tall top gear.

Many thanks in advance
Will vg

I've briefly looked into this. The ratios of a M56 are different to the M90 so I'm not sure if the syncros will also be a different size, but it would certainly be worth a look. I am planning to get hold of a M56 (even a broken one) to strip down and compare at some point. I actually want to swap some of the M56 gears into the M90. Let me know what you find out.

Craig

Thats exactly my plan, there have been a couple threads regarding this idea , but noone seems to have pulled their finger out to actually find out!

I will keep this thread updated with my findings, pulling an m56 out of a v70 p1 next week.

Have you tried turbobricks? I recently read a post about this but can't remember whether anyone actually did it.

ive seen a post about it on turbobricks, but to no avail, do you have a link incase im talking about a different thread ?

http://www.turbobricks.com/forums/sh...d.php?t=170611

Page one has a "a friend had one built" post so with a pinch of salt and all that, but it does seem like they're very much interchangeable.

I heard when the M90 came out that they used the 850 gearbox internals in it , rather like when the 340 went manual , they put the 240 gearbox in on it's side at the rear coupled to a new final drive unit , It worked well even the ratios were the same .

Watching this one with interest too (who isn't...).

I've got some pretty noticable gear chatter/rattle on idle. I'm 99% sure it is gear chatter since it isn't there when cold and goes away when you up the revs (over 1k) in neutral or dip the clutch.

Trying some thicker oil soon - it you read the spec sheet for the volvo oil it goes very thin when warm which is why im assuming my noise isn't there when cold; 1st to try is the next one up in castrol's range then a mix i found on a bmw forum since it seems to be a common problem with them too when they do silly things to the stock setups (I have a solid flywheel and unsprung clutch - amazingly it is perfectly mannered and easy to shift and take off, only problem is the gear chatter which was there prior to the swap but has got worse without the DMF to take some of the shock).

I am tempted if a change to a thicker oil doesn't fix it to buy a 2nd hand m56 and get a trans shop to swap the gearset over. I could also play with the ratios this way - quite fancy a longer 5th :engel016: and shorter 1st/2nd :teufel021:

Any one else fancy taking the plunge 1st... :tounge_smile:

PP

the gear wheels are massive compared to other cars , more like tractor ones so have inertia the rattle is not detremental

Thanks for that.

Out of interest anything i can do do quiten it down in you experience? (Aside from turn the radio up or fit an asbo loud exhaust to drown it out :tounge_smile:)

It's pretty annoying.

[btw sorry OP]

PP