Rallye Rear Diff Part Number

[Hoppum]

I’ve bought a rear diff that may or may not be from a Rallye, the previous owner was sold it as a Rallye one but all he could confirm to me is that the P/N was different to the one on his Country. It’s 009 525 053 A, is it a Rallye item and if not what is from and would it be any use on a syncro aiming to run 250ish bhp?

Any help greatly appreciated [].

[Chris S]

That is a casting number & not a part number, the actual part number is stamped onto a machined flat area & is made up from either 9V, AOK, ARR or CBX followed by 6 numbers, its not cast in as the other numbers are.

If you can give us the part number then we can say what its from.

[Hoppum]

Ah ok, that’ll explain why I’ve not had any luck with google. Will get the actual P/N get get back to you.

Thanks.

[Hoppum]

KKF
2
009 525 069

Those are all I could find that wasn’t cast in, I take it they’re the ones you need.

Thanks for any help.

[Chris S]

Sorry but thats not a part number, have a look here,
the arrow 1 shows where the part number is stamped into the casing.

[Hoppum]

Damn! Ok will try again lol. Extra annoying as I don’t have the diff at home.

[Hoppum]

Ok found it after cleaning of some paint.

ACK or AOK then 21029 and then either a 2 or a Z.

Thanks

[Chris S]

The differential will fit the Rallye, but with your differential code of AOK 21-02-9
the VC unit will not fit the Rallye propshaft,
you must either change the VC unit from a 22mm one to a 25mm one, or change the rear donut to a 22mm one

btw, over the lifespan of the Golf 2 Syncro there were 3 different VC units fitted

18mm from 1986 to 1989 – Diff code 9v
22mm from 1989 to 28-10-90 Diff code AOK
25mm from 29-10-90 onward Diff code CBX, AAR, ARR, AOK

[Hoppum]

I see, so it’s not an actual Rallye one? Reason I ask is that I have normal Syncro that I’m hoping to fit a 16vT to so was planning to swap the drivetrain for the stronger Rallye items.

Thanks for your help.

[Chris S]

All the Golf 2 & Passat 4 cylinder rear diffs are exactly the same, at the rear its only the VC unit & donut which differs.

[Hoppum]

Ah ok, so it’s only the the actual VW motorsports Rallyes that have the stronger diff, I was under the impression that all Rallyes had stronger ones. Would I be better off with a Rallye V/C unit and donut or would what I have at the moment be ok?

Thanks and sorry for all the questions.

[Chris S]

What you have at the moment will cope (or not cope) Just as well as the “Rallye diff”, the same for the VC,

but at 250 bhp you are approaching the limit of reliability for the Syncro rear diff,

if you search through my photos

http://www.vwsyncro.co.uk/?arc=&page=1&size=3&tpxbasketid=&search=&sortby=filename&sortbydir=asc&cols=3&cmd=do_search&i=0&big=0&gotourl=&p=6.Photos_ChrisS%2F_&basket_params=&basket_params_index=&noflash=&video_or_image=

you will see the difference between the Road Rallye & the Rallye Rallye running gear – believe me thats another world

Rallye Rallye rear diff below, notice the lack of VC unit (not recomended for road use)

Please dont ask, as none of that very tasty VWMS stuff belongs to me, (I wish) & is at a secret location here in Holland, thats secret in that the owner does not want his whereabouts published on line, or in any other way.

Its enough to say, that there were a few members from on here that were allowed to tour the premises and just see the extent of the early 90s VWMS Rallye program,

Also the fact that of the 9 Golf Rallye cars on site, 3 of them were ex VWMS Rallys & had actually done the biz

There were things like carbon fibre propshafts, wheel hubs & drive shafts with 120mm diameter CV Joints (instead of 90 & 100mm items)

To give you some idea of what I mean just look at the size of the transfer box gears & then compare them to your own!

We were very privileged to be allowed into his storage facility & must respect his wishes over privacy, again before you ask, no nothing there is for sale, please dont even think about it! []

[Hoppum]

Do you think he’d be interested in selling…I joke haha. That certainly is some very nice stuff, I imagine that rare is an understatement.

So I guess once the limit of the Syncro rear diff has been reached, Haldex is the next step.

Thanks very much for the help, I really appreciate it.

[Chris S]

I wouldnt worry to much about Haldex, as normally its the front transfer box that gives up first.

[the bartender]

my car has had a stock passat syncro rear diff for 17 years now (10 of those being 300hp+), with the last 4 years being 400+, and my rear diff is still fine.

[Author]

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