1.8t Quattro 4:1 center diff

[Jperez9627]

So I already have the machined washers needed for the install. Only thing I can figure out is if I should use my diff or buy another diff and use that one. I was on jhm's site looking at their center diff mod and they say that there is a certain diff that is garbage and one really good one. These washers are made for the pre face lift a4s (98-01.5 I think). Do these have different center diff than my 02 a4 1.8t b6? Any one who has done it have any suggestions? And how long does this install take?

[Gumby]

If it's a 5-speed it's the same transmission as a b5, and they should be fine to use.

[Matt Devo]

If it's a 5-speed it's the same transmission as a b5, and they should be fine to use.

This is not entirely correct. The center differentials in the early B5 5-sp are a two piece design, whereas the late B5 (01 only?) and B6 A4 5-sp are a 1-piece design; while the units themselves are interchangeable, the internals are not. So the OP must double check which washer set he has, and only install them in the corresponding center differential.

OP - FWIW, I've modified at least a dozen 01A center diffs, and haven't had any reports of failures with the older/2-piece unit.

[Jperez9627]

So there are 2 different set of washers? I actually got them off a member on vortex a few months ago. Would you guys recommend the older a4 center differential instead of mine. Which one is stronger/ more reliable. How would I be able to tell which ones I have? Is there a certain size or thickness? Is this process hard? I'm pretty good motor wise but have never played with my transmission.

[Matt Devo]

so you bought a set of washers off vortex without knowing which diff you have, which diff they are for, or what the process is to swap/install them? This isn't going to end well.

[Jperez9627]

I have a general idea how to install them. This is my daily driver so I can't have her sit more than a day. On the package it says "A4 Face lift" so I'm assuming this means my car. As for the diff I'm 95% sure it's the one piece as you stated above because my car is a 02. My fear is taking everything apart and having it take days to do.

[demonmk2]

I think the washers for the 5 speed work on both 2pc and 1pc diffs the 01e 6spd washers are different.

[demonmk2]

What did you pay for those washers? Just out of curiosity.

[Jperez9627]

It was like 55 bucks. I have had them 10 months or so and I haven't had a chance to throw them on.

[demonmk2]

Did you buy them form the guy who makes them?

[Matt Devo]

I have a general idea how to install them. This is my daily driver so I can't have her sit more than a day. On the package it says "A4 Face lift" so I'm assuming this means my car. As for the diff I'm 95% sure it's the one piece as you stated above because my car is a 02. My fear is taking everything apart and having it take days to do.

ok, then yes, you're good to go. Here's a DIY writeup for the 1-pc 01A diff: http://diffmod.plainbored.com/. If you're worried about downtime, I'd highly suggest you pick up another diff to modify, so all you have to worry about is swapping in the new one.

I think the washers for the 5 speed work on both 2pc and 1pc diffs the 01e 6spd washers are different.

this is 100% incorrect, as I've already stated. The washers for the two 01A diffs have a different diameter, different thickness, and different beveling.

[Jperez9627]

Did you buy them form the guy who makes them?

Yes I did. Another forum member gave me his contact information to purchase some. Let me know if you want his info if you want to purchase them.

[Jperez9627]

ok, then yes, you're good to go. Here's a DIY writeup for the 1-pc 01A diff: http://diffmod.plainbored.com/. If you're worried about downtime, I'd highly suggest you pick up another diff to modify, so all you have to worry about is swapping in the new one.



this is 100% incorrect, as I've already stated. The washers for the two 01A diffs have a different diameter, different thickness, and different beveling.

OK sounds good. I think I'm going to give it a go tomorrow afternoon. Hopefully I'm able to knock it out in one day. Thanks for the link. Now to choose what tranny fluid I want in there. Any one ever try penzoil sychromesh? The bottle says safe on yellow metals.

[Seerlah]

If you only want one day of downtime, I highly suggest you source one to mod outside so you can simply swap this diffs. And if you mess anything up with the mod on the center diff washer install, then your a4 would (or I should say "should") be 100% driveable still.

I also did this mod to my carba while back. $55 shipped washers off vortex. Held up strong with no problems so far (ie 150+mph, hard twisties...and I mean hard, etc). As mentioned above, washers are different for all center diffs. You sould have the 06a one peice if the label sent on your washers say "facelift b5). Only applicable to the factory 01-01.5 B5 A4, and 5 speed B6 A4. 01E also use a different washer.

[Jperez9627]

If you only want one day of downtime, I highly suggest you source one to mod outside so you can simply swap this diffs. And if you mess anything up with the mod on the center diff washer install, then your a4 would (or I should say "should") be 100% driveable still.

I also did this mod to my carba while back. $55 shipped washers off vortex. Held up strong with no problems so far (ie 150+mph, hard twisties...and I mean hard, etc). As mentioned above, washers are different for all center diffs. You sould have the 06a one peice if the label sent on your washers say "facelift b5). Only applicable to the factory 01-01.5 B5 A4, and 5 speed B6 A4. 01E also use a different washer.

So then I for sure have the correct washers?