Resurrection of my CQ20V

[Bowie69]

A lot of the bearings are accessible just be removing the casing as I have done. Removing the bearings would need pullers and the like that I dont have, and frankly not that interested in doing at this point, as I am assured it was a lovely quiet box, with smooth shifting.

However, to do the bearings is not that tricky I reckon. Certainly the front diff carrier bearings will knock out and tap back in, the problem comes when you need to reset the diff again, into correct mesh, this requires new shims(which I dont have/are expensive) and lots of patience, and a dial gauge (which I do have).

If you change the pinion bearings, then you are into even more pain, as your variables have just quadrupled.

I've read the set up instructions, and while do understand, and have built up land rover diffs before, I just don't think it is something I want to mess with

Some of the bearings are more easily accessed, and literally would be knock in, knock out and done, like the rear output shaft, torsen support bearing, probably the layshaft bearing, all just standard stuff.

All the bearings are fine in this box, from what I can see/feel, so will leave well alone.

As for the bravery, I could pull one to bits in half an hour to as far as I went, assuming I had a rattle gun and no seized bolts, so there's no reason to be scared!

Removing the main/layshaft would be a little more work/complexity as you have to remove the shift collars etc, but even so, hardly rocket science.

[steve briance]

I admire your gearbox bravery!

Excellent photos and may give inspiration to open up one of the two boxes I have in the garage. One is very noisy, the other is only slighlty noisy, it would be hugely satisfying to be able to do something about it.

Have you ever gone further and got to the point of accessing bearings?

[Bowie69]

I will grab a photo next time I am up at the workshop.

The damper rubber had parted company from the steel, it was moulded onto the steel plate, and rust got in and blew it apart like any metalastic bush.very unfixable!

Snap ring fits on the output shaft casing, so the damper isnheld by 4 loctited bolts, the press fit onto the casing, and then the snap ring just make sure. Clearly Audi didn't want it going anywhere!

As far as what it does, it will prevent NVH in some form or another, damping out harmonics, it weighs a metric ton. I know some people just remove them, but I wanted it back

[Lago Blue]

Hi Bowie,

I'm enjoying the tour sir and have some questions about the rear diff's balance/damper and back-plate in posts 412 and 426 please.

What does this item do or provide, how do the plate and damper normally fasten together, and IIUYC how or why did it come apart or undone before you removed it or wanted it to?

Is it now un-fixable?

Does the snap-ring you mention sit inside the backing plate or...?

Could you please perhaps post a photo of what the flange looks like that this item bolts to?

Thanks for all the photos.

[Nuvo]

Perfect.

[Bowie69]

For seals, I just go to eBay with with the Audi part number from oempc. Search corteco + part number and find a cheaper one, sometimes you find genuine Audi stuff, but not sure it would be any better.

Any bearing/seal place will have then in stock, in general, I think, except maybe the large left side one on the rear diff. eBay is more convenient, my nearest bearing/seal place is at least an hour round trip.

Yep, just used a 17mm deep socket to for the seal, and I fitted it after the case was back together, so I could guide it down the shift rod. Tapped in very easily, as it is so small.

Drain plug I got from Just Kampers:

https://www.justkampers.com/113-301-...6cefq73pjvda5/

[Nuvo]

That's brilliant. Thank you very much for taking the time to detail the replacement of the selector seal.
I like the fact that you were able to remove the seal with just a screw driver. I assume you used an appropriately sized socket to press the new seal in place?
What supplier did you use for the various corteco seals you ordered?
edit: Can you quote me the part number for the classic beetle drain plug too please?

[Bowie69]

So having seen the state of the insides of the gearbox, and given it is too big for my meagre parts washer, out came some heating oil on a brush, followed by brake cleaner and an air line. Result was a lot cleaner gearset:

IMG_20200925_113310.jpg Most of the gunk was allowed to dribble down and out through the front diff casing, which is obviously still open.

It's not perfect, but will certainly do.

Bearings all seemed OK, be grateful for any input on the synchros, if you can see well enough here in these pics.....?
IMG_20200925_112934.jpg
IMG_20200925_112857.jpg
IMG_20200925_112728.jpg

It'd all buttoned up now, they looked OK to me, but I am no expert on these things!

Putting it back together was just a case of lining things up and a few sharp taps from the rubber mallet to get things seated. I used 'DIRKO Gasket Sealant ' as the sealer, seems to get good reviews....

Then it was time for the centre diff to get put back in the casing, but first, I needed to remove the old damper backplate. Thankfully the bolts came undone fairly easily.

Getting it off, was more involved, and I called on lumpy and chisel to get it to move. There is a snap ring holding it on as well, and yes, I did remember to remove it first

IMG_20200925_121953.jpg

Torsen in:

IMG_20200925_123415.jpg

More Dirko and bang it back together (more mallet action).

It was at this point I forgot to take any more photos, doh. But have reinstalled front diff as well as the new damper.

I'm stopped at the moment by the rear output flange seal, which somehow I missed ordering (it is not on OEMPC, I think), should arrive this week, and can fully button it up, degrease and start shooting paint at it.


I've lost count the number of cans of brake clean I have used, but it is a lot!

[Bowie69]

So, on to other things.....

I laid down a coat or two of etch primer on the rear diff casing, which was surprisingly dark grey, but no bother.

IMG_20200925_101852.jpg

Went on really well, and a good build with the UPOL stuff.

Spent a bit more time prepping the diff/gearbox flanges, and getting them ready for paint, and primed them up too.

Once that had gone off, some UPOL gloss black top coat (the rear diff came out the factory painted black):

IMG_20200925_153048.jpg

Pretty happy with how it came out.

Those are the gearbox flanges -as the box will be painted silver, the flanges *have* to be black, right?

With a black diff, the flanges must be silver also, right?

IMG_20200925_153057.jpg

....and while you have the paint cans on the go, may as well prime and paint the steering rack.


IMG_20200925_153709.jpg
My masking left a bit to be desired on that one!


So that got me this little lot:

IMG_20200925_153713.jpg
Really quite pleased, I do hope it stays on....

[Bowie69]

Ok, spent a bit of time on this today..... I hope to address the issue with the shifter seal for you Nuvo

Today I used my new 3/8 drive TX45 to undo the the casing for the main gearbox, that was nothing more than undoing all these bolts:

IMG_20200925_104838.jpg

Once done, you lift the case off (well, tappy, tap, tap with a mallet).... and get:

IMG_20200925_105429.jpg
Looking at that, I expect you can see the reason I wanted to disassemble this, and give it a good clean.

So, now we have the gearbox casing off, after a quick clean, lets take a look at the shifter seal:
IMG_20200925_110154.jpg
As you can see it is really thin, as I had the shift rod out, I just levered it with a screwdriver and out it popped. There was some corrosion behind the seal, cleaned up with a bit of brown scotchbrite.

IMG_20200925_110342.jpg


This is the new seal, waiting to go in:


IMG_20200925_110212.jpg
Then I forgot to take one of it actually in place.

So, given how small it is, I can't see you getting in there with self tappers, it is specced as:

Inner diameter 1	16 mm
Height 1	6 mm
Outer diameter 1	24 mm

Perhaps you could get in there with a seal pick? I really don't know.

*edit* found the missing image!
IMG_20200925_140454.jpg

[Bowie69]

Sounds involved, but I have time

[Nuvo]

It's right hand drive.
I did a little digging on the web I found information showing that the rear casing needs to be removed to allow internal extraction tool coupled with a slide hammer to remove it.
Maybe it is still possible to use the self tapping screws technique to save on labour time? Here's hoping.

[Bowie69]

Forgive me for asking, left or right hand drive?

[Nuvo]

Well I thought part of the steering rack sit directly above the the rear of the gearbox. When you mentioned that your has been leaking down the left side of the box that got me thinking that the left side of my exhaust has fresh fluid on it. I'll need to check this.

[Bowie69]

Shifter and steering rack are on different sides, are they not?