Resurrection of my CQ20V

[Greg_S]

Brilliant write up and really interesting to see what it takes to rebuild the diff and gearbox. The whiteline is also quite close to the wishbone on my ABY also.

[Bowie69]

Thanks John and Greg, life changes for the better recently has allowed me a little more time to play with this, and other cars, so progress is swift at the moment, just hasn't been for the last 3 years!

[Bowie69]

So.... today saw final seals turning up, so, gearbox rear output shaft seal goes in:

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Followed by the output shaft, mit stupid mistake:

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The stupid mistake is this:

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That is looking through the plastic plug hole on the underside of the TorSen housing, that shaft is the output shaft, and it needs a circlip in the groove. Clearly this needs fitting *before* shoving it into the TorSen centre. Doh.

Tappy, tap, tap, and out it comes again, slide the circlip over the shaft, through the plastic plug hole, tap the shaft home, and some 90 degree circlip pliers gets it over the ridge into the notch easily.

It was much easier to lie the box down for this part:

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You can just see the ears of the clip, sorry, dark, flash and close up makes for bad photo.

Then, in with the plastic plug. I cleaned the o-ring up, and made sure the groove was clean for the circlip. Smudge of grease to help it go in, and push. When removing, you use an M8 bolt to pull it out, was also useful to put it back in:


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The circlip was an absolute pig to get out, but much easier to get back in, less corrosion I reckon!

Earlier this week, I realised, I had neglected the input shaft seal, it is fitted into this removable part in the front of the gearbox:


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Took a brave pill, and tried cracking them off (I have a natural dislike for torx or allen headed bolts....), and all three moved, so I removed it:

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Mmmmm, crusty.

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Also crusty.

Tapped the seal out from inside the tube a bit, then levered it out by twisting the screwdriver behind the seal:

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More crustiness.


A while later with some wire brushes, scotchbrite, and some brake clean, we have this, with a seal awaiting being driven home:


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After cleaning the box flange up as well, I fitted it back, noting that the drip hole is facing *down* (box is on its side at the moment):

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There's an o-ring behind there as well, which I hadn't realised, I fortified it with some Dirko....


Bolts went in with some loctite, as they had it on when I removed them, I am guessing now, but possible they aren't blind holes and could leak if you didn't seal the threads.

The source of all this gearbox work:

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It was when removing this for cleaning the outside of the box, that I saw how gungy the inside was, and decided to disassemble. Now the rest is clean, I cleaned this up and popped it in.

I then spent an inordinate amount of time cleaning and degreasing the outside of the box, as well as trying to remove any loose white corrosion, essentially prepping it for paint. This involved phosphoric and muriatic acid (at different times!) both of which seemed to help the situation.

It came out quite clean:

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However, now, I am at a conundrum.... do I paint it? It wasn't painted from factory, so now I am not so sure, despite having bought all the materials for it....

I suspect Audi put some sort of wax on them, to stop corrosion, as I keep finding traces of something like that, but really unsure if that is fact. So I guess I am throwing it out there for opinions! Paint or protection of some sort.... or nothing at all?

As a side note, I am likely replacing the fasteners, as along with the aforementioned hatred of torx heads, the plating was well past it, even before I dunked them in acid.

[Bowie69]

Oh, in other news - I tidied the bench a little!

[Bowie69]

Also, I wanted to note, that actually, these gearboxes are pretty simple beasts, designed for servicing. The seals are mostly replaceable without full disassembly, the three output shafts all while the box is in the car!

It comes apart simply, no pullers or the like until you start having to deal with the actual gear clusters.

So, as a starter gearbox, I'd thoroughly recommend pulling one of these apart, what have you got to lose?

[steve briance]

[Vorsprung durch Technik]

Excellent write up and pics, you've done a fab job!

[Bowie69]

yeah, I know, right? the bench was a hideous mess.

[nribs]

Hijacking Bowie's thread here for a minute. About 5 years ago I had a situation in my US CQ in which literally one moment to the next, the car would no longer stay in gear. Once in gear and under acceleration the car would work (and due to circumstances, I drove it this way for about a month) while I sourced a new box. I was fortunate and located a cheap and local low mile 01A from a sedan (taller 3rd-5th). After much research the conclusion was that the 'gear selector detent spring', aka "locking segment" had failed. Why or how, anyone's guess? I didn't abuse the car (what fun is abusing a 7A after all).

Point is, you cannot replace the detent segment with box on the car, and as long as I was dropping the box, the low mileage upgrade was the route I took. It allowed me to replace all the seals that Bowie did here so exceptionally. One thing I remember about that job was the difficulty removing the locking circlips for the flanges. I spent over an hour with a cheap (Craftsman) pair of ring pliers. Could not get them off. Had to have a mechanic friend with SnapOn or equivalent get them off.

I was determined to fix that box, erroneously thinking that the 01A had resale value, and bought the replacement locking segment (a cross-listed Porsche P/N btw for those curious) opened the box and sure enough, the little piece of the spring failed.

Fun times....

[Bowie69]

Good write up and pics.

Which circlips do you mean? The front outputs are removing by winding a pair of bolts into the flange against the casing, and the rear has a single circlip, accessed via the plastic plug hole.

[nribs]

Output on the tranny and input on the rear dif. The only two that require circlip plier to remove.

[Bowie69]

Weird, must be a slightly different rear diff -mine uses a staked nut to hole the flange on.

I know some of the front diff outputs used a bolt, instead of the internal clips ( I am grateful they aren't the bolted version), but is there another version then?

Hmm, quick google, is yours this sort?

http://www.brokevw.com/020flange.html

[Bowie69]

What feels like a smaller update today, the various gearbox/diff mounts all got cleaned, etched, and painted silver:

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Quite happy with how they have come out.

....and I made a decision on the gearbox finishing:


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In etch, and in top coat:

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Mit fan heater to raise the temperature just a bit.

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The output flanges are now silver, forgot to mask until too late, oh well

[Vorsprung durch Technik]

Looking really very good indeed!

[Bowie69]

Bit more time yesterday to get some some smaller jobs done....

The bracket for the diff lock actuator was looking decidedly past it (NLA from anywhere it seems), so, after some CAD, careful cutting out with a grinder and step drill, what felt like it should have taken a lot longer than it did with a hammer and various bending methods, I ended up with this:

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Little more hammer tweaking required there, but 99% done. Other views:

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And a comparison with what was there(!):

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I used 0.9mm stainless sheet to make this, which seemed to bend up pretty well, and was able to reduce the metal where the return goes around the curve quite easily. I didn't make a hammer form, just used a regular bodywork dolly in a vice.

So after a final tappy-tap-tap with a hammer and dolly, to straighten out and little ripples, it was given a scotchbrite treatment and it is ready to go on the car when the diff gets swapped in.