Building a better Vanagon automatic transaxle

[MarkWard]

The inner gear has less teeth, so the marks wouldn’t stay aligned. From memory the marks show the outer face of the gears.
_________________
☮️

[vwhammer]

Mark is correct.
If you look at this animation and try to follow an inner tooth and an outter tooth that are mated together, you will see by the time they open up and get back around where they should mesh again the outer tooth will be behind 3 or 4 teeth

[vwhammer]

Ok I am officially confused.
Here is a diagram that I will be referencing in my statement/questions below.

I am running the Audi forward drum/clutch assembly (554) with the 4 gear Audi planetary(582).

As is necessary, I am also running the Audi sun gear (612) that works with the 4 gear planetary in the forward Assembly.

I got all of that in the transmission.
It comes time to install the VW reverse planetary (584) and it will not go on.

The teeth are different and it will not mesh with the Audi 4 gear sun gear (612).

You can not use the Audi reverse planetary (584) because it will not mate up with the VW Reverse ring gear. (594)

You then can not use the Audi reverse ring gear assembly because the internal splines on it (inner splines on part 604) are bigger and will not mate up with the shaft on the diff.

So how does this actually work?

Some pics for reference.
Audi forward drum and shell installed with Audi forward planet and sun gear.

VW reverse planet (left) and Audi reverse planet (right)

The VW reverse planet with not mate with the sun gear in the previous pic.

I should also note that you can not run the VW forward sun gear in the Audi 4 gear forward Planet because it also does not mate up.

What gives.
How have people been doing this?

[MarkWard]

I would imagine you have to use all of the Audi parts. At least those parts that mesh with the sun gear top and bottom.
_________________
☮️

[vwhammer]

Well this is the problem.
There is no combination of parts that will allow you to use the upgraded Audi bits (4 gear forward planetary) with the VW trans and diff.

I anxiously await the solution since it seems several people have done it.

[h00drat]

I’m not sure what your issue is. I’m running the Audi 4 planet system and it mates up fine. Switching to the Audi 4 planetary system is one the main reasons for this swap, so you shouldn’t try to make the VW 3 planet system work.
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[kourt]

In my case, I used a special reverse ring gear, 090 323 370, to make it work. I had to buy that ring gear special from GTA (as noted in my build on 5)

I hope this helps.

kourt

[MarkWard]

[Gruppe B]

[vwhammer]

None of what you mentioned is what I am having issues with.
I sat yesterday and reread this whole thread and didn't see anyone having the same issue that I am having.

Perhaps the part that kourt mentioned is the magic piece of this puzzle.
It is a different part number than both the van reverse ring gear hub and the Audi rev ring hub that I have.
Originally it was believed he needed that piece because he was using an early Audi trans but maybe there are just some versions of this trans that require that part.

I will tear it all down and take more pics to properly illustrate the issue I am having.
I may also call german transaxle and see if my issue makes sense to them and if they have a solution.

[vwhammer]

Kourt,
Is that part number you listed the actual ring gear (part 594 above) or part 604 in the diagram above?

[Butcher]

FYI, there are two different 2nd gear ratio's on these transmissions. I'm certain that is why some work and some do not. I do not believe it's a 4 planet gearset issue but a ratio issue.

[Gruppe B]

[h00drat]

[vwhammer]

[kourt]

Howdy,

The ring gear I reference in my post was sold as a whole unit (the outer ring gear, part 594, and the inner annulus, part 604).

The annulus is held in place by a circlip and is swappable.

The annulus that came with my GTA ring gear fits the 1982 4-planet Audi internals, while also interfacing with the turbine shaft of the Vanagon. That annulus is also shallower (I think I'm remembering that correctly--don't hold me to it) in its bearing surface.

You can see the original annulus differences here:

The 1982 Audi annulus on the right will not even fit the turbine shaft of a Vanagon, and would also prevent proper endplay when the trans + diff are mated.

Note that neither photo here shows the true 090 323 370 annulus.

GruppeB and Butcher are right, there are two flavors of ratios out there. Here's some numbers.

Audi 5000 turbo automatic through 1983:

1st: 2.55
2nd: 1.44
3rd: 1.00

Audi 5000 turbo automatic from 1984:

1st: 2.71
2nd: 1.5
3rd: 1.00

Vanagon 090 automatic:

1st: 2.71 (late), 2.55 (early)
2nd: 1.5 (late), 1.44 (early)
3rd: 1.00

In my case, I put 1982 Audi internals into a 1985/1991 Vanagon transmission, which may explain why I needed a special ring gear, but GruppeB did not have those same results.

kourt

[vwhammer]

I am at work at the moment so I can't really look into anything.
I suspect the issue I am having is because I have parts from the 2 different gear ratios.
The used trans that I bought to rebuild supposedly had been rebuilt by the previous owner.
based on the box of parts that he gave me it was apparent that he had a couple of transmissions that he was getting parts from.
It is very likely that he used the taller geared internals in the later case.

I still have all the parts from the trans that was in my van when I bough it so I should have the right parts.

[vwhammer]

Ok everyone can rest easy.
I've sorted it out.
Pretty much it was exactly as I guessed.

Someone at some point put the 2.55/1.44 gear set into this transmission.

Fortunately the box of parts that I got with the trans had the reverse ring gear in it from the 2.71/1.5 gear set.

So these are the three pieces that I have available.
This is part 604 in the diagram I posted earlier.
the first one is the piece from the Audi as evident by the 087 that starts the part number cast in the piece.

This part fits in the ring gear for the Audi and the 2.71 Van gear set but the ID is too big to fit on the Van Diff splines.

This is the 2.55 van reverse ring hub.

You will notice it starts with an 090 instead of the 087.
Well I guess technically it starts with an A but you get my point.
It's a van trans part.
It fits the van diff but does not fit the larger Audi or van 2.71 reverse ring gear

This last one is the part I need.

No "A" at the front and ends in a B but also has the 090 at the beginning.
This is the hub for the 2.71 van reverse ring gear.
It fits the larger Audi reverse ring gear but naturally fits the 2.71 van rev ring gear.

Here is the larger Audi hub in the smaller van ring.

no worky.
Obviously the larger van hub also fits similarly in the smaller van ring.

Here is the smaller van hub in the larger ring.

Here is the difference between the big (2.71) ring and the small (2.55) ring.

So obviously, once again, the big ring and the big van hub fit over the 4 planet Reverse planetary and also fits the splined shaft on the Van diff.

So that's one problem solved.

On to something else.
I noticed in the Bently that there appears to be one extra friction and steel in the 1st/reverse clutch pack that appears to be smaller than the others.

Maybe I did not look hard enough but it seems none of my transmission have this.
What is this?

The last issue that I came across was likely on account of some slightly out of spec pistons that seem to be all over in the van trans rebuild world.
With my old parts you can see that the little relief valve in the 1st/reverse brake piston lines up real nice in the shell

With the new piston it did not line up so well.

I made an executive decision and decided to take a file to the hole to open it up to clear.
It worked a treat but I did not get any pics of the final product.

Well I think that's all I have come across that I have had to sort out.
I hope to get this thing wrapped up tomorrow.

I need to buy a smaller torque wrench so I can adjust the brake band.
Oh speaking of brake band I got my HD kevlar band from Matt Steedle and swapped that out for the plain jane stock piece. (sorry no pic of the part)

[h00drat]

Ah sweet. Glad you have the right part. I have the same 373 B or 373 8 hub. Whichever it is.
_________________
<<Tyler>>
1987.5 Wolfsburg Weekender / CHC / 2.0 ABA
CHC Top Thread
Engine Conversion Thread (2.0 ABA Swap)
ABA Swap - Image Gallery
Auto Trans Rebuild - Image Gallery

[vwhammer]