vtraudt

The 4.2 V8 C5 A6 is using the larger ZF 5HP24 transmission.
The 2.7T C6 V6 is using the smaller ZF 5HP19 transmission.

How difficult is it to swap the larger tranny over and bolt up to the 2.7T?

Any links to projecdts or DIY or instructions?

Or comments?

Bell housing adapter?
Mounts?
Prop shaft?
CV shafts?
Transmission control unit TCU? Coding?

mithrilG60

1) The 5HP24 is SIGNIFICANTLY bigger, it's why the wide bodies have a different transmission tunnel. It will not fit in a narrow body chassis.
2) Why would you want to do this swap?

vtraudt

Darn. So widebody only way. That puts the initial plan back on: 2002 Audi S6 Avant. Swap in 2.7T or RS6 engine (both upgraded to meet torque goal).

Why: Want high power automatic wagon (similar to current RS6 torque level of around 735 lbft (1000 Nm) to balance my 30 psi Allroad 6spd.

tester123

Different strokes for different folks!

Just want to say, that's totally awesome if you got expertise, time, effort and access/tools to do things like this.

I had to get this car on 4 jack stands to do the jobs I wanted to do (differential flange, trans, gear oil changes etc...) and that was a B!tch. Basically, lack of a lift.

Anway, good luck! Would love to see what you end up doing. Post pics etc., if you can so we can also be part of the dream :-).

MP4.2+6.0

FWIW, 4.2 gearing is higher IIRC, so may be counter productive. Front diff needs to match rear diff too so may be getting into more than you think.

Just visiting, but having owned one for first 140K miles and paid for the ZF factory rebuilt at only 100K, honestly the C5 and D2 4.2 trannies are probably the least reliable ones I can think of since the old 3 speeds from the Audi 5000 days. I realize maybe all folks can afford and it is a nice ride for its era. But if you were to read the D3 board over a lot of years where a lot of folks migrated over time from earlier D2 4.2's with the 5 speed, widespread recognition of that and general relief 6 speed AT is much improved. ZF also rev'ed the tranny with a bunch of fix up reliability improvements in the early millennium that neither Audi nor ZF publicized much; I found that out when I got the rebuild.

vtraudt

Is assume D3 is the '6 speed AT is much improved'?
"general relief 6 speed AT is much improved"

i could rephrase my question into: What is the strongest automatic transmission that can be swapped into a C5 narrow or widebody?