Drive shaft advice needed

Hi!
Does anyone know about drive interchangeability? I need to change my driveshaft on 1998 A6 TDI 2.5 Avant Quatro Auto. What I have available is one the same car with a manual gearbox, which is
supposedly longer.
The other one is from the same Automatic, but with a 4.2L gasolene/petrol engine, which the dealers say does not fit either. Does anyone happen to know what the difference between a 2,5TD and 4.2gasolene driveshaft is? Are the differences insignificant or substantial?
Sincerely, Fred
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Fred, It appears that the propshaft for some V8's is part number 4B3521101E (Engine? Codes: ARS and AQJ), whereas you need part number 4B0521106F (covers 28 engine? codes) - since it's the same tranny taking the engine output, I'd doubt that the propshaft was built more robustly, the difference between the two is probably in the length of it (the 4.2 engine itself may be longer or shorter than the 2.5 TDi) /location of the support bearing/???. Have you consulted any driveline repair shops about repairing the shaft that's on your car? Audi seldom has part numbers for the CV's/CV boots/universal joints/support bearings, but that doesn't mean that they're not available. Asking the collective at Audiworld might give you an idea about what others have done. Cheers! Steve Sears 1987 Audi 5kTQ - Type 44 propshafts can be rebuilt 1980 Audi 5k 1962 and '64 Auto Union DKW Junior deLuxes (SPAM Blocker NOTE: Remove SHOES to reply)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.