hey guys, ive just picked up a 99 audi a4 2.8 quattro off a friends dad for cheap...(i wasnt going to but i found the rear diff. on ebay with 40kmi for $350) so the rear differential locked up and needs replaced...

my questions are these:
1) the car i purchased is manual, the differential is off an 02auto, it looks exactly the same underneath, but id feel better if someone assured me this is true

2) when installing diff., anything i should look out for(a common problem?)

thanks and God Bless

 

The biggest thing I would say is to make sure that the final drive gear ratio is the same from a manual and an automatic differential. I would think most everything else should be the same.

 

right,...the newer differential is off a 2001 passat with 4motion(auto)...i searched consumer guide and couldnt find the gear ratios

 

Manual
3.500:1 -1
1.944:1 -2
1.300:1 -3
0.943:1 -4
0.789:1 -5
3.444:1 -reverse
3.889:1 -final gear

so i found the gear ratios for a stock 99 a4 2.8 quattro, but cannot find the ratios for a 01 passat 2.8 4motion-AUTOMATIC...any help?

also, even if the gears dont match completely, itll just be geared, minorly, different, right?