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View Full Version : My Tranny Swap



JettaRedII
03-10-2009, 07:50 PM
My '99 A4 1.8T quattro tiptronic tranny went south. 4th & 5th were gone and the ECU or TCM would disengage the tranny in auto mode. So, on the advice of my mechanic, I did a swap. Now, in the mechanic's defense, this would have been relatively easy if we had a donor car. But we didn't and that was a big mistake. I piece-parted what I thought was needed from eBay, the local salvage yard, etc. And nothing went right. So, I'll summarize.

1. Crankshaft. The auto crankshaft does not have a pilot bearing for the input shaft to the manual tranny, so my mechanic took a V6 pilot bearing, cut it down, and made it fit. Be prepared to resolve the crankshaft incompatibility.

2. Tranny mount. The mount points on the subframe for an auto tranny are different than for a manual tranny. Be prepared to swap the subframe or cut and weld a new mount position on the driver's side.

3. Axles. The axles don't match from an auto to manual tranny. Be prepared to replace the front axles.

4. Rear differential. The final drive ratio for the auto and the manual are different. Be prepared to swap rear differentials or live with a mismatch and a lower top end speed.

5. Drive shaft/Propeller shaft. The drive shaft is not interchangeable. Be prepared to replace the drive shaft.

6. ECU. The ecu needs to be soft coded for a manual tranny. Actually, very easy with a vag-com. Be prepared to recode the ecu.

7. Safety interlock, backup light, other wiring. The safety interlock, etc., needs to be rewired. Be prepared to rewire.

8. Pedals, shiftbox, misc parts. Gotta source and replace the pedals, shiftbox, shifter boot, console pieces, etc. Be prepared to do it all.

Was it worth it? Considering my '99 is the best handling and best ride of all the A4s I've had, yes. However, it ain't cheap or easy and may not be for everyone.

SleeperAvant
03-29-2009, 08:14 AM
Informative post, thank-you.

BFlan2001
04-17-2009, 10:07 PM
my auto tranny feels like it's going to take a sh!t and i've been considering this....i think i'll still do it when the time comes..this post is a big help, thank you!

JettaRedII
04-18-2009, 03:51 AM
I should make another comment on the axles. I first tried a 2003 (B6 generation) transmission; I have a 1999.5 (B5 generation) engine. (I have a 1.8T AEB engine, so it may be different on a V6 or 2.7T.) But on the 1.8T, though the block had the same bolt pattern for the tranny, the axle flanges were different with the 2003 tranny and my axles (or any other axle set for a B5) would not match. 2003 axles would not fit a 1999 wheel hub. I finally had to find a tranny from another B5 generation car. In this case, a 2001.

So, also make sure you are at least working within the same generation for parts. That's another reason to have a matching donor car.