My Tranny Swap
 

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.

i guess that is good general information. it would be better if you gave specifics to what you did. for instance

#4- did you swap rear differentials? where did you get it from, what vehicle/part number was it?

#6- what was the specific coding in vag com that you had to do?

#8- how did you rig up the clutch, master and slave cyl? was the pedal bolt on or did you have to rig up a mount for it?

Good points. I will try to provide more info.

#4- did you swap rear differentials? where did you get it from, what vehicle/part number was it?

I've ordered a new diff, but haven't received it yet. The auto diff is coded DAK (01H500040K) with a 37:9 final ratio and the manual diff is coded DAJ (01H500040J) with a 35:9 final ratio. I've ordered the diff from eBay and hope the rear axles fit! I'll post a follow up.

#6- what was the specific coding in vag com that you had to do?

I don't have a VAG-COM in front of me, but if you go to 01-Engine, Coding-07, and run your cursor over the Soft Coding text, it'll show you what the values mean. Here's an example.

#8- how did you rig up the clutch, master and slave cyl? was the pedal bolt on or did you have to rig up a mount for it?

My mechanic did all this stuff. But I think he just added the cylinders and hooked them to the clutch. Can't explain any more than that. The pedals were a direct bolt on, thought there was a $5.49 plastic clip that we needed to get.

I wish there was more I knew to tell you, but generally there are a lot of "little things" that make it tough if you don't have a donor car.