How to Swap a Manual Tranny Into an Auto Tranny F-Body
By ButchN (firstname.lastname@example.org)
Many questions have been asked if a manual transmission can be installed into an A4 F-body. The answer is yes!
Parts you will need:
Some parts will need to be bought new (N) while others could be found in a wrecking yard or in a swap magazine or swap meet (S).
Invest $2 into a clutch alignment tool. Torque all bolts to proper settings.
First off, the tranny & bellhousing need to be from an F-body being there is a 45 degree offset in the way the tranny bolts to the bellhousing. This is probably for ground clearance, I don’t know.
Next step is to remove the distributor cap. You will be tilting the engine & the cap will break when it hits the firewall. I found out the hard way. The use of a tranny jack during the process will be helpful being the A4 trannys are heavy & awkward. I used a regular 2-ton floor jack being my tranny was junk & I did not care about damage. I removed my A4 in this order: driveshaft, (cap output shaft to prevent leakage), crossmember bolts, (the crossmembers were the same for A4 & M5, in my car anyway) tranny mount bolt, torque arm bolts at tranny only, (I found it not necessary to remove the entire torque arm).
Using the jack lower tranny to get to bellhousing bolts. The top 2 bolts after the tilt will require a long extension aproximately 18" with wobble to easily get to them. Remove shifter cable at tranny & downshift cable at TB. Remove feed & return lines at radiator & cap off. When tranny is out, do the same at tranny. Remove lockup & speedo wires or cable. Remove tranny.
If your starter is weak or on it’s way out, as mine was, now is the best time to replace it.
Install pilot bushing, flywheel, disc, pressure plate, using an alignment tool, align disc & tighten pressure plate, remove tool, install bellhousing with fork & release bearing.
For hydraulic clutches, install the slave to the bellhousing. The long extension will not be needed being you can now easily get to all 6 bellhousing bolts. Install transmission. It will be tight. This is because of the new pilot bushing. I put the tranny in gear & turned the output shaft to help the input shaft mate with splines on the disc.
When the tranny is seated, install the 4 retaining bolts. Jack tranny & mark center hump where the shifter will protrude. You will need to cut a hole here. I used the dimensions that I found in the boneyard cars, 6 1/4" X 7 1/2". The center console, E-brake arm, & shifter need to be removed at this point.
After the floor is cut, you can raise the tranny, install the mount bolt, torque arm bolts, crossmember bolts, & driveshaft. Install correct amount of tranny fluid. You will need to know if your tranny uses Dexron or gear oil. Install speedo wire or cable if so equipped. My car is a sensor & the tranny is a cable. I’m not sure which wires to jump on the lockup switch or if I need to. I’m in search of a sensor tailhousing for my speedo. I don’t know how the ECM reacts to it not being plugged in.
In the car you will need to remove the steering column to get to the brake pedal assy. You will need to cut your firewall wall to install the release mechanism. The master cylinder & power brake booster will need to be removed to aid in the install. Ifyou have the factory padding under the carpet, you will see the cutout for the clutch cable which will be a perfect template. If not, you will need to take the measurements from the car in which you removed the clutch assy. Remove the 4 bolts on the firewall which also aid in the removal of the vacuum booster & 1 bolt vertically above & infront of the brake pedal assy. Remove the entire assy & replace with the clutch pedal assy. It is important to note here that if your existing pedal assy, such as mine was, does not have the provision for the extra pedal, or if you are not sure, it would be wise while at the boneyard to just get the entire assy. That way you will not have to worry about not having the parts needed to complete the job. Install brake booster, master cylinder, clutch pedal assy, clutch cable, brake arm, neutral safety switch, stoplight switch & cruise disengage switch if so equipped.
To install shifter, you will need to remove the center console, brake lever & shifter. I removed my ignition key lock cable from the ignition switch & discarded it. I found the clutch neutral switch wires taped up under my dash which made life easy so the clutch has to be depressed to start car. It is a purple/yellow pair. For the shifter, install it to the tranny, find which wires activate your reverse lights & wire them to the connector on the side of your tranny so they will come on when you shift into reverse.
Install lower boot, E-brake arm, console & upper shifter console.
You’re done! If you have a hydraulic clutch, it is self adjusting, for a manual "Z" bar, you need to adjust it before you can drive. Proper adjustment is the clutch engaging about 1 1/2" from floor with no pressure on pedal when it is fully released. This is so the release bearing has no undue stress on pressure plate fingers.
Clean up, drive away, have fun!
This was the 1st time I did this & I spent 11 man-hours spread out over 2 days. I have 2:73’s and noticed a decrease in my off-the-line performance but my all around was a much more noticeable, more "drivable" improvement. My next step is gears, probably 3:23 or 3:42’s. That’s all I can think of.