Manual Transmission
(4SP) Conversion

By Gunter (aka: Ben Nesbitt)

The Author makes no claims as to the eventual success of this operation, and assumes no liability for damages and/or injury incured during said op. The nature of this procedure assumes a fair amount of experience and the knowledge of certain safety considerations that must be followed.

If you want to whine to him about something awful that happened, he will merely chuckle, nod his head and say: "Yup. that happened to me too."

Parts required:
  • One running bavaria with worn-out stupid and worthless automatic transmission.
  • Ideally, another bavaria of comparable model-year with a complete manual drive train.
  • Four jackstands.
  • A large floorjack - two are even better.
  • A very willing and unquestioning buddy.
If you aren't in a position to keep a complete parts car, here is a list of what you  will need to take home from the manual donnor car:
  • 4sp trans. with good clutch and driveplate.
  • The transmission support crossmember (bushings are same)
  • The foreward section of the driveshaft (for the sake of balance,  just take the whole thing)
  • The pedal assemmbly (both, as the manual brake pedal is smaller)  
  • Clutch slave cylinder.
  • Clutch master cylinder (don't forget the hose).
  • The brake/clutch fluid resevior - it has an extra outlet.  
  • OPTIONAL - radiator - it lacks the trans. fluid in/outlets. interior parts to accomodate the new shift lever.
  • Reverse light wiring harness (almost forgot)


Ok, the adventure begins: NOTE: Your freindly and informative Haynes or Chilton book will tell you how to remove  most of the major components. Do it like they say and you can't go too far wrong, but I have included some procedures that are not well explained in the books.
It goes like this:


On the Auto Car
  Remove the exhaust at the downpipe/manifold connection
  Remove the driveshaft
  Remove the shift lever and unhook all of the wires going to the trans.    (speedo cable, too)
  Remove the transmission drain plug and drain the fluid - this is not easy if you have a BW as it is a large, flat head type bolt. It may be better to unscrew the fluid pipes that go to the radiator and plug the holes with chewing gum or soft wax. Fluid will probably go everywhere anyway. Keep a pan and some BIG rags handy.
  Support the trans. with a jack and remove the trans. cross member.
  Remove all of the bellhousing to engine bolts that you can see from under the car.
  Now lower the jack until the trans. is resting on the front frame cross member.
  Remove the bellhousing to engine bolts that you couldn't see before from under the hood IMPORTANT - leave one bolt in - one that is easily accessable when the transmission is raised back up.
  Support the trans. with a jack at each end or one in the center and a strong buddy under the car, BEHIND THE TRANS - either way, use a buddy to stabilize it.
  Raise the trans a bit to release strain between it and the engine
  Undo the last bolt and pry the trans away with a really big screw driver while your happless buddy pulls it backward (be ready for the torque converter to fall on your leg and drench it with fluid) - YEEEHAAAWWW! - it's out.
  Throw the stupid thing away
  Remove those darn fluid circulation pipes from the raditor. If you feel like it, now is a a good time to put in the new radiator.
  Remove the foot pedal/s by undoing the big bolts on the ends of the shaft on which it hangs. You'll need to remove the pressboard/vinyl console cover thingee first. While you're down there, pop out the two plastic plugs that fill the holes where the bolts for the clutch master cyinder go.
  Remove the brake/clutch fluid resevoir (save the bolt)


On The Manual Donor Car:

  Repeat steps 1-15 (omit steps 12 and 13  =8^] ) Don't forget to remove the clutch slave cylinder when you take out the trans. You can leave the crossmember attached.
  Remove the clutch master cylinder


Back to the Nice, Formerly Automatic Car

  Install the fluid resevoir, master cylinder and foot pedals - it's all pretty self explanatory when you get there. Did you flush the fluid? You didn't did you.You're a pretty lame excuse for a mechanic.
  Ok, sorry about #18, I got carried away. It's time for a beer break.
  Drink beer.
  Stop drinking beer.
  Now, it's time to sort out the pilot bearing situation; if you had a Borg Warner automatic, there will be no bearing inside the end of the crankshaft. The ZF has one - pull it out (I don't know HOW - I had the BW). Now go to BMW and get a new pilot bearing for a manual trans - depends on the model. Put it in. (GREASE!)
  Using the same jack/buddy combination as before, wrestle the manual trans. into the tunnel. Did you sort out the clutch and throwout bearing? Do up all the bolts.
  Put in the new driveshaft. It helps if you have a LARGE hose clamp to squash the guibo down so the bolts will go in (careful, don't abuse it. An abused guibo grows up to be a bad, violent guibo with sociopathic tendencies).
  Ok, so, here's the electrical part. Remember the big wire glob and plastic connector that came off the auto and is now hanging from the firewall?  Cut it (or save it for posterity - I don't care). Don't cut off the small plug that goes to the reverse light wiring harness. Oh, yeah, get the reverse light wiring harness off of the donnor car. Hook it up.
  Now this part is cool.The auto cars have an extra starting solenoid that we have to bypass now or the car will never turn over. On the passenger side of the coolant tank, on top of the brake booster is the solenoid. In addition to the other crap going into it, there should be a single black wire going in. Unhook this wire. Now, mounted right on top of the brake booster is a plastic plug with two wires coming out the driver side, and one coming out the passenger side. Plug the black wire (it should have a flat tang on it) into the plug on the passenger side where there was no wire before.
  If step 27 did not work for you, refer to the electric schematic for your vehical. I figured it out and I've never read a schematic before so it can't be too tough. 29 Are you exited yet?  Unless I forgot something, you can put the shift lever in now and fire the sucker up.
  Once the engine has warmed up, depress the clutch and rev the engine to about 5500 rpm. Quickly release the clutch pedal.

Wasn't that cool?


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