Tranny swap

texas325is · 10-22-2006, 01:32 PM

Ok, here is the situation, sorry for the long post. I have an 87 325is with an auto trans, I have access to an 87 318 manual trans with all linkage hook ups, upon visual inspection of the trans and where if mounts the block it looks similar, does anyone know if this will work and has anyone performed a trans swap from auto to manual? if so details please. Thanks for any and all advice.

Wayne 962 · Wayne 962's Garage

I get asked this question a lot. Yes, it's possible, but it's very involved, as you have to replace almost all of the equipment in the center tunnel, along with:

- Gear shifter
- Pedal cluster
- Master / Slave cylinder
- Transmission
- Sometimes flywheel
- Install tranny cooler

Etc, - the list goes on. I usually tell people it's easier to sell your car and buy a manual instead.

-Wayne

texas325is · 10-23-2006, 07:04 AM

Wayne,

Thank you for the info on this, I have another vehicle for driving and would like to eventually make this 325is a street/track car. I have looked around in my area for a 5-speed but so far have been unlucky, there are several in a junk yard close by so I thought I would just do the swap. aside from all the mechanical are there any electrical issues? I can get all the stuff from the donor car for $120.00 (another reason I am thinking about this. Thanks Chris

Wayne 962 · Wayne 962's Garage

There's a tranny computer that is hooked into the central system of the car. I'm not sure if simply removing it and the tranny will trigger any faults or codes - I haven't dont this myself.

If it's a track car that you're going to be gutting anyways, then I say go for it!

-Wayne

Lufeco · Lufeco's Garage

texas325is
I did such transplant 2 yrs. ago and couldn't be happier. But I got my parts from another 325, just like mine. I wouldn't know for sure if the tranny from a 318 will match the block on your 325.
Remember that you will also need another driveshaft (from donor car). Auto and 5-speed are different.
As far as electrical issues, you'll need to by-pass the connector switch that is attached to your auto shifter. Once you do this, there is a trick to keep your cruise control working, so my best advice is that you follow the electric diagram on the Bently book.
One more thing,,,, if your car is equipped with a 4.10 diff, after you do the transplant, you'll see that your car runs on high revs all the time, as if you needed a sixth gear. I got used to that, but I've seen people going to the more friendly 3.73 diff.
Good luck !!

texas325is · 11-25-2006, 10:23 AM

Hey thanks for the reply, I have recentloy come up with a new option, I found a '91 325i 5-speed and bought it, so now the '87 325is is becoming a donor car. then possible a dedicated racer.

Lufeco · Lufeco's Garage

texas325is
While you're at it, you should consider to instal a shifter either from a Z3 or an E36 M3. Both are a direct fit and will give you a shorter throw, much better than the original one.
I installed the M3 part on mine and love it. A friend of mine did the same just a day after driving my car and being able to feel the difference. BTW go ahead and replace all the bushings in/around the shifter as well.
I got the shifter from the dealership. I think I paid around $55-60, not bad considering some costing close to $400.00
Keep us posted on your progress.

texas325is · 11-28-2006, 05:41 AM

Yeah, I can't wait to do that, I am not at all happy with the OEM shifter and the long throw, I am currently going to replace the suspension at the moment it has given up the ghost, you know. over the weekend I replaced the interior from my 325is with the leather and ricaro seats so the interior is looking much better, as soon as I am done with a few other upgrades I'll post som pics. any other ideas that you've got please let me know.