Subject: E30 transmission guide
To: dale

Firstly, all 'i' motors use a crank position sensor on the front of the crank, all 'eta' motors (super-eta may be an exception) use the 2 reference sensors mounted in the trans bellhousing.

There are a couple of issues using an '86 325e manual transmission in an '89 325i car.

Identify which trans you have early 'eta', late 'eta', or 'i':

  1. early 'eta' trans (1983, 1984, 1985 manufacture dates?)
    1. 260.0.1270.90 is on the side of the 'eta' trans
    2. shifter mounting about the output flange is only 2xM10 holes for the 84,85,86 style plate mount shifter
    3. deep bellhousing : Slave cylinder mounting flange = 6 7/8
    4. 2 drilled holes for crank position sensors
    5. smaller output flange

    b) late 'eta' trans (1986, 1987, 1988 manufacture dates?)

    1. 260.0.1270.90 is on the side of the 'eta' trans
    2. shifter mounting about the output flange has 2xM10 holes for the 84,85,86 style plate mount shifter, AND top boss for the aluminum bracket of the 87-91 style shifting mechanism.
    3. shallow bellhousing : Slave cylinder mounting flange = 6 1/2
    4. cast boss for 2 drilled holes for crank position sensors, may or may not be drilled
    5. larger output flange

    c) 'i' trans

    1. 260.0.1346.90 is on the side of the 'i' trans
    2. top boss for the aluminum bracket of the 87-91 style shifting mechanism.
    3. shallow bellhousing : Slave cylinder mounting flange = 6 1/2
    4. no cast boss in bellhousing for reference sensors
    5. smaller output flange

If you find your 'eta' 260 trans has the deeper bellhousing, you can correct for it by using a thicker throw-out bearing. Sachs P/N 21511204525 is a 30mm bearing and will make up the difference.

If you use the driveshaft/guibo that came with the transmission you'll be fine, the differential end of the driveshaft is the same on all the 6cyl E30s.