Removal and installation the gearbox (BMW 3 Series E21)

Removal

Disconnect the wires from the battery terminals and, working from the engine compartment, unscrew the bolts securing the gearbox housing to the engine block.



Remove the exhaust pipe mounting brackets from the gearbox.

Disconnect the muffler inlet pipe from the exhaust manifold.

Disconnect the propeller shaft from the secondary shaft flange of the gearbox, leaving the flexible coupling on the end of the propeller shaft.

Loosen the nuts of the bolts securing the intermediate support crossmember to the body.

Release and remove the front propeller shaft.

Disconnect the speedometer flexible shaft from the speedometer drive. Depending on the gearbox modification, disconnect the wires from the reverse light switch on the rear cover of the gearbox housing.

Remove the wire bundle from the brackets on the gearbox and unscrew the bolts securing the gearbox to the suspension bracket.

Disconnect the gear shift rod by removing the retaining ring and washer from its end.

Remove the clutch slave cylinder by unscrewing the mounting nuts. Remove the clamp securing the clutch hydraulic drive feed line to the gearbox housing.



Remove the protective shield from the gearbox housing.

Disconnect the rear crossmember from the body, then unscrew the remaining mounting bolts.

Depending on the transmission modification, disconnect the wires from the reverse light switch located on the top of the gearbox.

Remove the gearbox.

Installation

Install the gearbox and tighten the accessible mounting bolts.

Attach the rear crossmember to the body.

Install the gearbox housing protective shield.

Install the clutch slave cylinder with the clutch hydraulic bleed screw facing down.

Secure the clutch drive feed line bracket to the gearbox housing.

Attach the shift rod, place a washer and a retaining ring on its pin.

Tighten the transmission mounting bolts to the suspension bracket and secure the wire harness to the transmission housing.

Connect the wires to the reverse light switch and connect the speedometer flexible shaft to the speedometer drive.

Install the front propeller shaft and tighten the nuts of the intermediate support crossmember mounting bolts to the body with a pre-tension of 2 mm in the direction of vehicle travel.

Attach the cardan shaft to the flange of the secondary shaft of the gearbox and tighten the nuts of the bolts securing the flexible coupling to the flange (the nuts must be replaced each time the drive shaft is removed).

Attach the exhaust pipe to the exhaust manifold.

Secure the exhaust pipe to the gearbox.

Loosen the nuts securing the muffler inlet pipe clamp.

Press the bracket against the exhaust pipe without applying excessive force and tighten the nuts of the bolts securing the exhaust pipe bracket to the gearbox and the nuts securing the exhaust pipe clamp.



Tighten the remaining transmission mounting bolts.

Connect the wires to the battery terminals.