New Synchromesh Mechanism For 4-Speed and 5-Speed Gearboxes

The cone angles of the synchromesh sleeve and baulk ring have been altered from 6.67° to 6°. In addition, the baulk rings for 2nd and 3rd gears are coated with molybdenum. The gearwheels have asymmetrical tooth tip angles.
All new parts have been introduced on 5-speed gearboxes as from gearbox numbers 523814 and 480053. On 4-speed gearboxes, a new gearwheel for 2nd gear has been introduced as from gearbox No. 174284.

MARKING
To prevent mix-ups between new and old parts, the new baulk rings are provided with 6 pads (in pairs) on the outside diameter and the new sleeves have a turned step on the periphery. The step can face either towards the front or towards the rear. The difference between old and new gearwheels is very clear, since the new gearwheels have asymmetrically bevelled dog teeth.

NOTE: The new synchromesh sleeve (87 20 419) must always be matched with two baulk rings of the new design (87 19 916 and 87 19 924) and vice versa.





1. Turned step (can face either towards the front or towards the rear)
2. Cone angle
3. Synchromesh sleeve
4. Baulk ring
5. Gearwheel
6. Symmetrical
7. Tip angle
8. Asymmetrical





BAULK RING 87 19 916 (MOLYBDENUM-COATED)
1. Pads (3 pairs) showing that the baulk ring has a cone angle of 6°

BAULK RING 87 19 924
1. Pads (3 pairs) indicate a cone angle of 6°