Removal and Replacement

Removing and Installing Front Transmission Cover and Primary Pump

Preceding work:
Removing and installing transmission with torque converter. Remove and Installing Transmission With Torque Converter







Remove, install Front transmission cover (10) by unscrewing, screwing in bolts (18), 13 Nm, check gasket (19).

Take off, insert, Teflon rings (9), stick in place with grease, joint of rings must stay together.

Remove and insert Snap ring (15) by tensioning spring plate (13) using assembly device.

Take off, fit on, Spring plate (13) and return springs (14).

Pull out, Piston (12), check lip seals (16, 17), replace if necessary.
Remove and install, Primary pump (1-4) by loosening bolts (8), 20 Nm. Pull out pump gears (3, 4), insert and check. chamfer of primary pump gear (4) must be facing bearing bush in primary pump housing cover.

Check, replace, Radial seals (6) and O-ring (7) if necessary, and also check radial roller bearing in primary pump housing cover.



Special Tools











Return spring for B3 piston






Removal and Installation

1. Pull off front cover (10) by screwing two bolts into the tapped holes (arrows).






Note:
Do not use the two bolts to press off cover (10). If necessary, loosen cover using a screwdriver.


Installation Note
Clean sealing face of front transmission cover, check gasket for signs of damage and replace if necessary. As a rule, the gasket can be used several times. It must not be coated with sealant.
Coat bolts with non-hardening sealant and tighten to 13 Nm.


2. Take off the two Teflon rings (9).






Installation Note:
Insert Teflon rings (9) with grease.
Ensure that joint of rings (arrow) stays together.
If necessary remove rings again and shape them to a smaller diameter.






3. Mount assembly device (020) onto the spring plate (13) and tension until snap ring (15) is exposed. Take out snap ring, release tension on assembly device and remove.

Installation Note
Mount assembly device (020) onto the spring plate and tension. Insert snap ring (15). Release tension on assembly device and remove.

4. Take off spring plate (13) and return spring (14) for pistons B3.






Installation Note
Number of return springs 20.


Note:
From transmission no. 25 794 up to approx. transmission no. 31 000, only 5 return springs were installed. When performing repairs, install 20 return springs in the front cover together with green ball valve.

The upper part of the stator shaft (15) must lie absolutely flat on the bush (16) (arrow).






5. Pull out piston (12).

Installation Note
check lip seals (16, 17) and replace if necessary. Lip seals must be installed in such a way that sealing lip is facing downwards (direction of arrow).






Fit insertion sleeve (024) onto front cover (10). Lubricate sliding surfaces for lip seals.

Lubricate lip seals at piston. Insert piston (12) in such a way that the stud (on piston) and the hole (1n front cover) are aligned. Press down piston carefully without tilting it; if necessary, move it down by pressing a pin against the outer lip seal (arrow). Take off insertion sleeve (024).






6. Loosen bolts (8) and unscrew.

7. Remove primary pump from front cover.

Installation Note
Insert M8 x 32 bolts (8) and tighten to 20 Nm.






Note:
Check that ball valve (23) is properly seated. When performing repairs on transmissions with a lower transmissions end no. than 316 257, the retaining plate (24) must also be installed.
In transmissions with a Belleville spring washer in B3 multi-disc brake, the ball valve is not fitted.






8. Remove both pump gears (3, 4) from pump housing.

Installation Note
Oil both pump gears (3, 4) and place in pump housing. Insert pump gear (4) in such a way that chamfer (arrow) is facing the radial roller bearing (20).

If the radial roller bearing (20) is damaged, the primary pump must be replaced.






9. Check radial seal (6) and replace if necessary.

10. Replace O-ring (7). Insert O-ring into the groove, ensuring that it is not twisted.