Dynashift removing and install

Split the tractor between the engine and gearbox.
Drain the gearbox.
Remove the selector cover.
Remove the reverse shuttle selector.
Remove the clutch assembly.
Remove the direct drive shaft.
Remove the clutch control valve as well as the transfer tubes connected to the unit (lube and 17-bar pressure).
Remove the input unit and place on a work bench in the vertical position.


Removing and disassembly the cover, housing, front clutch and brake

Using two locally manufactured lugs or rings, remove the assembly comprising shaft (7), cover (13) and housing (21).

Retrieve stop (70). Compress spring washer (77) by pressing on ring gear (31). Remove circlip (69) and withdraw shaft (7). Withdraw piston (37) from housing (21).
Lock ring gear (34). Remove screws (25).

Extract the assembly comprising ring gear (34), crown wheel carrier (1), ring gear (31) and bearing. Separate ring gear (34) from crown wheel carrier (1). Remove spring washer (77) and bearing (27).
Remove housing (21) and piston (22).
Remove discs (3) and (15), intermediate plates (2), and clutch plate (17), drive hub (5), springs (20) and thrust plate (16). Extract cup washer (4) and unit (14).

Removing and separating the planet  pinion cage assembly

Compress the planet pinion cage assembly.
Remove ring (72). Remove stud washer (76), the planet pinion cage assembly and shims (71) installed against the front and rear faces of planet pinion cage (28).
Remove secondary sun gear (61) and retaining ring (49) (if necessary).
Remove circlip (55). Remove bearing (57) and spacer (56).
Separate secondary planet-pinion cage (39) from primary planet-pinion cage (28).
Remove retaining ring (60) and bearing (58).
Set the secondary planet-pinion cage in the vertical position. Tap the cage lightly on a wooden block in order to extract needles (63). Separate the planet pinion cage from primary sun gear (64), complete with ring (62) and oil splasher (75).

Disassembling the rear clutch and brake

Remove clutch plate (38), springs (65), discs (41) separated from clutch plate (44).
Remove the assembly comprising housing (59), thrust plate (45) and last disc (41). Remove friction washer (51).
Remove screws (46). Remove cover (47) and cup washers (52). Separate thrust plate (45), discs (50) and intermediate plates (48). Remove drive hub (54). Remove screws (43). Unstick and remove unit (42) take care to mark its position.

Assembling the planet pinion cages

Clean and check the parts, replacing any that are faulty.
Ensure that the lube ports in the planet pinion cage shafts are not blocked.
Manually check the axial play and rotation of each sun gear.
Install primary sun gear (64) fitted with ring (62) and oil splasher (75), in secondary planet-pinion cage (39). Insert three needles (63) through holes in primary sun gear, so that they abut on bottom of groove in secondary planet-pinion cage.

Install bearing (58), install ring (60).
Assemble the secondary planet-pinion cage on primary planet-pinion cage (28). Turn the sun gears in order to facilitate meshing.
Install spacer (56) and bearing (57); install circlip (55).
Check manually for normal backlash between the primary sun gears.
Install ring (49) (if it was removed) on secondary sun gear (61).

Reassembling the rear clutch and brake

Clean and check the parts, replacing any that are faulty.
Blast compressed air into the tube of the reverse drive idling gear to ensure it is not blocked.
Coat the mating face of unit (42) with sealing compound around the lube line and install. Coat screw (43) with Loctite 241, install and torque to 31-35 Nm.
To access screws (46), turn the planet pinion cage upside down. Install secondary sun gear (61), housing (59) and hub (54), the inside splines facing downwards.

Install discs (50), intermediate plates (48), thrust plate (45) and cup washers (52) per Fig. 1, and cover (47).

Centre housing assembly (59). Coat screws (46) with Loctite 241 and torque to 13 - 15 Nm. Remove the tool. Separate the housing assembly from the planet pinion cage.      

Coat washer (51) with miscible grease and apply to cover (47). Install one disc (41) inside unit (42). Place housing assembly (59) and washer (51) on shaft (53). Install drive hub (54), the inside splines facing upwards. Install the other two discs (41), separated by clutch plate (44).

Reassembling the cover, front clutch, brake and housing

If replacement of front cover (13) proves to be necessary, degrease washer (79) and its mating face on the cover. Lightly smear one face of this washer with Loctite 648 or similar then stick on the cover. Leave to dry for a few moments.
Ensure presence of rivets on cover. Place the cover on a suitable support. Check for presence of washer (79). Coat friction washer (10) with miscible grease and apply to housing (14). Install transmission shaft (7) and housing. Position cup washer (4), fit one disc (15) and thrust plate (16).

Fit drive hub (5) with internal splines facing upwards on transmission shaft (7). Install discs (3) and intermediate plates (2).

Install the other two discs (15), separated by clutch plate (17).
Install springs (20). Fit O’ring (73).
Ensure presence of rivets (23) and (29). Ensure that the pipes to pistons (22) and (37) in housing (21) are not blocked.
Lubricate seals (24) and (26) and install respectively on piston (22) and inside housing (21).
Position the piston in the housing and fit using a plastic hammer to tap progressively and alternately around the edge.
Screw two guide studs into housing (21) and position on cover (13). Check that the lube pipe in the housing corresponds to the one on the cover.

Replacing cover (13) on housing (21) or reverse-shuttle housing (40) requires checking and if necessary readjusting the clutch.
Remove the guide studs. Coat screw (18) with Loctite 241, install, and torque to 29 - 37 Nm.

Leak tightness test of piston (22)
- Connect a pressure gauge fitted with a sealed valve and a suitable fixture on the port of the front piston. Ensure piston and seals are correctly seated by pressurizing the system several times to two or three bar, then feed the circuit with compressed air at 0.3 bar. Close the valve and check that no pressure drop occurs for one minute.
Install bearing (27) on ring gear (31) and place inside crown-wheel carrier (1) together with spring washer (77). Install ring gear (34). Apply Loctite 241 to screws (33), install the screws and torque to 13 - 15 Nm. Fit the crown-wheel assemblies onto transmission shaft (7). Lock ring gear (34). Apply Loctite 241 to screws (25) and torque to 31 - 35 Nm.
Compress spring washer (77) by pressing ring gear (31). Install circlip (69). Coat stop (70) with miscible grease and install.

Lubricate and install seals (35) and (36). Position the piston in the housing and fit by tapping progressively around the edges with a plastic hammer.

Leak tightness test of piston (37)
- Maintain the piston using a suitable fixture. Check sealing of the joints, as for the front piston.

Shimming  the planet  pinion cage

Adjusting clearance 

For adjusting clearances J1 and J2, springs (65) and clutch plate (38) must be removed.

Operations on rear clutch housing :
Use a depth gauge to measure dimensions b and c at two opposing points. Take the average of the two readings. Calculate dimension: A = b - c

Operations on the planet pinion cage assembly 
Install secondary sun gear (61) complete with retaining ring (49) on ball bearing (57).
Measure dimension D using a depth gauge.

Determine gap E between primary planet-pinion cage (28) and hub (54) according to the formula: E = A + D
Fill space E with shims (71) having a value of E +0.50 mini to + 0.70 maxi, to give a clearance of : J1 = E + 0.50 to 0.70 mm

Adjusting clearance 
Place sun gear (61) on housing (59) and the planet pinion cage assembly on shaft (53). Install washer (76) and ring (72).
Position the feeler of a dial gauge and check the clearance by moving the planet pinion cage assembly vertically.
Depending on the measured clearance, select the thickness of shims (71) to obtain J2 = 0 / 0.20 mm.

Remove the planet pinion cage assembly
Install springs (65). Position clutch plate (38), ensuring that the notches align with the tabs of unit (42).
Ensure presence of shims (71) defined at operation 68.
Install sun gear (61) and the planet pinion cage assembly, and compress the parts.
Set shims (71) selected at operation 71 against planet pinion cage (28). Install washer (76) and ring (72). Check manually for normal backlash between the secondary sun gears.

Assembling  the  input  unit

Install new O’rings (32) and (68) on reverse shuttle housing (40). Screw in two guide studs at opposing locations.
Use a sling to reinstall the assembly comprising transmission shaft (7), cover (13) and housing (21), ensuring the lube pipe is aligned.
Rotate the shaft in order to mesh the sun gears in the ring gears.
Remove the guide studs. Install screws (30) and torque to 72 - 96 Nm.
Check for proper rotation of the shaft. Install the input unit and the PTO drive line. Reassemble the front clutch. Install the reverse shuttle. Install the selector cover.

Reassemble the tractor between the engine and gearbox.
Service the oil in the sumps and check the level in the sight glass located on the left of the center housing.
Bleed the clutch control if necessary.
Proceed to road-test of all Dynashift controls and gear ranges A, B, C and D. Check for leak tightness at couplings and mating face of selector cover.