Secondary shaft parts
9 - Front nut with longitudinal slot (or hexagonal); 10 - IV gear synchronizer locking ring; 11 - synchronizer with sliding ring for III and IV gears; 11a - synchronizer clutch of III and IV gears; 11b - synchronizer hub; 11c - synchronizer pressure springs; 11d - steel ball; 11th - cracker; 12 - III gear synchronizer locking ring; 13 - thrust washer III gear; 14 - third gear pinion; 15 - needle bearing III gear; 16 - secondary shaft; 18 - needle bearing 2nd gear; 19 - 2nd gear toothed wheel; 20 - thrust washer; 21 - 2nd gear synchronizer locking ring; 22 - synchronizer of 1st and 2nd gears with sliding clutch; 22a - sliding clutch of synchronizer of 1st and 2nd gears; 22b - synchronizer hub for 1st and 2nd gears; 22c - synchronizer pressure spring; 22d - steel ball; 22e - synchronizer cracker; 23 - 1st gear synchronizer locking ring; 24 - thrust washer; 25 - 1st gear bearing cage; 26 - 1st gear needle bearing; 27 - 1st gear toothed wheel; 28 - thrust washer; 29 - radial ball bearing; 30 - retaining ring; 31 - compensation washer; 32 - retaining ring of the secondary shaft rear bearing; 33 - locking plate; 34 - bolt; 35 - reverse gear toothed wheel; 45 - speedometer gear; 46 - secondary shaft flange; 47 - lock nut
Disassembly
1. Install the drive flange onto the rear end of the secondary shaft (temporarily) and secure it vertically in a vice.
2. Unscrew the nut from the front end and remove the synchronizer of III and IV gears and the locking ring.
3. Remove the 3rd gear thrust washer, 3rd gear gear and needle bearing.
4. Release the shaft from the vice and remove the thrust washer, 1st gear pinion and needle bearing rollers from the rear end.
5. Place the driven shaft in a vice so that the 2nd gear pinion is at the bottom, and use a soft metal hammer to lower it down so that the inner race of the 1st gear needle bearing is released.
6. Release the secondary shaft from the vice and remove the inner ring, thrust washer (if it exists), 1st gear synchronizer locking ring, 1st and 2nd gear synchronizer locking ring and 2nd gear synchronizer locking ring.
7. Remove the thrust washer (if it exists), 2nd gear pinion and needle bearing.
8. Wash all parts in solvent (kerosene) and perform defect detection. Pay attention to the presence of spiral (ring) springs and balls.
9. Place each synchronizer ring on its conical seat in the gear and measure with a feeler gauge between the gear teeth less than 0.5 mm, replace the synchronizer ring.
10. Disassemble the synchronizer. When disassembling a synchronizer with spiral springs, wrap it in a cloth, mark the position of the hub relative to the clutch, and then pull the hub out of the clutch. As soon as the hub comes out, the crackers, balls, and springs will shift (spring guides are provided on the 5th gear synchronizer). Replace the worn parts and assemble the synchronizer by placing the springs and keys in the hub. Then, holding the keys in the pressed position, partially insert the hub into the coupling. Place the balls one by one into the hub and, when all three are installed, push the hub completely into the coupling. Note that the synchronizing rings of the 1st and 2nd gears have a bevel on one corner. When installing, make sure that the bevel is facing the 2nd gear toothed wheel.
Synchronizer with ring springs
Synchronizer V gear with ring springs
Synchronizer with spiral springs
Publication taken from an online resource [MercedesMan.ru]
Synchronizer V gear with spiral springs
Checking the degree of wear of the synchronizer locking ring using a feeler gauge
Disassembling the synchronizer
1. To disassemble the synchronizer with ring springs, mark the position of the hub relative to the clutch, then remove the spring ring (only for V gear synchronizer), push the hub out of the clutch and pull out the crackers and springs. Replace the worn parts with new ones and reassemble the synchronizer, restoring the position of the hub relative to the clutch.
2. Note that the angled ends of the springs must be in the same cracker, and that the springs must face in opposite directions.
Assembly
1. Place the intermediate shaft vertically in a vice with soft (aluminum) with the jaws so that its rear end points upward. As you install the parts, lubricate them with clean gear grease.
2. Install the 2nd gear needle bearing onto the 2nd gear pinion and thrust washer (if it is provided).
3. Install the 2nd gear synchronizing ring onto the 2nd gear pinion and press the 1st and 2nd gear synchronizer unit onto the splines.
4. Install the 1st gear synchronizer ring on the synchronizer, install the thrust washer (if it is provided).
5. Heat the inner race of the 1st gear needle bearing and quickly press it into place on the driven shaft using a mandrel.
6. Install the needle bearing rollers, 1st gear pinion and thrust washer. Secure the 1st gear pinion and needle bearing in place with a piece of tubing and flange nut.
7. Turn the shaft over in a vice (the back end is pointing down) and secure it. Install the 3rd gear needle bearing and toothed thrust washer (if it is provided).
8. Install the 3rd gear synchronizer ring onto the 3rd gear pinion and press the 3rd and 4th gear synchronizer unit onto the splines, with the spline side of the clutch facing forward.
9. Screw the nut onto the front end of the driven shaft and tighten it to a torque of 8.0 kgf·m, fix the nut in the shaft groove.