Mainshaft: Service and Repair

Subassembly Operations

NOTE: The following subassembly operations are the same for both 4x2 and 4x4 models.






Mainshaft Disassembly






1. Remove the selective snap ring that retains the 3-4 synchronizer assembly to the mainshaft. A new snap ring will be used in the assembly.






2. Remove the 3-4 synchronizer assembly (hub, sleeve, spring and keys), synchronizer ring, third speed gear and caged needle bearing from the front of the mainshaft. Note the position of the synchronizer hub and sleeve during disassembly.






3. Position the mainshaft assembly in a press so the second speed gear is supported by the press bed. Press the mainshaft down and out from the 1-2 gear assembly.






4. Separate the inner ball bearing, bearing sleeve, first speed gear, caged needle bearing, 1-2 synchronizer assembly (hub, sleeve two springs and three keys), second speed gear and caged needle bearing. Note the direction of 1-2 synchronizer hub and sleeve during disassembly. Discard the inner ball bearing.

Assembly

NOTE: Prior to assembly, lubricate all components with Standard Transmission Lubricant (SAE 80W), D8DZ-19C547-A (ESP-M2C83-C) or equivalent.






1. Check the clearance between the synchronizer rings and gears. Install the ring on the gear and insert a feeler gauge between the ring teeth and gear. If the clearance is less than 0.23 mm (0.009 inch), replace the ring and/or gear.
2. From the rear of the mainshaft, install the caged needle bearing for the second speed gear.
3. Position the second speed gear on the mainshaft with the synchronizer ring surface facing the rear of the shaft.
4. Install the synchronizer ring on the second speed gear.
5. Position the 1-2 synchronizer assembly on the rear of the mainshaft, making sure that:
a. The splines of the mainshaft and synchronizer are properly aligned.






b. The rear of the 1-2 hub is identified by a ridge machined on the rear surface. The ridge must face the front of the mainshaft.






c. The small bevel angle of the sleeve faces the front of the mainshaft.
d. The synchronizer sleeve has a tooth missing at six positions. Assemble the hub to the sleeve so the single tooth between the two missing portions will touch the synchronizer key.






e. The synchronizer keys and springs are properly installed. The open ends of the spring do not face each other.






6. Press the 1-2 synchronizer assembly in position on the mainshaft using Replacing Shaft Sleeve, T75L-7025-K, Shaft Collar, T75L-7025-M and Tube, T75L-7025-C or equivalent. If properly installed, the second speed gear should rotate freely.






7. Position the first gear bearing sleeve on the mainshaft. Press the sleeve on the shaft using Replacing Shaft Sleeve, T75L7O25-K, Shaft Collar, T75L-7025-M, Rack Bushing Holder, T81P-35O4-D (or an appropriate washer) and Tube, T75L-7025-C. When properly installed, the sleeve should be against the synchronizer hub. Make sure the gears rotate freely.






8. Install the synchronizer ring on the 1-2 synchronizer assembly
9. Install the caged needle bearing and first speed gear.






10. Slide the inner ball bearing in position on the mainshaft.
11. Press the inner ball bearing on the mainshaft using Rack Bushing Holder, T81P-3504-D (or an appropriate size washer), Tube, T85T-7025-A, Replacing Shaft Sleeve, T75L-7025-K, and Shaft Collar, T75L-7025-M. When properly installed, the gears should rotate freely.






12. Install the third speed gear and caged needle bearing over the front of the mainshaft.
13. Install the synchronizer ring against the third speed gear.






14. Make sure the 3-4 synchronizer assembly is properly installed. Be sure that:
a. The splines of the mainshaft and synchronizer are properly aligned.
b. The small diameter boss of the hub faces the front of the mainshaft.






c. The small bevel angle of the sleeve faces the front of the mainshaft.






d. The synchronizer sleeve has a tooth missing at six positions. Assemble the hub to the sleeve so the single tooth between the two missing portions will touch the synchronizer key.
e. The synchronizer springs and keys are properly installed. The open ends of each spring do not face each other.






15. Install the 3-4 synchronizer assembly on the front of the mainshaft.






16. Install a new selective snap ring that retains the 3-4 synchronizer assembly to the mainshaft. Select the thickest snap ring that fits in the groove. Refer to the Mainshaft Selective Snap Ring Chart in the Specifications portion of this Section for available sizes and identification colors of the snap rings.