Part 1 of 2
ASSEMBLYNOTE: Gaskets are not used in the NV4500 transmission. Use Mopar1 Silicone Sealer or equivalent on all gear case and extension housing sealing surfaces.
COUNTERSHAFT AND REVERSE IDLER GEAR
1. Install countershaft front bearing cup in case with Handle C-4171 and Installer 6061-1.2
2. Install front bearing on countershaft with Installer C-4340 (Fig. 64).
3. Lubricate countershaft front bearing cup and cone with petroleum jelly.
4. Position gear case on end with rear of case facing up (Fig. 65).
5. Install countershaft in gear case (Fig. 65).
NOTE: Do not install rear countershaft bearing on countershaft at this time.
6. Lubricate reverse idler gear bearings with petroleum jelly and install first bearing and second bearing (Fig. 66).
7. Install idler gear front thrust washer on boss in gear case (Fig. 66). Coat thrust washer with liberal quantity of petroleum jelly to hold it in place.
8. Install reverse idler gear in case (Fig. 67).
9. Install idler gear rear thrust washer between idler gear and case boss (Fig. 67).
10. Align idler gear bearings and thrust washers with a drift.
11. Install reverse idler shaft with notched end of shaft facing countershaft (Fig. 68).
12. Lift countershaft upward and position wood block between front of shaft and case (Fig. 69).
13. Install rear bearing cone on countershaft with Installer C-4040 (Fig. 70).
14. Remove wood block from under countershaft and lower countershaft front bearing into front bearing cup.
15. Lubricate countershaft rear bearing cup and cone with petroleum jelly.
16. Install countershaft rear bearing cup in gear case and over rear bearing (Fig. 71). Tap cup into place with plastic mallet if necessary.
17. Install countershaft rear bearing plate (Fig. 72).
NOTE: Verify plate is seated in notch in reverse Idler shaft before tightening bearing plate bolts.
18. Apply Mopar silicone adhesive/sealer to flange and lip of new cap. Install new front bearing cap in gear case (Fig. 73) with Handle C-4171 and Installer C-3972-A.
COUNTERSHAFT END PLAY
1. Rotate countershaft 4-5 times to seat bearings.
2. Mount dial indicator on case. Then position indicator plunger on end of countershaft and zero dial indicator (Fig. 74).
3. Raise countershaft with screwdriver and note end play reading on dial indicator. End play should be 0.051 - 0.15 mm (0.002 - 0.006 inch).
4. Remove countershaft rear bearing plate.
5. Install a end play shim that will provide minimum countershaft, end play. Position shim on rear bearing cup (Fig. 75).
6. Install countershaft rear bearing plate (Fig. 72).
NOTE: Verify plate is seated in reverse idler shaft notch and end play shims are still in position before installing bolts.
7. Apply 1-2 drops Mopar Loc N' Seal or equivalent to threads of rear bearing plate bolts. Then install and tighten bearing plate bolts to 23 Nm (200 inch lbs.).
SHIFT LUG AND RAIL
1. Lubricate shift lug and rail with Castrol Syntorq.
2. Insert shift lug rail part way into case.
3. Install shift lug on rail.
4. Position shift rail so roll pin notches are toward outside of case (Fig. 76).
5. Install roll pin that secures lug to rail (Fig. 76).
MAINSHAFT AND GEARTRAIN
CAUTION: The reverse, 1-2 and 3-4 synchro components can be assembled and installed incorrectly. Follow assembly procedures for component identification and location.
Lubricate mainshaft bearing surfaces and all bearing assemblies with Castrol Syntorq or with petroleum jelly.
1. Install first snap ring in rear most groove of mainshaft hub (Fig. 77). This snap ring locates first gear clutch gear on shaft.
NOTE: Four of these snap rings are used to secure various components on the mainshaft 1-2 synchro hub. The snap rings are all the same size and are interchangeable.
2. Install first gear clutch cone on mainshaft 1-2 synchro hub with recessed side of cone facing front (Fig. 78). Verify cone is seated against snap ring on hub.
3. Install snap ring on mainshaft 1-2 synchro hub to secure clutch cone (Fig. 79). Verify snap ring is seated in hub groove and against clutch cone.
4. Support mainshaft in upright position to install remaining gears, snap rings and synchro components. Shaft can be supported in gear case or hole can be cut in workbench to support shaft.
5. If 1-2 synchro hub and sleeve were disassembled for service, reassemble hub, sleeve, struts and springs as follows:
a. Align and install sleeve on hub. Rotate sleeve until it slides onto hub. Sleeve only fits one way and will easily slide onto hub when long slot in sleeve, aligns with long shoulder on hub (Fig. 80).
b. Place wood blocks under hub that will raise hub, about 3.5 cm (1.375 inch) above surface of workbench. Then allow sleeve to drop down on hub (Fig. 81).
c. Install springs and struts in hub (Fig. 81). Use lots of petroleum jelly to hold them in place. Then compress struts with your fingers and move sleeve upward until struts are started in sleeve. Verify that struts are engaged in sleeve before proceeding.
d. Turn synchro assembly upright. Then move sleeve into neutral position on hub and work struts into sleeve at same time. Be sure struts are seated and springs are not displaced during assembly.
6. Install first gear stop ring in 1-2 synchro hub and sleeve (Fig. 82). Verify stop ring is seated and engaged in hub and sleeve.
7. Install 1-2 synchro assembly and stop ring on mainshaft with the taper on the sleeve facing forward. (Fig. 83).
8. Install snap ring that secures 1-2 synchro on mainshaft hub (Fig. 84). Verify snap ring is seated in groove in mainshaft hub.
9. Assemble second gear clutch cone, clutch ring and stop ring (Fig. 85).
10. Install assembled second gear clutch cone and rings on mainshaft and in 1-2 synchro hub (Fig. 86).
11. Install snap ring that secures second gear clutch cone on mainshaft (Fig. 87). Use narrow blade screwdriver to work snap ring into hub groove as shown. Verify snap ring is seated in mainshaft groove.
NOTE: If snap ring will not fit in groove, clutch cone is slightly misaligned.
12. Install second gear bearing on mainshaft (Fig. 88).
13. Install second gear on mainshaft and bearing. Rotate gear until tabs of second gear clutch ring are seated in tab slots in gear (Fig. 89).
14. Install thrust washer pin in shaft (Fig. 90).
15. Install second gear thrust washer. Verify washer is seated on gear and pin (Fig. 91).
16. Install second gear thrust washer snap ring (Fig. 92). Verify snap ring is seated in mainshaft groove.
17. Install third gear bearing spacer on shaft and seat it against thrust washer snap ring (Fig. 92).
18. Install third gear bearing on mainshaft (Fig. 93). Bearing should be flush with mainshaft hub.
NOTE: If bearing is not flush with hub, the bearing spacer or snap ring was not installed.
19. Install third gear over bearing and onto mainshaft (Fig. 94).
20. Install synchro stop ring on third gear (Fig. 95). Verify stop ring is seated on cone taper.
21. If 3-4 synchro was disassembled for service, reassemble synchro components as follows:
a. Align and install synchro sleeve on hub (Fig. 96). Front side of hub has a narrow groove machined in it.
b. Insert all three synchro struts in slots machined in sleeve and hub (Fig. 96).
c. Install and seat synchro springs (Fig. 96).
Use flat blade or Phillips screwdriver to compress springs and seat them in struts and hub as shown.
22. Start 3-4 synchro assembly on mainshaft with the hub groove and sleeve groove both facing forward. Tap assembly onto shaft splines until hub is about 3 mm (0.125 inch) away from third gear stop ring. Then align stop ring with synchro sleeve and hub and seat synchro assembly with Installer C-4040 (Fig. 97).
23. Verify 3-4 synchro hub is seated on shaft with approximately 3 mm (0.125 inch) of shaft spline visible.
NOTE: If hub is not seated, stop ring lugs are misaligned. Rotate ring until lugs are engaged in 3-4 hub slots.
24. Verify that second and third gear rotate freely at this point. If not, determine the cause and correct.
25. Invert mainshaft in case or bench.
26. Install first gear bearing on mainshaft.
27. Install first gear on shaft with clutch hub side of gear facing the front of shaft (Fig. 98). Verify tabs on clutch ring are aligned and seated in first gear hub.
NOTE: 1-2 synchro hub will not seat properly if clutch ring tabs are misaligned.
28. Install reverse clutch gear on first gear (Fig. 98). Verify clutch gear is seated on shaft splines.
29. Install reverse clutch gear snap ring with heavy duty snap ring pliers (Fig. 98). Verify snap ring is seated in groove.
NOTE: Reverse gear will not fit properly if snap ring is not seated.
30. Install stop ring on clutch cone (Fig. 99). Verify stop ring is seated on cone taper.