NV4500 and NV4500HD Transmission
FIFTH GEAR NUT REMOVAL-STANDARD DUTY1. Remove mainshaft fifth gear nut as follows:
Fig. 24:
a. Install nut wrench on fifth gear nut (Fig. 24). Use Nut Wrench 6443 on standard duty models.
b. Note that wrench only fits one way on nut. Be sure wrench is fully engaged in nut slots and is not cocked.
c. There are two splined sockets available to retain the mainshaft; while removing the fifth gear nut.
^ Socket 6441 fits standard duty 4X2 mainshafts.
Fig. 25:
^ Socket 6442 fits standard duty 4X4 mainshafts. Install breaker bar in appropriate socket wrench (Fig. 25).
d. Wedge breaker bar handle against workbench. Purpose of socket wrench and breaker bar is to prevent mainshaft from turning while nut is loosened.
e. Position small end of Nut Wrench 6443 at approximately 10 o'clock position (Fig. 24).
f. Strike small end of nut wrench with heavy copper hammer to break nut loose. Nut is secured by interference fit thread plus Loctite adhesive and will require several firm blows to loosen it (nut torque is in 300 ft. lb. range).
g. Once nut is loose, it can be removed by holding nut wrench with breaker bar and rotating output shaft with socket wrench and ratchet.
Fig. 26:
h. Remove and discard fifth gear nut (Fig. 26).
2. Remove the belleville washer from the mainshaft.
FIFTH GEAR NUT REMOVAL-HEAVY DUTY
1. Loosen fifth gear clamp nut clamping screw approximately 1 1/2 turns.
2. Remove mainshaft fifth gear nut as follows:
Fig. 27:
a. Install nut wrench on fifth gear nut (Fig. 27). Use Nut Wrench 6743 on heavy duty models.
b. Note that wrench only fits one way on nut. Be sure wrench is fully engaged in nut slots and is not cocked.
c. There are two splined sockets available to retain the mainshaft while removing the fifth gear nut.
^ Socket 6993 fits heavy duty 4X2 mainshafts.
^ Socket 6984 fits heavy duty 4X4 mainshafts. Install breaker bar in appropriate socket wrench (Fig. 27).
d. Wedge breaker bar handle against workbench. Purpose of socket wrench and breaker bar is to prevent mainshaft from turning while nut is loosened.
Fig. 28:
e. Remove and discard fifth gear nut (Fig. 28).
3. Remove the belleville washer from the mainshaft.
FIFTH GEAR REMOVAL
Fig. 29:
1. Remove roll pins that secure countershaft, fifth gear shift fork to shift rail with pin punch (Fig. 29). Roll pins are driven out from bottom of fork and not from top.
Fig. 30:
2. Remove snap ring that secures fifth gear clutch hub and gear on countershaft (Fig. 30).
3. Remove fifth gear shift fork and gear assembly. Remove assembly by tapping fork off rail with plastic mallet.
4. Remove countershaft fifth gear clutch gear and stop ring.
5. Remove fifth gear shift fork from sleeve.
6. Remove sleeve, struts, and strut springs from countershaft fifth gear hub, if necessary.
Fig. 31:
7. Remove countershaft fifth gear needle bearing assembly (Fig. 31).
Fig. 32:
8. Remove cone shaped rear bearing thrust washer from end of countershaft (Fig. 32). Note position of washer for assembly reference. Also note that washer bore has notch for locating pin.
9. Remove and retain thrust washer locating pin from countershaft.
10. Remove mainshaft overdrive fifth gear with Puller Tool Set 6444. Note that puller set can be used on both standard and heavy duty transmissions.
11. Gear removal procedure is as follows:
Fig. 33:
a. Position first puller jaw on gear (Fig. 33). Use Puller Jaws 6459 on standard duty models and Puller Jaws 6820 on heavy duty models.
Fig. 34:
b. Assemble Puller Flange 6444-1 and Puller Rods 6444-3 for 4X2 vehicles, or 6444-4 for 4X4 vehicles, (Fig. 34).
c. Slide assembled puller flange and rods onto output shaft. Then seat flange in notch of puller jaw (Fig. 34).
Fig. 35:
d. Position second puller jaw (6459 or 6820) on gear and in notch of puller flange (Fig. 35).
e. Slide Retaining Collar 6444-8 over puller jaws to hold them in place (Fig. 35).
Fig. 36:
f. Install Puller and Bolt 6444 on puller rods. Then secure puller to rods with retaining nuts (Fig. 36).
g. Tighten puller bolt to remove gear from shaft splines (Fig. 36).
Fig. 37:
12. Remove bolts attaching mainshaft, rear bearing plate to gear case and remove fifth gear plate end play shims and bearing cup (Fig. 37).
FRONT RETAINER REMOVAL
Fig. 38:
1. Remove front retainer bolts (Fig. 38). Discard retainer bolts. They should not be reused.
2. Remove front retainer by lightly tapping it back and forth with plastic mallet to loosen it. Then rock retainer back and forth by hand to work it out of gear case. Note that retainer flange extends into the transmission case and is a snug fit into case bore.
Fig. 39:
3. Remove seal from front retainer (Fig. 39). Use small chisel to collapse one side of seal then pry it out with suitable tool.
4. Remove bearing cup from front retainer as follows:
Fig. 40:
a. Assemble Puller Flange 6444-1 and Puller Rods 6444-4 (Fig. 40).
b. Insert Puller Jaws 6453-1 in puller flange (Fig. 40). Narrow lip of puller jaws will go under bearing cup.
c. Install Disc C-4487-1 into bearing retainer on heavy duty transmissions for Insert 6453-2 to rest upon.
Fig. 41:
d. Install assembled tools in front retainer (Fig. 41). Be sure puller jaws are seated under bearing cup.
e. Place Insert Tool 6453-2 in center of puller jaws (Fig. 41). Insert tool is used to hold puller jaws in place.
Fig. 42:
f. Install Puller 6444 on puller rods (Fig. 42). Then install retaining nuts on puller rods.
g. Tighten puller bolt to draw bearing cup out of retainer (Fig. 42).
DRIVE GEAR REMOVAL
Fig. 43:
1. Remove drive gear (Fig. 43).
Fig. 44:
2. Remove pilot bearing from drive gear (Fig. 44).
3. Remove tapered bearing from drive gear as follows:
Fig. 45:
a. Assemble Puller Flange 6444-1 and Puller Rods 6444-6. Then position first Puller Jaw 6447 on bearing (Fig. 45).
b. Slide assembled puller flange and rod tools onto input shaft. Then seat flange in notch of puller jaw (Fig. 45).
c. Position second Puller Jaw 6447 on gear and in notch of puller flange (Fig. 45).
d. Slide Retaining Collar 6444-8 over puller jaws to hold them in place (Fig. 45).
e. Install Puller 6444 on puller rods. Then secure puller to rods with retaining nuts (Fig. 45).
f. Tighten puller bolt to remove bearing cone from drive gear (Fig. 45).
MAINSHAFT AND GEARTRAIN REMOVAL
1. Move 1-2 and 3-4 synchro sleeves into Neutral, if necessary.
Fig. 46:
2. Remove drive gear thrust bearing from forward end of mainshaft (Fig. 46).
Fig. 47:
3. Remove fourth gear clutch gear and synchro stop ring from mainshaft (Fig. 47).
Fig. 48:
4. Roll gear case onto left side (Fig. 48).
5. Remove mainshaft assembly as follows (Fig. 48):
a. Lift front end of mainshaft slightly. Use care when handling the mainshaft because the gears will be lose on the mainshaft.
b. Grasp mainshaft rear splines. Then turn spline end of mainshaft in counterclockwise direction to rotate shaft and geartrain out of case.
c. Once mainshaft gears roll clear of countershaft gears, shaft and gear assembly can be tilted outward and removed from gear case (Fig. 48).
REVERSE IDLER AND COUNTERSHAFT REMOVAL
Fig. 49:
1. Remove countershaft rear bearing plate (Fig. 49).
Fig. 50:
2. Remove countershaft, end play shim and rear bearing cup (Fig. 50).
Fig. 51:
3. Remove reverse idler shaft (Fig. 51).
Fig. 52:
4. Rotate countershaft outward and push reverse idler gear away from countershaft and toward front of case (Fig. 52).
Fig. 53:
5. Remove idler gear (Fig. 53).
Fig. 54:
6. Keep reverse idler gear bearings and spacer together for cleaning and inspection (Fig. 54). Insert idler shaft through gear and bearings to keep them in place.
7. Remove idler gear thrust washers from gear case. Install washers on idler shaft to keep them together for cleaning and inspection.
8. Remove countershaft, rear bearing. Shaft cannot be removed from case until rear bearing has been removed. Bearing removal procedure is as follows:
Fig. 55:
a. Assemble Puller Flange 6444-1 and Puller Rods 6444-4 (Fig. 55).
b. Position first Puller Jaw 6449 on bearing cone (Fig. 55).
c. Seat puller flange in notch of puller jaw just installed on bearing cone (Fig. 55).
d. Install second Puller Jaw 6449 on bearing and in notch of puller flange (Fig. 55).
e. Slide Retaining Collar 6444-8 over puller jaws to hold them in place (Fig. 55). Note that retaining collar has small lip on one end and only fits one way over jaws.
f. Install Puller 6444 on puller rods. Then secure puller to rods with retaining nuts (Fig. 55).
g. Tighten puller bolt to remove bearing from shaft (Fig. 55). If bearing is exceptionally tight, tap end of puller bolt with copper mallet to help loosen bearing.
9. Remove bearing puller tools.
Fig. 56:
10. Rotate countershaft out of gear case (Fig. 56).
11. Remove countershaft front bearing as follows:
Fig. 57:
a. Assemble Puller Flange 6444-1 and Puller Bolts 6444-4 (Fig. 57).
b. Position first Puller Jaw 6451 on bearing.
c. Seat puller flange in notch of puller jaw.
d. Install second Puller Jaw 6451 on bearing and in notch of puller flange.
e. Slide Retaining Collar 6444-8 over puller jaws to hold them in place (Fig. 57). Note that retaining collar has small lip on one end and only fits one way over jaws.
f. Install Puller Bridge And Bolt Assembly 6444 on puller bolts. Then secure bridge to bolts with retaining nuts (Fig. 57).
g. Tighten puller bolt to remove bearing from shaft (Fig. 57). If bearing is exceptionally tight, tap end of puller bolt with mallet to help loosen bearing.
12. Remove bearing puller tools.
13. Set countershaft, and idler gear aside for cleaning and inspection.
GEAR CASE DISASSEMBLY
Fig. 58:
1. Remove countershaft front bearing cap. Use mallet or hammer to remove cap from inside case (Fig. 58).
Fig. 59:
2. Remove countershaft front bearing cup with Remover Tool 6454 and Tool Handle C-4171 (Fig. 59).
Fig. 60:
3. Remove roll pin that secures shift lug on shift rail in case (Fig. 60). A small pin punch can be modified by putting a slight bend in it to drive pin completely out of shift rail (Fig. 60).
4. Remove shift lug rail.
MAINSHAFT DISASSEMBLY
NOTE: Not all of the mainshaft gear and synchro components are a one-way fit. Some gear and synchro components can be installed backwards. To avoid reassembly problems, mark the gear gears, clutch gears, synchro hubs, and sleeves for reference during teardown. Use paint or a scriber for marking purposes. Then stack the geartrain parts in order of removal. This practice will help avoid incorrect assembly and lost time.
1. Remove drive gear thrust bearing from end of mainshaft, if not previously removed.
Fig. 61:
2. Remove 3-4 synchro hub, third gear stop ring and third gear as an assembly (Fig. 61). It is not necessary to disassemble the synchronizer components unless worn or damaged.
Fig. 62:
3. Remove third gear bearing from mainshaft (Fig. 62).
Fig. 63:
4. Remove third gear bearing spacer (Fig. 63).
5. Remove snap ring that retains second gear thrust washer on mainshaft (Fig. 63).
Fig. 64:
6. Remove second gear thrust washer (Fig. 64). Note that washer is notched for locating pin.
Fig. 65:
7. Remove thrust washer locating pin (Fig. 65). Use needle nose pliers to grip and remove pin.
Fig. 66:
8. Remove second gear (Fig. 66).
Fig. 67:
9. Remove second gear bearing (Fig. 67).
Fig. 68:
10. Remove snap ring that retains second gear clutch cone (Fig. 68). Snap ring is seated in mainshaft synchro hub groove.
Fig. 69:
11. Remove second gear clutch cone, synchro clutch ring and synchro stop ring (Fig. 69).
Fig. 70:
12. Remove 1-2 synchro hub snap ring (Fig. 70).
Fig. 71:
13. Remove 1-2 synchro sleeve, hub, struts and springs as an assembly (Fig. 71). Note that tapered side of sleeve also goes toward front. It is not necessary to disassemble synchro components unless worn, or damaged.
Fig. 72:
14. Remove first gear synchro stop ring and clutch ring (Fig. 72).
Fig. 73:
15. Remove first gear clutch cone front snap ring from mainshaft hub (Fig. 73).
Fig. 74:
16. Remove first gear clutch cone (Fig. 74).
17. Remove first gear clutch gear rear snap ring from mainshaft hub (Fig. 74). It is not really necessary to remove this snap ring unless it, or the mainshaft is to be replaced.
18. Remove the mainshaft rear bearing as follows:
Fig. 75:
a. Assemble Puller Flange 6444-1 and Puller Rods 6444-3, for 4X2 applications, or 6444-4, for 4X4 applications (Fig. 75).
b. Position the first Puller Jaw 6445 on the bearing cone.
c. Seat Puller Flange 6444-1 in notch of first puller jaw.
d. Install the second Puller Jaw 6445 on the bearing cone and puller flange.
e. Install Puller 6444 on the puller rods and secure with nuts.
Fig. 76:
f. Place a holding wrench on the hex portion of Puller 6444 (Fig. 76) and tighten the forcing screw against the output shaft. Continue tightening the forcing screw until the bearing is removed from the output shaft.
g. Remove the bearing puller tools and the rear mainshaft bearing from the output shaft.
Fig. 77:
19. Remove reverse gear thrust washer (Fig. 77).
Fig. 78:
20. Remove reverse gear and synchro components as assembly (Fig. 78). It is not necessary to remove or disassemble synchro components unless they are damaged and need to be replaced. If synchro sleeve or struts require service, mark position of sleeve on hub before removal. Correct sleeve position is important as sleeve can be installed backwards causing shift problems.
21. Remove reverse gear bearing assembly from mainshaft (Fig. 78).
Fig. 79:
22. Remove reverse gear bearing spacer from mainshaft (Fig. 79).
23. Remove reverse clutch gear snap ring (Fig. 79). Tension of this snap ring is considerable. Heavy duty snap ring pliers will be required to spread the ring far enough to remove it.
Fig. 80:
24. Remove reverse clutch gear (Fig. 80).
Fig. 81:
25. Remove first gear from bearing and mainshaft (Fig. 81).
Fig. 82:
26. Remove first gear bearing from mainshaft (Fig. 82).