Cleaning and Inspection
SHIFT COVER INSPECTIONInspect the cover and shift components whenever the cover is removed from the gear case or whenever diagnosis indicates inspection is necessary.
Check the forks for wear, distortion, cracks, or being loose on the shift rails. Also check fit of the shift rails in the cover. Replace the cover assembly if the rails are loose in the cover bores.
Inspect and replace the pads on the fifth-reverse shift fork if worn. The expansion plugs at the rear of the cover can be replaced if loose or leaking.
A gasket is not used between the shift cover and gear case. Use MOPAR Gasket Maker, or equivalent, to seal the cover.
TRANSMISSION
Clean the gears, bearings shafts, extension/adapter housing and gear case with solvent. Dry all parts except the bearings with compressed air. Allow the bearings to either air dry or wipe them dry with clean shop towels.
Inspect the reverse idler gear, bearings, shaft and thrust washers. Replace the bearings if the rollers are worn, chipped, cracked, flat-spotted, or brinnelled. Or if the bearing cage is damaged or distorted. Replace the thrust washers if cracked, chipped, or worn. Replace the gear if the teeth are chipped, cracked or worn thin.
Inspect the drive gear and bearings. Minor scratches and burrs on the gear surfaces can be reduced with an oil stone and 400 grit paper wetted with oil. Replace either bearing if worn, or damaged. Replace the gear if any teeth, splines, or bearing surfaces are also worn or damaged.
Inspect the front bearing retainer and bearing cup. Replace the bearing cup if scored, cracked, brinnelled, or rough. Check the release bearing slide surface of the retainer carefully. Minor corrosion, nicks, or pitting can be smoothed with 400 grit emery and polished out with crocus cloth. Wet the abrasive paper and crocus cloth with oil when smoothing/polishing. Replace the retainer if worn or damaged in any way. Do not reuse the original retainer bolts. Install new bolts during assembly.
Inspect the countershaft and bearings. Replace the bearings if worn, rough, flat spotted, or heat checked. Check the countershaft gear teeth carefully. Small nicks, scratches, or burrs can be removed with an oil stone and 400 grit paper wetted with oil. However, replace the shaft as an assembly if the forward gear is loose, or any of the teeth are worn, cracked, broken, or severely chipped.
Be sure to check condition of the countershaft bearing cups. Replace either bearings cup if worn, or damaged.
Check condition of the mainshaft. Inspect all the bearing surfaces, splines and threads. Also check condition of the snap ring grooves in the hub area and the speedometer drive gear teeth. Minor scratches or burrs can be removed with an oil stone and polished with crocus cloth. However, replace the shaft if any surfaces exhibit considerable wear or damage.
Check condition of the gear case and extension or adapter housing. Be sure the alignment dowels in the case top surface and in the housing/adapter are tight and in good condition.
Run a tap through the gear case bolt holes if the threads need minor cleanup. Helicoil inserts can be used to repair seriously damaged threaded holes if necessary.
Be sure all case and housing/adapter sealing and mating surfaces are free of burrs and nicks. This is especially important as gaskets are not used in the NV4500. Minor nicks and scratches on the sealing surfaces can be dressed off with a fine tooth file or oil stone.
Replace the gear case or housing/adapter if cracked or broken. Do not attempt to repair this type of damage by welding or brazing.
Check condition of the countershaft fifth gear components. This includes the shift lug and rail located in the gear case and the rail bushings.
Inspect the gear and hub assembly. Minor burrs can be cleaned up with an oil stone. However, the gear and hub assembly should be replaced if the teeth or splines are excessively worn, or damaged. The synchro sleeve should also be replaced if worn or damaged in any way. Do not reuse synchro struts that are worn, or springs that are collapsed or severely distorted. Replace worn distorted synchro parts to avoid shift problems after assembly and installation.
The shift fork should be inspected for evidence of wear and distortion. Check fit of the sleeve in the fork to be sure the two parts fit and work smoothly. Replace the fork if the roll pin holes are worn oversize or damaged. Do not attempt to salvage a worn fork. It will cause shift problems later on. Replace the shift fork roll pins if necessary, or if doubt exists about their condition.
The bearings should be examined carefully for wear, roughness, flat spots, pitting, or other damage. Replace the bearings if necessary.
Inspect the stop ring and clutch gear. replace either part if worn or damaged in any way. Also be sure replacement parts fit properly before proceeding with assembly.
Examine the 1-2 synchro hub and sleeve for wear or damage. Replace the sleeve and hub if the splines are worn, chipped or damaged.
Replace the synchro struts if worn, or chipped. Also replace the springs if collapsed, distorted, or broken.
Inspect the mainshaft gear-train components. Check the teeth on all gears, hubs, clutch gears, stop rings and clutch rings. The teeth must be in good condition and not worn, cracked, or chipped. Replace any component that exhibits wear or damage.
Examine the synchro stop rings, clutch rings and clutch gears. Replace any part that exhibits wear, distortion, or damage. Replace the clutch rings if the friction material is burned, flaking off, or worn.
Inspect all of the thrust washers and locating pins. Replace the pins if bent, or worn. Replace the washers if worn, or the locating pin notches are distorted.
Check condition of the synchro struts and springs. Replace these parts if worn, cracked, or distorted.