Camshaft and Timing Gear Train To replace bushing: Replace bushing using a driver set. Align oil holes in bushing and idler gear. Install bushing flush with surface of idler gear. Cap Screw (3) M6 x 12 If bushing clearance (bushing I.D. minus shaft O.D.) exceeds specification, replace bushing, shaft or both. IDLER GEAR - 3TN66 AND LATER 3TNA72 Removal/Installation 1 M37834 1. Remove timing gear cover. (See procedure in this group.) 2. Check backlash of timing gears. (See Checks, Tests and Adjustments in this section.) Idler Gear Shaft O.D.: Standard . . . . . . . . . . . . . 19.959 - 19.980 mm . . . . . . . . . . . . . . . . . . . . . . .(0.786 - 0.787 in.) NOTE:
Due to the odd number of teeth on the idler gear, timing marks will only align periodically. When all timing marks on gears are aligned, the piston closest to the water pump is at TDC on compression stroke. Number one cylinder is closest to the flywheel. Wear Limit. . . . . . . . . . . 19.93 mm (0.785 in.) If shaft diameter is less than wear limit, remove three cap screws and replace idler gear shaft. Measure idler gear bushing diameter. 3. Rotate crankshaft and align timing marks. 4. Remove snap ring, washer and gear. 5. Inspect all parts for wear or damage. (See Inspection/Replacement procedures.) Installation is done in the reverse order of removal.
Washer Snap Ring Idler Gear Bushing I.D.: Standard . . . . . . . . . . . . . . 20.00 - 20.021 mm . . . . . . . . . . . . . . . . . . . . . . .(0.787 - 0.788 in.) Wear Limit. . . . . . . . . . . 20.08 mm (0.791 in.) Clearance . . . . . . . . . . . . 0.15 mm (0.0059 in.) If bushing diameter exceeds wear limit, replace bushing. M37516 To replace bushing: Inspection/Replacement Replace bushing using a driver set. Align oil holes in bushing and idler gear. Install bushing flush with surface of idler gear. Inspect gear for chipped or broken teeth. Replace if necessary. Measure idler gear shaft diameter. If bushing clearance (bushing I.D.
minus shaft O.D.) exceeds specification, replace bushing, shaft or both. 1-66 4/7/95 AllTractorManuals.com M35492 M35492