Eaton Fuller Transmission Alignment Troubleshooting

Concentric Alignment of Transmission to Engine

Common Concerns Resulting from Misalignment

  • Direct gear slipout

  • Drive gear bearing failure

  • Premature input shaft spline wear from rear hub of two plate clutches

transmission concentric alignment

Concentric alignment

Concentric alignment means that the engine and transmission must have a common axis. The purpose of this section is to set forth the procedures to use in checking for possible misalignment.

The basic instrument needed for taking readings is a taper pointed dial indicator. The accuracy of readings is essential for correcting alignment problems. Clean all surfaces thoroughly before proceeding.

Important Note:

When taking the following readings, rotate engine by hand, do not crank the engine with starter. Remove spark plugs on gasoline engines, and release compression on diesel engines.
Note: Before dial indicating engine flywheel or flywheel housing, make sure engine crankshaft does not have excessive end-play. If it does, accurate readings cannot be obtained. Place dial indicator finger against the flywheel. Force crankshaft back and forth with pry bar. If end-play movement exceeds maximum as specified by the engine manufacturer, it will have to be corrected.

Worn Housings

Inspect for worn or fretted pilot on both the transmission clutch housing and the engine flywheel housing. The 1/4″ pilot lip of transmission clutch housing can wear into the flywheel housing either by transmission loosening up or after high mileage just from the road and engine vibration.

worn or fretted pilot

Any appreciable amount of wear on either part will cause misalignment and the part should be replaced.

worn transmission housing

The wear will generally be found from the 3:00 o’clock to 8:00 o’clock position.

Engine Flywheel Housing Pilot

engine flywheel housing pilot
flywheel housing total runout

Dial indicate the pilot or bore of the engine flywheel housing. Secure dial indicator to engine flywheel with tapered point against housing pilot. Rotate flywheel by hand. With chalk or soapstone, mark high and low points of indicator as it is being rotated.

The total runout will be the difference between the highest plus and minus readings. SAE maximum total runout for flywheel housing pilot is .008″ with No.1 and  No.2 SAE housings.

Flywheel Pilot Bore

Dial indicate pilot bearing bore of flywheel. With indicator secured to flywheel housing, move gauge finger to contact pilot bearing bore surface. Turn flywheel and obtain readings. SAE maximum total runout for the pilot bearing is .005″.

flywheel pilot bore

Transmission Clutch Housing

The transmission clutch housing face and pilot cannot be checked accurately in the field without special measuring tools. Recommended maximum runout for the transmission clutch housing face and pilot is .003″ with SAE No.1 and No.2 housings.

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