Differential Adjustment

[Bob Culver]

Nothing is forbidden and much is possible. Total backlash includes the differential spur gears so means little. And unless the cwp was originally set up very correctly and is very unworn even the backlash of the cwp alone (latter can be wedged thru the drain hole) is a doubtful indicator.  When first asembeld the side adjustment is supposed to just support the cw laterally with no movement but this state is not easy to establish.Should not be able to lever  the cw laterally thru the plug hole. Adj is normally by slackening one and then tightening the other. Unless there is actual movement any existing preload is uncertain and it is not prudent to much increase blindly but if has done  high mileage and assembled OK originally with no subsequent careless change of divider gasket thickness,  can bring up the lhs a little. Adjusters are 20 tpi with 14 teeth and the cover plate enables half moves so can work out the effect. Certainly one half tooth reasonable. It is vital bearings not over compressed.
All mesh can be adjusted externally but gears develop wear steps and unless removed significant adj can move mesh onto these with puzzling effects. Mesh pattern can be marked thru the drain hole but all very tedious in place, and can fritter hours seeking an ideal pattern not acheivable with used gears. Older books as likely held by VCC cover the patterns and noises.
The oil is an indicator of conditon. If like silver paint the pinion is probably well worn. Generate a huge amount of metal and noise before likely to fail.