VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 3 Speed Vacuum Assist Shifting

My 1948 Fleetmaster Woodie Wagon has the 3 speed vacuum assist transmission. It sometimes works when shifting to 2nd and 3rd gears, but it more often than not grinds when shifting into these gears. Any idea why it works sometimes and others not?

Hi Buckaroo. In the manual there is an adjustment above the steering box on the gear change mechanism which limits the travel of the gearshift lever to 1 inch when the lever is pushed forwards. Sometimes this clearance is insufficient and the gears can clash on an impatient gear change. I also use silicone grease to lubricate the piston leather. Silicone seems to last longer than mineral oil.

There are many reasons for gear clash during shifts. The vacuum assist is only one. Others include linkage adjustment and lubrication, clutch adjustment and engagement issues, worn synchronizers, and low gear transmission gear lube.