Inspection Pointers: Tranny clatter

Collectors often give engines a once-over before buying. Transmissions, however, frequently get overlooked. And for good reason, since they don't usually pose serious restoration problems. Still, it doesn't hurt to inspect the transmission to discover potential pitfalls during restoration. Also remember that it is oftentimes far easier to get a replacement for a bent rod, broken valve, or scored cylinder than to find parts for transmissions.

If the tractor runs, take it for a drive. Shift through all the gears first to determine if all the ranges are still available. Listen for gear teeth chatter. This is the clicking sound gears can make when they are missing some teeth when the tractor is driven at a particular speed. Pay particular attention to a tractor's most commonly used working or field gears since they've taken the most punishment and will show the most wear. So too, excessive wear can occur if the tractor was used as a stationary power unit in its later years of employment on the farm. Wear can occur to the transmission even if the tractor was operating in neutral for long periods of time.

And don't ignore roading gears when evaluating a tractor. The gears in this set can sometimes be stripped as a result of operators who downshifted the transmission before the tractor came to a stop.

When the engine is turned off, it should be impossible to turn the PTO shafts. If it turns, then this indicates the possibility of serious internal damage to the transmission. Otherwise, start the tractor and check if the PTO starts and stops immediately when engaged and disengaged.

Utah State University offers an inspection guide to used tractors here.