MTD Snowthrower: Transmission Repair

During the next-to-last snowfall, the gearshift on our MTD snowthrower jammed in high gear, but the wheels turned much more slowly than usual. Slightly before the last snowfall, I removed the cover over the transmission and discovered what went wrong:

MTD Snowthrower - transmission failure

MTD Snowthrower – transmission failure

That rubber wheel should be resting on the circular transmission plate, but somehow it slid off the far right edge. The spring-loaded clutch cable then pulled the plate upward, so that the side of the wheel drove the edge of the plate. Ouch.

The plate rotates on a bearing around a post on the folded red steel support structure underneath it, which pivots on a rod across the transmission housing behind everything that’s visible here. That rod used to protrude through the housing, but it had slipped inside and moved the plate to the left enough to let the wheel fall off. Some awkward maneuvering got it back through the hole, which made the real problem obvious:

MTD Snowthrower - missing hitch pin clip

MTD Snowthrower – missing hitch pin clip

There’s supposed to be a cotter pin or hitch pin clip through that hole, with a washer matching the obvious wear marks:

MTD Snowthrower - replacement cotter pin

MTD Snowthrower – replacement cotter pin

That’s actually a spacing shim from a collection that I’ve used rather infrequently over the years, but it’s exactly the right thickness to make the answer come out right.

A few weeks later, we found the missing washer on the driveway at about the point where I first noticed the transmission wasn’t working. It’s in the box of parts, waiting for the new cotter pin to wear out.

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  1. #1 by Jason Doege on 4-May-2013 - 15:57

    I always feel a little betrayed when things that shouldn’t be wear items fail…

    • #2 by Ed on 4-May-2013 - 17:05

      Somewhere out beside the driveway there must be two little steel snippets that, if laid side to side, would be the missing cotter pin. That poor pin must resist all the side-to-side vibration from the transmission plate; it’s really not up to the job.

      I was tempted to use a hitch pin to get more steel in there, but … maybe next time.