76 400 track noise

[greenblood]

I have a 76 400 that runs like a top (try to wipe the smile from my face


). I just had it out Sunday in the new snow that has finally blanketed the upper midwest!

While running around the farm, I would get a terrible ratcheting noise coming from the drive area of the track when I would hit a drift, or lump of snow. Sounds like the track rubbing on the top of the bogie support or something. The sled seems to accelerate without slipping or causing the same noise.

The track is in very good condition, and appears to have good tension. I haven't found a service manual yet, so I'm not sure on the specs for the track adjustment.
The drive sprockets look good with minimal wear.

Any other ideas?

Thanks for the help!

[Danzig]

Up inside the tunnel, there are 2 track support guides as I call them that the track runs on. The track should be adjusted to have about 1/2-3/4 in. of movement on top of these support guides.


You could also have a loose chain in the chain case, I think (?) this has an automatic adjuster on that. I also think that on the adjuster itself has a nylon wear block that could also be worn out, thus a loose drive chain.

[greenblood]

Thanks Paul. I missed one little detail when checking track tension. Actually reading the manual is a great help. The manual says to have someone sit on the sled when checking the track. That is when I had a 'Homer' moment (Duhooo!). Turns out the track would sit on the guides with weight on the seat. A few wrench turns later (believe it or not, none of the threads were rusty!) and the track was ready to go. Now to enjoy the 20+ inches we have gotten over the last week!




Track tension also clears up the 27 year old mystery of why my '72 400 made a similar noise when accelerating. If only I still had it...