Hi,
I notice you have not gotten any response, so I will give it a shot, even though I, too, have recently come to own a Trail Boss and am just beginning to learn about it.
Generally speaking, parts availability is very thin. Especially for the transmission, which apparently are entirely unique to the Trail Boss. However, this vendor mentions some availability here:
http://richardsrelics.com/details_pa...rra_trans.html
and here:
http://richardsrelics.com/details_pa...errabands.html
(read somewhere that one version of the transmission has unfixable/unrelinable bands; this doesn't really make sense to me; if one human made something, another human can make a duplicate.
and here:
http://richardsrelics.com/details_pa...atranskit.html
(Let's be honest, these are just standard seals packaged up at a rather high price. But if someone didn't want to go to the trouble of figuring out all the sizes, or wait for me to figure them out and post the information.)
The engine is just a two-cycle Kohler Snowmobile engine which seems to be pretty bulletproof. The carburetor is a Tillotson HR38A, which is apparently common as dirt. This company bought the Kohler two-cycle business in 1981:
Growth Products, Inc.
http://www.growthprod.com
Phone:989-235-4294
124 S. Lake St
Crystal, MI 48818
The drive pulleys are standard snowmobile stuff, and are readily available, including at Richards Relics (referenced above).
The body is made from High Density Polyethylene. This is the same stuff kayaks are made of, and repairs using heat and the proper plastic filler rod are widely documented on youTube, and such (supplies:
https://www.polyvance.com/HDPE-1/). It can not be painted (well, it can be painted, the paint just won't stick and will eventually come off).
The remaining engineering for the Trail Boss is pretty much of the "sledgehammer" variety and can be easily dealt with by anyone willing to work at it.
If anyone notices anything I have gotten wrong here, I will be delighted to hear of it, as any corrected information will prevent me from going down the wrong path.
Regards,
Tom Newell