Mine were slipping yesterday on the first use this year and then stopped slipping after awhile. And you say the roller is down on the cam with 1/4" of free space at the bottom?

It might be like mine with a PTO lever on the left rear that engages and disengages the tines.

I could move the cam down more but the shift lever is already down against the tines guard. Still a fair amount of belt play. The tines will turn but as soon as they contact the ground to till they stop. You can see that the belts aren't turning. When I turn the engine off and the motor is in the up/engaged position there is play in the belts. I don't have a PTO lever to engage the tines. When I shift the engine "up" with the lever the whels and tines turn in unison. There is not separate lever for just the tines. Everywhere I look for belts the sizes listed for the two speed are 21-22". That's what mine measure but I still have slack. I'm baffled.

the serial number stamp in my troy bilt tiller is 172017, i have not been able to find any info for this, could someone please help, thank you for any help

I just went thru this a month ago!
And the answer was here on Gardenweb!
Here's the answer, sort of; NAPA 4L210.
They are shorter than the originals and work great, but on mine, so far, they don't allow the transmission to stay in gear. I have yet to try a stronger spring on the cam lever. Even so, it isn't too bad holding the lever down since the machine is so well balanced. Good luck!
By the way, I am also getting the carb rebuild kit from NAPA. Bad timing for me as I have never done this (rebuild a carb, thanks Youtube!) and needed to use the tiller, but once it is running it will do several other things around my work place.

I have a belt supplied by Troy about 20 years ago. It's brand new and I'll measure it tomorrow and get back here.

Bobby Miller your tiller was built between 7-1-75 to 1-1-76

In case you don't have a copy of the owner's manual for that model - the link below opens up a 180 page PDF copy of the original from '78 -'79. I don't suppose it had changed much in 2-3 years.

Here is a link that might be useful: Troy-Bilt Horse Roto Tiller Manual

Mine is a 1982 model with the PTO and uses only one belt. There are two pulleys for low and high speed and you can only choose one.

My belt is 22 1/2" X 1/2" wide X 3/8" thick. It's new.

where on the machine do i find the model number and serial number? ... we have a 1984 (?) troy built/garden way that belonged to my father-in-law. ... i can find "part #2412 (6/84)" marked on it; and "Kohler 8" ... ... but not the model or serial number.
. tom honea thonea1@gmail.com

i just bought a old troybilt and the best i canmake out of the numbers stamped on trans housing are 3j3335,am i reading then right or it cant be.the motor is 105107f hh60,it is electric start,i know i need a carb,and a throttle cable and all the springs and whatever to hook up carb to governor etc.the motor will start but when you rev it up and put it in gear it looses its rpms.i need help finding out what i got and fixing it back to tip top shape.any help,info,etc would be greatly appericated.thanks dwstoy

i have an older model horse. anyone know if oil seals on axel can be replaced without tearing down transmission?

I haven't looked at mine, but generally, oil seals can be pulled out from the outside. You can use a screwdriver or a real seal puller.