If you can't get the wheel/ tire assembly off the machine, i'd suggest you try to do the tire changing on the machine.
The problem is as you say--wheels rusted on tight! But, if you try to beat or jack the wheels off the axles, you stand the chance of breaking something inside the transmission! Those inner parts are very hard to find any more, almost impossible, and if broken, and new ones found, the job of replacing them should be left to a seasoned mechanic familiar with Troy-bilt tillers.
I brought up a blow-up picture of the transmission from someplace, and it's mind boggling.
So, with the preceding in mind, saw the old tires into pieces, get the inner sides of the rims cleaned and painted, along with the outsides, mount the new tires, and yer ready to go. I'd suggest using inner tubes, but the purists here say mount them tubeless, which is not in my work schedule! I guess i'm a "cop-out"!
by: Rustyj

8-27-06 4:45 pm Thanks "Rusty", for the advice on the wheels
and prompt response.I will try this when I find some tires. Now the question is where to get the tires and @ what price. They are Carlisle 4:80/4:00-8(16.6 x 5.0 x3.75) Will search the internet and see if I can locate a set cheap..Or I might try my luck @ attempting to insert a tube in the old tubeless tire that keeps going flat,without taking the wheel off and if successful,will do the other side, when it starts to leak??? Don't know how much difficulty I will run into, while attempting to do this inner tube thing..Anyone ever try to do this with the old original tubeless tires???
I read this advice from a gent in an old forum, but he did not offer any slick ideas on how best to tackle this tube inside the old tubeless tire trick.Worth a try, I say and thanks to the reader that offered the advice. If anyone else wants to offer any advice or come up with a better suggestion or has done this, I would appreciate your comments..Thanks again friends...

If the leak is a slow leak and not a big hole i think i would try some "Slime" first. I buy it at Walmart and i have used it in my old Troybilt Horse tubeless tires and also have used it on riding mower tires, wheelbarrow tires and on an old truck tire. Just follow the directions and you shouldn't have a problem. You can fid it in the automotive section around 10 bucks.

Thanks nod72 for your suggestion. I forgot to mention earlier that I tried the slime trick about a year ago and it may have slowed it down some, but did not seal completely. Still goes down in about 2-5 days, which isn't bad but still a hassle.Tires are original and dry rotted(some small cracks in sidewall) but has good tread (16 years old) When I get my fall turnips,mustard and green onions going in a few weeks, may try to deflate the tire, clean the rim and tire bead,put a coat of rubber cement around the bead/rim,and attempt to reseat and seal..will let everybody know if this is successful..Any other suggestions or comments Very Welcome and appreciated. Thanks again for your responses..

To install tubes in the tires, you'll have to break the side-walls away from the rims. to do this, it can be done with large C-clamps, by tightening the clamp against both side walls, and turning it in until they pull away from the rims. To get it all the way off, lubricate the tire bead and rim with oil or grease, and carefully pry the tire off the rim.
After cleaning and priming/ painting the inside of the rim, and its' dry, lube the inner bead of the tire, and force it onto the rim, using a rubber hammer. Now, with the one bead inside the rim, and the other bead not, spread the tire out and stuff the inner tube inside, spreading it out all around the rim. Stick the valve out thru its hole, and tie a string to it. Before installing the tube, you should pump the tube up enough to get the wrinkles out of it, then let the air back out of it!, and install it, as above.
Then, after its inside the tire, carefully get the other bead of the tire onto the rim! Be careful the valve doesn't slip into the rim!(The string) Now, pump the tire up to seat it on the rim, watching that no part of the tube is caught between tire and rim! Then leave the air back out until it has gone down well. Using the rubber hammer, pound on the tire so any wrinkles in the tube will be gone, then reinflate it, and you should be good to go! (With the rim off the machine, we used to bounce it on the pavement)
All of the preceding is a tried and perfected method of replacing tires and tubes, as taught to me by The Gulf Oil company service station schools, way back in 1946! We had no fancy tire repair machines, nor tubeless tires, no Flat-fix, Slime, nothing except hard work!
HTH: Rustyj

Thanks again for the info on tire removal and replacement and installing the tubes. Sounds like the same method I used in the 40's when I replaced the tires & tubes on my 41 Chevrolet, except that I did not have the rubber mallet. Only had a big screw driver and a big hammer. Guess the procedure will work on almost any wheel and tire,if you have the muscle, patience and nuckles.I have a couple large C clamps, will see if they are big enough to do the job.Made a copy of all the info I've received on replacing the wheels and will put it with my parts manual and will steer away from trying to remove the rims for fear of damaging the transmission gears etc.
Hope the tires will come off without too much trouble. Will send fol-up later.appreciate the info..have a great day!