It's typically very difficult.

First you need to remove the roll pin that holds the wheel to the axle. Now soak the axle with a good penetrant.

If your seal leak isn't too bad then just use the tiller normally until the wheel starts to fall off. (It's actually one of the more effective ways to get it off intact.)

The other method is to cut it off or drill a couple holes and rig up some form of puller.

Whatever you do don't beat on it or don't pull on it without keeping the axle in it's original condition. If you do, you'll likely damage the tranny.

hello,

ilossened up entire an 8 foot disk last year witha setaline torch. i kinda dought u just have a seteline torch laying around but u could prolly do a job like that with just a plumber's torch. the only thing is if the axle has lube, grease or gasoline any where near it there is a fire danger...this is definetly a job for a full ploy face mask or a welders helmet. if u used wd-40 or anything like that yes it will catch on fire but it woulnt explode to the extend that gass will...wd-40 could possibly help to heat up the inside of the joint as it burns. i would suggest trying to drive the machine with out the bolts as the previous poster said first and this as ur last result. do not heat the metal to hot as it can get so hot that it becomes brittle and breaks easily(should only be problem with a larger torch. also make sure u dont melt ur tires(deflating and removing them wouldnt be a bad idea). if u have any qpestions about this just post them...ill be checking back.

Along with the other remedies this sometime makes the difference. Get the largest fine thread nut you can that has a smaller id then the axle hole in the wheel. Have a welding shop wire feed weld it to the end of the wheel. Then, using a long push bolt in the added nut you may get it to come off.

Once you get them off take notice. Clean everything up nice and polished and apply a liberal amount of anti-seize or axle grease when assembling. Repeat once a year as part of maintenance schedule.

the walrus is more like a dolphin...quite smart(the guy above^). Never thought that idea before but it seems like it would work. u would be able to wack the nut off the end or even leave it incase this happens again. a right angle grinder takes care of those stuck on welds very easy....i got mine for less than 30 bucks at harbor frieght(discount tool store) it may not be dewalt but it suites the couple time a year metal worker quite well.

Consider using PB blaster and a steering wheel puller.

There is a tool made just for this. It was designed for a mower shop to be used over and over. You could buy one use it to loosen all your wheels then resell it for almost the same price.
Sometimes you need to remove the wheel for tire repair and you don't want to heat the axel and destroy the seals. If you need to remove a tiller wheel easily check out this video of a new tool
http://www.youtube.com/watch?v=9AGgaEFfgNQ

Here is a link that might be useful: Wheel puller

I just thought I should second davefr above for the 'remove the pin and use it 'til it falls off' method because that is SPECIFICALLY what the manual recommends.

I have a simple solution, may take couple hours to put together and about 5-10 minutes to remove the frozen wheel. But once you put this together, you can reuse as often as you wish. 2 pieces of unistrut in back of the wheel bolted to pieces in front with 5th piece between the front 2 unstructured and the front side of wheel. Through that 5th piece, install a bolt to the end of axle and start screwing it in. May take a strong arm to break it free but it works super. I heard 2 loud pops when it came loose and the rest was easy. Best of all, no hammering and no heat. I used longer unistrut than needed for tiller, made them long enough for my mower also.