Front-tine tillers have the tines (blades) located in front of the wheels and underneath the engine. In rear-tine tillers, the digging tines are located behind the wheels and there are 2 main types - standard rotating tines and counter rotating tines.

On most front tine tillers the gear box is a sealed unit and does not need greased. This may vary with manufacturers however; so it is recommended that it is verified with the specific manufacturer.

Murray

It depends on how your using it. For medium to large gardens and ground breaking, use a self propelled rear tine tiller. A reverse gear is a must, rear tine tillers are quite heavy and you can hurt your back trying to pull it back when in tilled soil. For light tilling and cultivating in flowerbeds, used a mid or front tine tiller, they are small and very easy to manuever because of their size. The downside of rear tine tillers is their size and cost, they are very large and cost anywhere from $400 to $3000. The downsides of mid or front tine tillers is they are very difficult to manuever if you are not paticulary strong or have a bad back, they will jump if they hit a rock, are not very powerful, and often lack safety shields around the tines, they also cannot till very deeply in hard soil. They cost anywhere from $100 for string trimmer mounted models to $200 or $300 for self contained mid or front tine tillers. I have a troy-bilt Pony that has lasted through twenty years of hard work and is a great rototiller.

To use a rototiller, first start it. Then move it out to the area to be tilled. Set the tines on the ground to be tilled and engage the tines. It should dig right in. On a self propelled rear tine tiller, all you have to do is follow along behind it keeping a downward pressure on the handles so that the tines stay in the soil. On a mid or front tine tiller that is not self propelled, you have to push the tiller forward and keeping a downward pressure on it so it digs in, but not too much pressure or will it dig it self into a hole. With all tillers, but paticulary smaller front or mid tine tillers, keep an eye out for rocks or sticks or roots or clay soil, this will cause the tiller to jump if it strikes it and it can be possible to lose control of it with smaller tillers. Sticks may tangle the tines in small tillers. Always keep your feet and hands away from the tines unless the engine is turned off.