Sower, as I said, I don't have a Lehner, but the Lehners are ranked right up there with the best of the equipment available.

Take it from me, even the best equipment available is subject to a failure here and there. How long is the warranty on the Lehner motor that you have? Maybe you can send it in.

With regard to motors in general, you do control the max rpms with the voltage. I've found that something around 30,000 works very well in a truck. The problem with the larger motor is that you may not be able to gear it high enough to put enough of a load on the motor just pushing around the relatively light truck. I'm also not sure of how much current a 2240 will pull when properly loaded.

You might need to look into the specs of the motor a bit before you jump on it. Did you ask why he is selling the motor? What is he replacing it with? Whatever he is replacing it with might be what you need to get. LOL.