If the stick up on the motor shaft is less than 1.5", the thrust bearing in the motor is bad and the motor will need to be replaced. The pump end will probably still be good, which will be half of a complete new unit. Some people won't put a new motor on and old pump, but I have done it lots of times. I am not a fan of putting a new pump on an old motor, but the other way around is OK.
The pump and motor are 3.5" diameter. If you have 5" or larger casing you can use a 4" shroud or flow inducer on the pump. If the thrust bearing is down, it is usually from a lack of flow going past the motor. A shroud makes the water go past the motor before it goes into the pump intake. IMO a shroud is THE most important part in making a motor last, especially a deep set, low volume pump like that.
If the casing is too small for a shroud, the best you can do is raise the pump in the well if possible, so that more water flows past the motor on the way up to the pump intake.