I am betting it is one of these hubs. I am deliberating if I should get it?
Sturmey-Archer Bicycle Hubs
The Sturmey-Archer AW 3-speed hub
any mechanics are scared of 3-speed hubs, and think of them as being impossibly complicated. The most common model, the Sturmey-Archer model AW, is quite easy to overhaul with the aid of Sutherland's. Other models, especially those with coaster brakes, can be tricky or impossible to repair, due to parts un-availability.
Even if you are too chicken to try taking a 3-speed hub apart, that shouldn't stop you from working on 3-speed bikes. The AW hub is the most reliable gear shifting mechanism ever made, and rarely needs anything more than a bit of medium weight oil every so often. 95 percent of shifting problems on 3-speeds are related to the control cable or the handlebar trigger unit.
When you remove and re-install a 3-speed rear wheel, pay particular attention to the axle washers. The axles are flatted, and there are special anti-rotation washers keyed to the flats on the axles. These washers have tabs that must face into the drop-outs to help keep the axle from twisting under load. The axle nuts are easy to strip because of the interrupted threads on the flatted axle, so you should lubricate them with medium-to heavy oil or grease. They do have to be tightened quite securely.