how many u-joints
 

i took my car in to get u-joints replaced since i had a shudder, and they did it, but the car still shudders around 40mph when accelerating fairly slow. are there more than 1 they could have fixed? or could it be something else?

you just have one u joint. Could be the motor mounts or transmission mount

There's two u-joints: one by the trans, and one by the diff.

maybe that's the problem ur car only has one ujoint, lol.