Alright guys, newer truck:
2008 Ford Ranger XLT
4.0L V6 SOHC
40k Miles
5 Speed Automatic Transmission
4x4
4.10 LSD

Whenever I shift into reverse, there is a pause (which I think is normal, for the driveshaft to engage reverse), but it usually jerks after the pause, and sometimes if I press the gas after it jerks, it jerks again like as if it wasn't in gear after all. Could this be a fluid problem, I would like to find out, because if the U-Joints or something are damaged, the dealer I bought it from can replace them for free (or I can call my attorney)... Thanks guys

 

Mine does the same occasionally... but definitely not every time.

 

I am still having this problem. Whenever I go into reverse, at a complete stop, from drive, it jerks hard (and you can hear it) (sounds worse than when you go into 4L), and then if you let go of the brake, the truck doesn't move, and if you give it a little gas it jerks really hard again and then moves backwards

Please help guys, i need to know what is wrong before i blow a transmission or differential

 

Never mind guys, I think I may have found the culprit. I completely forgot that when you check the transmission fluid, the engine needs to be running and the temperature of the engine should be normal, not cold and not too hot. I let the engine run a little to warm up, and even shifted a few times. When I checked the dip stick, transmission fluid only covered the bottom of the dipstick, and was no where near the crossed line area, I assume that I am low on fluid and will stop by the dealer tonight