i had somewhat of a problem like yours,you may want to check your universal joints.also trans fluid level and filter.just some ideas. joe 
If it was a U-Joint the Shaft would have probably come out and hit the ground. Any noises??blinky_1986 said:um i just did a lil check if i put the car on stands every gear works i.e wheels spinning drive shaft spins but if its on the ground it wont pull only in reverse ..... trans is new fluid good filter good how would i check for a u joint??
Any problem I've had with a converter,it had problems in all gears.hemi joe said:prostreet6t9 could this be aproblem with torque converter?i had a broken keyway,had trouble with forward gears but reverse was fine. joe
When you loose motion,does the Driveline spin?blinky_1986 said:negative on noises a clunk but that could be u joint im just not sure if that would prevent any motion period