tcase tranny problems

[hebertvinet]

i have just bought a 89 toyota truck, it is a 4x4 3.0L v6
has a 4 inch lift with 33 inch tires

here is my problem
every time i push the gas the 4wheel drive shifter along with auto shifter rocks back and forth. it also gives a knock on the floor at times. this does not happen in reverse
the guy i got the truck from said its a steady bearing. A mechanic told me it is probably a mount anyone have any ideas for me? thanks for your time and hope someone can help.

 

[pappy]

Start by looking at your engine mount, probably driver's side. It should move a little simply because of torque to the drive shaft. But it should not be much.

 

[hebertvinet]

thanks ill look now

 

[hebertvinet]

the mounts are good. but i tryed shaking the driveshaft and its loose. would that cause it to to that?