Thinking something in Transmission is broken

[Timber]

What thoughts do you have about this ?
my EXT trailblazer won’t move under its own power. When I put it on jack stands and shift it the rear wheel will spin. I can hear the transmission shifting from gear to gear I am thinking best thing to do is remove transmission and have it rebuilt and hear what the builder has to say after he pulls it appart.

 

[Mooseman]

Could be likely the clutches are so worn or the oil pump is so weak that it can't hold any real torque but able to move the wheels without resistance applied to them. If you have a 4x4, confirm the transfer case is not in neutral.

 

[JayArr]

There is a service port on the side of the transmission where you can check the line pressure without removing the transmission.

 

[mrrsm]

This "Official" ATSG 4L60E-4L80E Code and Diagnostic PDF Manual will prove helpful with those Testing Procedures: