I recently purchased a 1966 Mark 2 3.8 with automatic transmission. When the gear selector is put in Reverse the car does not budge, it's as if it is in Neutral. I can rev the engine, but the car does not move. Drive works fine. Is there anything I can do to diagnose the problem or is this an issue for a qualified mechanic? Thanks.

 

If there is no grinding noise which sounds like something is broken I would assume it is just the alignment of the gear lever that is at fault. There are under the dash rods with adjusters that you can play with but first you need to find out if you actually have a reverse. With the engine running and your foot on the brake try sliding the gear lever very slowly between the markings on the dash, between neutral and park as this is where your reverse gear is going to be. The gear lever might not be aligned with the markings on the Nacelle so the gear alignment could be just out of the reverse gate if you know what I mean. If you find it then adjustment under the dash is required.
If you don't find reverse with the gear lever try going to the side of the gear box where the gear change lever is. Disconnect the cable and with the assistance of a friend sat in the drivers seat with their foot on the brake move the lever up and down selecting the gears seeing if it will drop into reverse. I am lucky in that I have access to a ramp where I can get all four wheels off the ground and I can then do this by myself as I don't need to have someone stopping the car from taking off if I do find a gear. On my 1968 S Type I have an inspection hatch to get to the side of the gearbox and this lever situated on the left side of the tunnel under the carpet. Small metal cover held in place with 6 cross head screws.
If you genuinely cannot find reverse doing the above then I am afraid it is to a garage for a check and possible rebuild.

 

Also check that the gearbox oil is full.
I'm not sure what gearbox you have but if it is a DG it must be checked with the engine running and Drive selected.
I endorse CASS's suggestions as many gearbox problems in automatic MK1 and MK2s originated from gearshift linkage problems.

 

If its a DG 250 trans -with reverse to the far right- you may need to try pulling the shift lever more firmly down, also showing a need for adjustment. Been there....

 

Thank you all for your help.