1993 Pontiac Transport Transmission Problems

Hello,
I have a 1993 Pontiac Transport 3.1L V6 which runs fine and shifts through the gears fine without slippage. When trying to go into reverse it doesnt move or make any sound as if it is even trying to engage the transmission. It is as though it is in Neutral.

Am I facing a transmission overhaul or is there something simpler and less costly to repairing this?
Thanks,
Gary

iF ALL FORWARD GEARS APPLY NORMALLY, it points to the lo-reverse clutch. It would also mean that if you start in 1st gear - transmission range 1 - accelerate then release gas pedal: you should have no engine braking, that is when you release throttle, it would coast like in Neutral.. check it and report what you find....
Causes in that case can be, according to GM's '93 Transport service manual
- lo/reverse clutch leaking seals
-lo/reverse piping o-ring damaged
lo/reverse clutch burned plates
manual valve has fallen out retained clip.
....
...I've driven my '79 Ford 1 year without reverse.....:lol2:

p.s. The piping and o-rings and seals are all "serviceable" items accessible from under the car after oil pan and oil strainer are removed.