If your '82 is anything like our '69 you'll find the "T" handle in the rear compartment.
Here's a few pic's ,
1st is looking through the rear access door the "T" handle is to the left of the 'faucet' knob and behind the pressure regulator hidden from view. It most likely has 2 wire bails slipped over the "T" handle, just move them sideways to lift the "T" handle to dump.
Pic 2 & 3 This is after I gutted the interior and you can see the "T" handle better.
Pic 4 is what that area looks like today, But that's another story.