66impala, welcome to the stovebolt forums. Start a new topic of your own and you'll get better responses. Your transmission is a hydramatic. Yes it's rare. Park it in reverse. It has a locking pin when the engine isn't running. For more info check out the old GMC website.


"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.