The engine had been running, not sure where there is a reserve vacuum tank though.
It may have a vacuum leak, because, thinking about it, I am not sure the vacuum tube under the dash for the speedo adapter is plugged. I think it may be open. What you are saying is, the vacuum-shifted rear needs vacuum to keep it in gear? (or at least in high gear?) I am not 100% sure whether it was in low or hi. ONe of the vacuum lines was off the truck when I got it and I noticed the metal tube on the rear was full of mud! I cleaned it out with an awl and stuck the vacuum line back on it. I will be checking it out some more. Thanks.
I think this is the vacuum tank on my truck. It's bolted outside the passenger frame rail near the tranny.
Vacuum tank location Vacuum tank close-up
