Thanks for the info!The instructions for disassembly are in the Factory Service Manual along with an exploded view. It is best if you look at them as there are a few tricks to disassembly.
Go to myflyertrains.org, then Gilbert paper, then click on the manual. Go to the section "Accessories and Action Cars", the 977 starts on page 23.
To remove the pins first heat them a little with the tip of a soldering iron to very slightly soften the plastic of the caboose shell.
Everything is back together and works fine. I ordered a 4amp full bridge rectifier 50 volts from radio shack online to stop the buzzing noise. It was a little hard bending the tabs on end fence rails on the body without breaking some thing else but I got it. The myflyertrains .org had all the info to do the job.Let us know how it all works when you are done.