I have a Trane XR80 gas furnace that started to act up recently. I
narrowed down to the gas valve. It was getting 24V, but not opening. I
lightly tapped it with a hammer, and it started working again.

Are these valves similiar to gas dryer valves? I had a problem with my
dryer one time, and just replaced the solenoids, and was fixed. Can I
do the same with a furnace gas valve? This is the gas valve on my
furnace now:

http://compare.ebay.com/like/1806587...pes& var=sbar

There is a plastic cover on it which can be removed. If I remove it,
will I find the solenoids?