[70gmcjimmy]

My GMC is a '55 2nd so I can't be sure what is the same in a '59 but I am pretty sure the instrument cluster Orrie shows above isn't the same since it is a Chevy. Mine does not have a generator light so there may not be anything the same. There are 6 phillips head screws holding in the GMC cluster which is in 2 halves. The oil pressure line can limit how far you can pull it out as well as the speedometer cable. Here are a couple pics when I had my cluster out for rebuilding.

You can see 5 of the six screws in the first pic. The other one is in the center low but the steering wheel is blocking it.

The next two pics are what each half looks like removed. In my truck the green one is the turn signal indicator and is the one below the clock. The lamp sockets will just pull out to change the bulb but they are a bit of a struggle pulling and pushing back in as the bulbs ground through the metal housings.

The last pic is the cluster in a '58 or '59 GMC in a local scrapyard and you can see that this one is about the same as mine, so maybe yours too.