S10 Ignition Key & Transmission Shift'g Problem

'97 S10 ignition key won't lock & release key and transmission only has 2nd speed. Truck starts out not in low gear, engine is revved at 70 mph so it appears it's always in 2nd speed. Occasionally pulls away with good acceleration (i.e. low gear) & cruises easily at 75-80 mph (third gear) then the key will turn all the way off and can be removed. A short time later it's back to the same problem. Doesn't relate to how it's shifted in or out of Park or any other event or action I can identify. It's done this for months - any ideas?

Hello Sheepman, welcome to the forum I think you are having a problem with your steering lock. Have you checked that already?

Thanks, Jeffie, for the welcome & reply - The ignition switch operates (off & on) normally other than not going all the way off to release the key. I don't know what else to check there. I need to investigate further into any linkages between the tranny, shift lever & steering column; I was hoping someone would come back with "yeah, I had that problem, ...". Guess I'll go put it on a hoist and look underneath for any clues I haven't seen before-- anyone out there have this problem solved already?

Oh, I'm so sorry I never encountered this problem, Sheepman did you already check out the ignition device itself and searched for anything that could obstruct the proper carrying out of its total function?

Try checking 10amp fuse at main panel that feeds shift solenoids, If fuse is not hot on both sides with ignition on, then possiable bad ignition swith. Not the key and cylinder the electrical switch in column. All other things will work but no power from ign. to fuse panel for transmiision. I have fixed two trucks with this problem.

Thanks, Anthony, for your knowledgable reply. A little update on the ign sw, I had the switch replaced a while back and the problem seemed fixed for a while (started in low gear and key turned all the way off and could be removed).

Then the problem returned, it is still intermittent, usually only goes away briefly but happens occasionally. Described the problem to a mechanic and he said I had diagnosed the problem by my description but I doubt if the new switch is haywire already so I'll check out the fuse and look for bad connections on the tranny switch. I've had to revise my thinking from mechanical interlock systems to electrical solenoids which tends to date me! Thanks again for the reply and suggestion.