Hey fellas i got a '77 F-100 that runs great but the tranny will change gears on its own. If its in park sometimes it will just drop into reverse, in drive if I floor it it drops from drive to 2nd. I think the problem my be in the coulum but I need some help with how to find out for sure. Thanks.

 

There is a metal detent on the upper flange (the round metal part directly below the wheel). If it's worn, the lever will not seat properly, and flop around. Other causes..bad shift tube, worn shift lever, and at the bottom of the column under the hood, worn or missing shift selector lever bushing. This is the arm where the linkage from the transmission attaches.

 

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