Generally when they jump out of gear it is because of a worn syncro & clutch gear and it will likely get worse. Of course that requires tear down of the trans. Good syncros are becomming hard to find. Worn U-joints and/or driveshaft center bearing can also cause a vibration which will cause it to jump out of gear. Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine