Sounds like a time bomb

[ksjh1316]

Just noticed today a ticking sound when the gear is engaged and the truck is moving. Out of gear there is no noise at all kind of hard to check this while moving down the road by myself. Engine is a 292 and not sure on trans other than 4 speed man any sugestions as to where to start looking is appreciated. Also I know in my British cars Slick 50 and other similar products were bad does the same hold true for these trucks.