check the half shafts. park the car in a way that removes all drivetrain tension from the half shafts: set park brake and put tranny in neutral. then grab halfshafts and try to wiggle. they should not wiggle at all. if they do then that is a problem. could be causeing your humpa humpa sound.

tom w

btw be careful with the glow plug. you dont want that falling into the engine. you could bend a rod or hole a piston.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.