300tdi bouncing + knocking

im having a couple of issues with my 300tdi its bouncing back and forth when i try and maintain speed only when the throttle is slightly applied and if i put my foot on and off on and off the accelerator quickly and if a change gear quickly it bangs from underneath could this be my front prop?? front diff?? its just annoying my now

have you got underneath and waggled the front prop at the spline joint and both UJ's, what state is the donut in on the back prop?

you gotta expect a little play in the drive train, but if you can turn your props more than about an 8th to 1/4 of a turn then you need to investigate whats worn out.

there could also be a fueling problem, have you cleaned out the sedimentor?

i can turn the front prop about 1/4 of a turn but the back prop hardly moves at all this might seem stupid but is the sedimentor next to the fuel filter sorry first discovery

back prop wont move a mm if you got your handbrake on!

sedimentor is inside the chassis, above the back axle, use an 11mm open ended spanner on the bolt on the very top center, you'll have to do this blind and by feel, this bolt runs vertical and holds the bottm part of the bowl on... drop the bowl off, if you got a jellyfish living in there then chances are your engine will run lumpy under accelleration.

prepare for a face full of diesel dont get your face right under it, and cup the bowl into an ice cream tub or the like as it comes off.

once cleaned and refitted, start the engine, but it will stutter while it the sedimentor refills, just keep the throttle on as best you can untill it gets back up to smooth running or crank it if it stalls.

Worth getting new rubber seals for it as well-they can disintegrate/dry out