slapping sound when cluch engaged

[weav91]

i have a 99 f250 7.3l 6 speed manual and latley ive noticed, when going up or down a hill, if i engage my cluch without applying the gas there is a loud slapping sound coming from my tranny im guessing. ujoints are fine. a friend told me that its my gears knocking back to the otherside of the tranny when all that force is realeased by applying my cluch. but this is a pretty loud slap sound and i find it hard to believe that its normal. if anyone knows where or what i should look for it would be very helpfull. thanks

[ttyR2]

There's some play in the ZF-6 I have, but the only time I hear any sort of clunk is if I hit the clutch too quickly when the drivetrain is all wound up (like when accelerating hard from a start). If you engage and release the clutch slowly, does it still make the noise?

[weav91]

no it doesnt make the noise if i engage it slowley. it just seems so slow to have it not make that sound. just gotta get used to it i guess.