my 2000 dodge ram 1500 sport is jumping when in 4x4
If your 4x4 is jumping when rounding corners then it's normal. There's no differential action between the front and rear drivelines and they're trying to spin at different speeds whenever you make a turn on not-so-slippery surfaces. If it's jumping going straight down the road - I'd look at the transfer case - but I've never heard of it.
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