First off i know this is beating a dead horse, but I just can't seem to find the right answer.

My problem is The notorious clunk when shifting or when I let the clutch out a little to fast. I get a deadly vibration at 65mph(balance needed?) and my driveshaft has a bunch of freeplay when I turn it by hand. The u-joints are fine. I think it might be the carrier bearing pre-load??? I would love some input on this, before I start tearing it apart lol... It has quite a few aftermarket items including a marlin crawler tcase. Not sure if the differential has had work done to it or not.
Thanks!

 

My truck does this going into 2nd and third. Also grinds when I go into second. I'll follow this ...

 

Define bunch of free play??

How are you checking your ujoints??

Clunks when starting out are pretty often joints.Although I had one person (blonde) that had a similar issue turns out the jack was loose in a custom bracket behind the seat.

What size tires are you running ?? Some tires just have a spot where they vibrate no matter how well balanced.

Truck or 4runner?? Mileage ??