[jpmatrix]

There is always going be some noise from a shaft driven 4wd buggy.

But I would check the following..

If you have a brand new rw spur gear and you think it's still noisy then i would try another pinion. I have had a rw pinion and it made a horrendous noise, chànged to a hpi pinion and was fine. With regards to meshing i personally check it by eye and feel. Take out the battery and look directly in front of the meshing. I hold the spur gear and rotate it every 60deg and then rock it backwards and forwards to see if there is some backlash. You can feel it with your finger and there should a little backlash. Even though rw spur gears are machined yoi can yoi may find a little tight spot; that's why I rotate it all the round to make there is no binding / tight spot.

If you think there is still excessive noise i would check each diff and make sure they are shimmed correctly. I found that pinion to crown gear can often have binding spots. Best way to sort that out is to rotate the mid shaft and feel for any binding. If there is , use the copper shims to get the correct mesh. Also when tightening up the diff housing just nip up the 3 screws as over tightening can also cause binding.

The cvd shafts can be noisy make sure there is no play and they are lubricated.
I use the rubber boots the go over the cvd joints and i grease the inside of the boots. If they are dry this can make a right racket.

Can really think of anything.

If all the checks above fail maybe look at the motor and bearings.