T-Maxx diffs
 

I noticed when i was cleaning my 2.5 t-maxx that the half shafts comming out of the diffs move around a little bit. I was wondeing if they were supposed to be that loose or is my diff going bad. Thanxs

T-Maxx diffs
 

You need to shim the diff a little, there should be a tiny amount of slack but not very much, if they move quite a bit, its time to break down the diffs and put a shim kit in them!!

T-Maxx diffs
 

Yeah you want to make sure your diff is fairly snug or it will eat through the bevel gears pretty quick.
Like he said there are shims that push your pinion gears and the half shafts closer to the diff gears. There shouldn't be much play at all.
Either that or one of your bearings is going bad.