Play in front axle input pinion.

[Whiteloweredhemi]

is there supposed to be any play (left/right, up/down) in the front axle input pinion? Maybe a bad bearing or it’s just loose. If it’s loose and I go to tighten it will it throw it out of spec?

 

[PaulTGarrett]

If there is any side to side play, you have problems. Either the bearing is worn or the pinion is loose or both. If you've been driving it for a while with it loose, you most likely have damaged the ring and pinion gear faces. No matter what, unless you are experienced at rebuilding differentials in your garage, you need to take it to a shop some where that can fix it.

Just "tightening it up" will do nothing but cause more problems. There are torque specs to be observed on the pinion that cannot be set with the axle shafts in. There is a crush sleeve that sets those torque specs and if it is over tightened, you will have problems.

Overall, I hate to tell ya, you have a problem that is out of the hands of most home mechanics. You need someone who knows how to rebuild an axle.