How much play should there be in a pinion?

[Lotsa_Faith]

Rotation wise, how much should the pinion of my 14 bolt rotate before it engages and starts to turn the wheels? I am getting about 90 degrees of rotation before my pinion stops when turning the driveshaft manually.

I can take a video of it tomorrow if I'm not making any sense...

 

[rksjd8420]

With a Detroit locker, you should have about 30-45 degrees. The "slop" is in the D/L and is normal. 90 degrees is excessive.

 

[4X4HIGH]

Actually, with a Detroit it is normal to have anywhere from 90-120 degrees of driveshaft rotation before the wheels want to turn (this is with the vehicle on the ground and the trans in neutral.

This is direct right from Eaton's website....

"with the vehicle on the ground and the transmission in neutral you will have 1\4 to 1\3rd of a turn of lash in the driveshaft, this is completely normal".

 

[Lotsa_Faith]

OK so I shouldn't be worried then...

I found it the other day when I was under there checking my u joints. I'm starting to slowly develop a vibration, and really thought it was going to be the U joints crapping out but they are tight, no play in them whatsoever.

The vibe comes in between accelleration and engine braking, when the drivetrain is "freewheeling". Could this be the driveshaft being out of line? I have thrown this one before, and have a CV shaft in the garage waiting to be put in, but its a tad too long so I have to add my zero rates before doing so.

 

[blazinzuk]

The rotational play is fine, do you have any in and out play in the pinion? In and out is bad.

It sounds like you just have u joints going out slowly.