I've been trying to track down a vibration and decided that it could be the driveshaft or a bearing. I removed the driveshaft and found that the pinion nut is loose. Once the driveshaft was out I could get some lateral play, very slight, so I just snugged the nut a little and it went away. What's my best course to follow now as I have no idea what the original torque was. It's getting cold out and my garage is gone, so I need simple as possible at least till I have a chance in a few months when it gets warm again and I can do it right.

 

that nut needs to be about as tight as you can get it then keep an eye on it, Gigger

 

Don't I have to be careful of overtightening it an crushing the collar too much?

 

the collar is crushed already from when it was put together, it takes about 150 lbs of torque to make it right

 

Tightening the pinion nut without replacing the crush sleeve will likely result in the pinion bearings going away. Also use a new pinion nut.

 

OK, so I tightened thee pinion nut to about 130lbs and it made the problem about 70% better. Now the vibration doesn't start till about 60mph and it isn't as severe. What should be the next step to go after the remainder of the problem? Is it likely in the bearing?

 

Yes because it was loose & you did not know & you drove it like that, probably the pinion bearings are bad now. Gigger

 

2005 F150 4x4 Lariat 5.4

So, I suspect my pinion nut is loose. (got the truck 3 years ago and had a complete rear diff rebuild per the ford SB due to the rear end whine... I guess the pinion nut was not torqued right at the factory) no issues for 3 years and about 25k miles. around the 3 year mark I start to hear a slight clunking coming from the rear, directly proportional to the drive shaft rpm's. No sign of leaks, fluid level is good. I just pulled the driveshaft to check the u joints and they are fine, no play at all and rotate smoothly. the collar going into the rear end has play if I shake it in any direction. That's my clunking. From what I've read, a bad bearing will be loud, but shouldn't cause play like this. So I want to check the torque on the pinion nut since I've read so much about people having them just loosen up on their own. I'm just wondering if I should go by the 8-14 inch pounds of rotational torque for used bearings? if it's significantly loose, should I tighten it until the rotational torque is in that range? Since I'm not removing anything and it's already loose, I can't mark it and count my turns... that just doesn't apply here.