my 2002 f-150 has had this cab drone noise for a while now and its getting louder, its coming from the rearend best i can tell.
so i crawled under it today to look at the universal joints when i grabbed the drive shaft i could move the part coming out of the rear of the differential and it had about 1/16 of play up and down and side to side. is there a bearing on that side of the rearend shaft?
i looked at my rearend grease and it was gray with what felt like meatl particals in it very small pieces. truck has 62,000 on it.
does your truck rear ends have this play???
the noise only does it at 40-50 mph then gets quit again.
and only during acceleration. any ideas?

 

pinion bearings?? are they hard to change myself??

 

Not so hard to change, but very hard for anyone the first time without the proper tools (pinion depth setting gauges etc). If you do it wrong the shop will do it again. You can search here or at www.fullsizebronco.com and get detailed instructions with pictures. If you have metal in the fluid all bearings may need changed along with any worn parts..

 

i tighten the pinion nut and all the slack came out, i'll change fluid this weekend with reports on what i find. so far so good. no more roaring.

 

Um, you do realize that this adjusts pinion bearing preload, a very critical figure for a long and happy life from those bearings, right?

 

i tighten it till the pinion slack up and down was gone, then i made sure that the companion nut was still able to turn freely after i tighten the nut,, i really didn't turn the nut but about 1/2 a turn, it was a 27mm nut.
do you think that'll work?? opions please

 

I doubt it'll work for very long. Pinion bearing preload is a touchy thing. Too little, and you'll get a gear whine on coast down, too much and you'll get a whine on accel. Either case is not good for the pinion bearings; incorrect pinion bearing preload can destroy the bearings in short order.

Depending on how loud the noise is, at this point you may want to consider having the axle disassembled, inspected and having any/all bearings replaced as needed. Axle noise is one of those things you can't really tell much about until you've taken the axle apart, seeing what all is broke.

 

I had the same problem on my 89 F150. The pinion nut would come loose all the time. So I remove the drive shafts and had them rebalanced again. Installed a new seal on the front since I had the nut/yoke off. I just tighten the nut down until there wasn't anymore play and it's been over 150,000 miles on it with no problems. Even tow a boat out to Vegas from Texas and back. Now the truck has a quarter of million miles on it and it's still going strong except for the AC.

 

Pinion nuts are supposed to be replaced whenever they're removed. They're got thread lock on them from the factory, and when the pinion bearing preload is set, they're tightened to probably somewhere north of 300 ft/lbs.

If they constantly loosen, you've got other problems you need to address first.

 

that nut is Super tight , every bit of 300#
i'm 235 lbs. 6'2" TALL AND I USED 1/2 INCH DRIVE WITH A CHEETER PIPE AND DIDN'T GET BUT 1/2 INCH TURN ON NUT!!!! super tight!!!!!!

 

Very common:

https://www.f150online.com/forums/sh...d.php?t=248830

 

i'm changing the fluid in the morning, i'll look at all bearing and maybe post some pics . i 'm using lubramatic 75w140 fully syn, oil.
does it hold 3.5 or 4 qts??

 

On mine it's 250 ft lbs and with shims it's pretty hard to mess things up. Now if there was a crush sleeve then that would be a different story.