bad pinion bearing in differential?

Messages
1
Location
oregon
Hi all, My 2000 f250 4x4 V10 5spd manual with LSD and 63k mi has an intermitant but very strong vibration like a shuddering, growling, rumbling in 2WD. The 1st time it only lasted about 1 second. It had been making a swooshing noise that sounded like front left wheel bearing for several thousand miles before this, so i replaced bearing assembly even though it turned smoothly. After that, It still made the exact same swooshing noise and after a couple miles at 45mph, it had the strong vibration/shudder that lasted about 3 seconds. I stopped and locked the hubs manually. The vibration happened again in a couple miles, so seems like it's not the needle bearings in front stub shafts or locking hubs. On that last occurence, the vibe went on for 5 seconds, felt the same with clutch in, and went away only after truck slowed down to nearly a stop. I've driven it about 6 mi total since the 1st occurance. Front right Wheel bearings feel smooth. I unbolted the driveshaft support bearing and it spins smoothly. The front u-joint maybe had a tiny bit of play, all bolts tight. I didn't check the nuts for yokes, but it didn't look like yokes had any play. Drive shaft slip joint moves smoothly. No up-down play at pinion shaft input into rear diff and output from transfer case. Rear diff oil was full with a little bit of silvery sludge on the magnetic filler plug, maybe 1/10 of a cc, no metals slivers or chunks. I raised the rear wheels and ran 5th gear 2WD at idle (~30mph) and touched a 4' listening stick to the drivetrain components. The only odd sounds were from the rear differential. It sounded like a bad bearing with random crunches and thuds mixed in with the normal whirring. Crunches and thuds were loudest at front of diff housing. I blocked one wheel and repeated in 3rd gear. You could hear noise like gears meshing (noisey spider gears? maybe was LSD clutches?). The differential was warm after 5-10 minutes, with the hotest area being about 3" from the front of diff, just before the housing widens. So, i suspect the pinion bearing is bad and the intermittant shudder is the bearing race spining in the case when bearing siezes. Any other potential causes to check before i take it to a shop? Can anybody recommend a repair shop around Beaverton or Hillsboro Oregon? Need a quick fix as we are moving to a new house. thanks,alex
 
Messages
9,109
Location
Marshfield , MA
Could it be a chattering clutch in the rear end. I would drain the diffs and replace with a good lube that specifically says it is used for LSD fills. If it says "OK for top offs" keep looking. This is the only place I use synth lube - LSDs
 
Messages
14,736
Location
Central NY
Having had two failed pinion bearings - It's a constant vibration that gets worse with speed. At first, you'll be able to "hear" it, then it will get bad enough that you'll be able to feel it in the seats (rear) or floor (front). Usually rear pinion bearings will cause a howling on acceleration / deceleration until they get bad and start to vibrate.
 
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