40 to 44 mph to be exact. new ball joints, shocks, brakes,rotors did guzzles needle bearing and hub maintenace and it did nothing. tire pressure is good and tires were just balanced. what am i missing looking at? thanks

 

U-joints, carrier bearing, damaged or unbalanced driveshaft, harmonic dampener on rear driveshaft loose due to rubber rot.

 

Probably the carrier bearing. You can tell by pushing up on the rear drive shaft. If you have vertical movement, you've found the culprit.

Assuming it is the carrier bearing (some call it the center support bearing), I'll share a few things I learned a while back when I had to replace mine.

1. Mark the bottom side of BOTH drive shafts (spot of white paint, grinding mark, paint pencil, etc.) BEFORE removing the rear shaft with the bearing. Otherwise, you only have a 50/50 chance of getting it back correctly. They two shafts are weight balanced, and if one is 180 degrees out of sync, you'll have the same or worse vibration when it's back together.

2. The carrier bearing is installed with 300 ft-lbs of torque. I had to go to a drive shaft shop to get my old one removed and the new one installed. It only took about 10 minutes and only cost about $20.

3. The new carrier bearing is around $50 at NAPA. If you just ASK for a discount, you'll likely get a 10% discount just for asking. Works for me almost EVERY time in any parts store I go to (Advance, Autozone, O'Reilly's, Napa, etc.).

4. BEFORE you break loose a single strap on a single u-joint, AND I CANNOT STRESS THIS ENOUGH.... BEFORE you break loose a single nut... you absolutely MUST chock your wheels, and do it in BOTH directions just to be SAFE... AND lock down your parking brake. Because I overlooked this little detail, I ended up taking a ride down my driveway on my creeper when the drive shaft came loose, and while taking that little ride, I got pushed past my left foot and ended up with two broken bones in my left ankle!! Had I not been on the creeper, I would have been rolled into a knot between the rear drive shaft, pumpkin, shock brackets, and my driveway and would have more than likely not been here to offer this warning!!

5. Lesson learned from #4 above... you CANNOT stop an 8000 lb truck from underneath if it starts rolling with you under it, and you can DIE as a result!

6. Make sure you pay close attention to lessons 4 and 5 above. The value of this truth CANNOT be overstated. Nothing else matters if you get rolled into a knot between your truck and the ground!!

7. Might as well do all your u-joints while you're at it.

8. Last, but not least.....








MAKE SURE YOU USE WHEEL CHOCKS AND YOUR PARKING BRAKE BEFORE BREAKING LOOSE A SINGLE NUT!!!!

 

That is one tuff lesson to learn the hard way, glad you are ok and hopefully healing well.

Oh ya I had a 25-40 MPH vibration in the front end, mine ended up being the drivers front left tire being defective and well at 70 MPH it decided to blow, i was under an over pass at the time with border patrol he thought I was shooting at him LOL , may be worth a look see.

 

I never knew how much movement was bad. Looks like I need to change mine out. I know it moves up and down in the rubber. Would love to smooth out my freeway ride.

 

On an old 89' F-150 I had at the same issue between 50-55 MPH. The entire truck would shake and I was unable to to figure out what was causing it. At the time I was in the middle of building a rock crawler tube bed for it and the floor wasnt in it yet. I had recently replace every U-joint on the truck so I rechecked them. One strap came loose on me and the bearing cap was walking out on me. I pushed the cap back in place and tightened the strap and the vib went away

 

Excellent warning Pete. Hope you foot is better!

 

Thanks, Mike. It's still stiffer than it was before the accident, and it tends to ache a little when the humidity gets high, but the cold doesn't bother and I now get around almost like it didn't happen (aside from the stiffness). I've even played a little racquetball, and found that my being out of shape is much more of a hindrance than the ankle.

 

x2 on the steady bearing