VTX1800N1

I just recently had the rear axle rebuilt due to a noisy pinion bearing. I replaced the stock open differential with an Eaton TrueTrac. All the bearings and seals were replaced with a Timken kit. The wheel bearings were replaced with repair wheel bearings that move the bearing contact surfaces on the axle shafts. The only internal parts that were reused were the ring and pinion, axle shafts, shims, and ABS tone ring. I had a shop do the work since setting up a ring and pinion is not something I'm familiar with.

As soon as I got the truck back I noticed a vibration that feels exactly like a wheel out of balance. I had old P rated tires on the truck that were almost worn out. I thought it might be a tire balance issue. I replaced the tires with some Goodyear LT tires. The vibration was exactly the same. I had the shop recheck the balance and still had the vibration. I took it back to the shop that did the rear axle and they eliminated the brakes (all new calipers, pads, rotors, and parking brakes).

The driveshaft is getting replaced because the slip yoke has some play. The front u joint on the driveshaft is also just now showing signs of play. I wouldn't think that this type of vibration would come from the driveshaft, but at this point I'm at a loss to explain where it's coming from.

I can start to feel the vibration at 50 MPH and it gets worse the faster you go. It seems to get worse as I drive around a curve, especially to the right. Open to any ideas.

bourgeois1269

The rear axle might be slightly out of line (if that's possible) did they go back over it when you brought it back to them ?

VTX1800N1

The mechanic pulled the cover and checked the pattern again. He said it was fine. We are both stumped.

EDIT: I also had an alignment done when the new tires were mounted after the rear end was rebuilt.

VTX1800N1

The new driveshaft arrived today. Surprisingly, it eliminated probably 80% of the vibration issue. The remaining 20% I feel might be from the stiffer sidewalls of the LT tires, as it doesn't seem like a constant frequency like an out of balance tire. However, when removing the driveshaft, I found what seems like a lot of play between the pinion and ring gear. I'm going to try to post a video here.

Especial86

iTrader: (1)

They probably didn't get that pinion nut torqued 100%.
The repair bearings were a good choice for replacement, I used them too on my axle..
I'd have them give that pinion a good re-torque just to have it eliminated as a variable.

Could also check the transmission mount. If you had some worn u joints on the driveshaft, then I'd consider that too..

So how about some feedback on the tru trac.. Been procrastinating about going that route myself. Is it noisy?

VTX1800N1

I had the crush washer replaced with a crush washer elimination kit (From Yukon) also.

VTX1800N1

No noise from it whatsoever. I really like it. It wasn't cheap, though. The TrueTrac, bearing and seal rebuilt kit, and repair bearings totalled more than $900 in parts. It was $750 in labor. I drove out to the country and put one tire on the gravel shoulder and the other on pavement, floored it, and it hooked and launched. When turning right or left from a stop sign, if you are not careful, it will spin the inside tire though. You can't romp on it. I called Eaton and got confusing answers as to whether this was normal or not.

Looking forward to the snow this winter now that I have a good limited slip in the rear and new AT tires (Goodyear All Terrain Adventure w/ Kevlar LT tires). I shouldn't need 4WD near as much.

VTX1800N1

Another interesting observation: I had what felt like a low grade engine misfire every time I took off from a stop. I could just about count 3 cylinders that were misfiring; it was that specific. It only happened from a complete stop. Eventually I figured out that this was from the slip yoke binding up on the output shaft of the transfer case. If I put the truck in 4WD, this misfire feeling went away. After installing the new driveshaft (and using the special Motorcraft PTFE grease on the splines), that misfire feeling is gone completely, even in 2WD. It was such a little thing, but SO annoying feeling that every time I drove the truck. SO happy now that that problem is fixed.

VTX1800N1

Well, good news and bad news. The bad news is that the vibration is not cured. It hasn't been consistent all along, which makes it frustratingly difficult to diagnose.

The good news is that I think I found the problem. If I apply the parking brake even lightly, the vibration gets much worse. All of the parking brake components were replaced with new only a few thousand miles ago, and this problem did not exist before the axle rebuild. We are talking drum in hat rotors, shoes, springs, adjusters, and levers. I installed all of it myself and made sure all the contact points were properly greased. I'm wondering if a spring got knocked off when he removed the axles to replace the wheel bearings. Hope to get time to take it apart later today.

VTX1800N1

I've since had the rear rotors, including the parking brake surfaces, turned with no change in vibration. I'm at a loss to explain it. If I pay close attention, I can feel it at much lower speeds.

I think my next step will be to substitute one wheel at a time with the spare. I'm wondering if the dealer's wheel balancer might be defective. It feels exactly like a tire that is way out of balance.