I've lurked around here looking for solutions and finally joined to see if folks here could offer suggestions. I'll try and be brief in describing this prob.

Bought my '06 250 SD/LB/FX4 20in Alcoa wheels w/snow plow prep brand new. After about 5k miles I hooked it up to pull a bobcat and noticed a mild shudder/vibration in my seat at the shift into 2nd only under moderate-heavy accel. Since I was only pulling mayb once a year, didn't think much of it.

Now I have 52k miles on her w/an aluminum dump insert and a 8' Vplow thats been on for the last 2yrs. About a 1k miles ago I started getting a(what the dealer described as a "droning" sound" coming from the rear from exactly 52-64mph. The truck went to this dealership to replace the frnt axle rubber dust seals as 1 was torn and while they had it, to perform a LOF and frnt diff fluid change along w/other fluid changes that didn't get done 4 lack of time. I get the truck back and have a shudder felt in seat and steering wheel from 1st-3rd at a 2200-3000 rpm acceleration and the "droning" sound, and now felt, from 55-60. I took it back the next day and told them somethings not right now, so they go on a test drive w/me n the service writer contributes the vibration at 55mph to tire balance and claims not to feel the shudder when shifting. They pull the rear tires and the shop that installed the tires 4 days prior, had them 2oz out of balance, on what turned out to b all 4 tires. Dealer rebalanced tires and that lessened the 55mph drone but it's still there so they checked the pinion and suggested the pinion bearing might be going bad.

I had another appointment to finish the fluids being changed(transfer case, rear diff) and since they were replacing the pinion gear seal and the rear backing plates, they would inspect all the bearings in the rear end for pitting and/or wear. Transfer case fluid was changed and called and said that they wouldn't be able to get 2 the rear axle stuff and what was going to b $1110 4 for the backing plate repair if the bearings were bad would then be $2100.

When I p/u the truck, I hooked up the plow and the acceleration shudder is still there and a lil worse, but the droning/vibration at 55-60mph is ridiculous now.

With all that said my question is, A: how is the acceleration shudder related to the rear, that can b felt in the steering wheel, that wasn't there b4 they tore the front axles out and B: would the TSB about shimming the carrier bearing remedy this, especially w/the plow on.

Sorry for the LOOOOOOng drawn out post but I figure too much info. was better than not enuff. I would greatly appreciate any help/knowledge/suggestions that anyone could share and Thank You in advance.

 

TeeK75062, welcome to FTE.

Yes, you need to follow the TSB for the shudder. It is related to the drive line angle. Any load, even a plow on the front the front axle, can make it worse.

The drone may or may not be related to the shudder, so I would fix the shudder first, then go after the droning sound. That could be tires, a pinion bearing, or also the carrier bearing.

 

Thank you redford, and I really appreciate the wealth of info on here. I'm going to try shimming the carrier bearing today. What I'm really wondering is why this shifting shudder would have started AFTER they took the front axles out, changed the front diff fluid and did a trans flush(all done in 1st visit, then the shudder started)? How would any of these services affect the driveline angles?

 

It wouldn't affect the rear angle. It may just be coincidence that the shudder happened after the service, unless for some reason the needed to loosen the carrier bearing.

 

Checked the torque of carrier bearing bolts and they were at spec. Could there have been something assembled incorrectly that could cause this? I greased the u-joint at the axle-wheel connection and without the plow on and it help for about a mile. Could this u-joint be going bad? Could the shudder b from wheel bearing going bad? The dealer tells me that the axle end bearing is located in the 4x4 lock assembly which is a $270 part and tells me it's not a serviceable part. Much cheaper than the $900 thought for the rear that wasn't even touched when the shudder began. Could it be a trans prob starting? Possibly wrong fluid? I'm just trying to diagnose this problem instead of doing the typical dealer thing and just start replacing stuff. Problem here is it 20 outside and I don't have the time, tools or funds to perform most of this stuff