Bad Vibrations

I recently replaced my tires and was told I had a bad bearing in the rear end. Since these are pressed bearings, I took it to my mechanic who replaced the right rear axle assembly. I also replaced the shocks on the rear end and the front struts.

last weekend I took the truck on a fishing trip and noticed a vibration. I had just filled the tank and thought I may have gotten bad gas. There was no hesitation when not in drive. I recently had it in 4 high and thought maybe it hadn’t completely disengaged. I slowed the truck and switched to 4 high, it engaged and disengaged twice.

then I thought maybe a rock in the drivetrain. So from a stop, I stepped on it to see if quick acceleration changed anything. I felt a strong vibration and could hear a whine/roar.

the weather was very hot so maybe it had something to do with that, but then I let the truck cool down, the outside temperature was 68. I took for a short drive. Everything was fine until I accelerated and felt the vibration return. This time I never got above 30 mph.

I’m curious what it could be. One thought is the left rear axle assembly when bad. The other is since the right rear axle assembly was replaced, perhaps they didn’t fit it correctly into the gears and my rear end is going out.

truck runs fine. I don’t want to drop several grand in fixes. Any suggestions? Plus it’s the 4th of July and I want to go to the river!!

 

Have you checked the U-Joints and carrier bearing? If not that's where I'd start looking.

 

I replaced the u joint and the carrier bearing is fine. It took care of the horrible vibrations but there is a slight vibration continuing. My tachometer hits 2k at about 64 mph. Prior to problem it tached 2k at 70mph.

 

Change of tire size?

 

No

 

Ok, I wanted to give an update. I have replaced all tires, both front CV axles, front and rear shocks, u-joints and I have lubed the u joints again. I took it on fishing trip towing my camper over the weekend, no problems but I could still feel the vibrations. I took it on a 200 mile trip in 98 degree weather today, it did fine on the drive down when it was in the 80s. Driving back with the cruise control set at 70 mph and pulling a steep hill, it kicked down to 4th gear at about 3000 rpms, I heard a loud hum and could feel the vibration again. I left the sliding back glass open so I could hear.

I have had the truck for 5 years and drive it regularly. This issue is new this month.

Sorry for putting out dumb stuff, but I am not a mechanic. Just trying to save some money.

Carrier bearing?

 

Just tossing out ideas, did you check all fluids? (Rear diff, transmission, etc)

 

Yes, I’ve checked all of those and i took it to my mechanic who said he cannot feel it. The kid and I are normal drivers and we both feel it. I’m beginning to wonder if it is an exhaust leak and not mechanical