rsm

I have read some threads on this matter. My truck has been meticulously maintain as I bought new in 05. Redid all shocks, ball joints, tie rod ends. Had the drive shaft (and balanced) replaced with new u joints and yoke. Just had Michelin ltx 2 all replaced by Michelin bc of some bum tires, all road force balanced. Truck rides smooth as silk except for this vibration on highway around 75 mph. Tranny is fine, carrier is good, clutch pacs, couple shops just threw their hands in the air and said need to replace whole rear diff. bc its the last thing they came up with. Has anyone had any of these issues? have they found anything in particular in rear diff. that they fixed instead of a replacing whole unit? I have changed all my fluids way before required service just to be ahead of problems .. just stumped.

Mod (Ret.)

Does the vibration go away higher then 75 MPH? Did it vibrate before the new tires installed?
If it happened after the tire swap, I'd suspect that one of those new tires is out of round, or one of it's inner belts has separated slightly. Have you tried rotating the front tires to the rear, and rear to front?


Seems odd that a rear end would vibrate at high speed, and not at any other speeds.

rsm

No, the tires had issue before. Had them all replaced , road force balanced by a close friend. The vibration I get you can feel through the seat and drive train. Feels like something in the rear ending like gears . I know it's weird bc it happen sound 75-80 but below that is very less noticeable. When you accelerate to that speed then let off the gas you feel it in de acceleration until it drops back to below 70. Just weird but feels like somewhere in the driveshaft to the rear.. But the shaft , u joints, yoke are all new

Martian

Check your parking brake

rsm

yeah had that fixed too. im going to take it in to see if the new drive shaft was installed correctly, balanced right, out of phase etc. running out of options at this point.

solpushcart

You might also check to see if you need to replace your leaf spring bushings.

rsm

im checking over everything next couple days but i can verify so far that everything has checked out good except they are seeing issues within rear diff. its seems to be cheaper just to buy new and replace instead of taking apart and just fixing the bearings, ring and pinion or whatever else could be wrong

Pops1742

I have the same issue at 75 and up it vibrates and I can't see anything wrong. So in your last post are you say there's a problem with your differential????

rsm

i have been through my whole truck. Has new michelins ltx that have been road balanced, new drive shaft that is balanced with new ujoints and yoke joint, been to 2 different reputable shops where i know mechanics well and have kept my truck very well serviced. they both never nailed down the exact rear diff. issue bc they didnt want to waste money labor wise digging into but just knowing that there is a issue , but both of their points were that it is easier and better to replace whole rear that comes with a warranty 3 year/100k than take apart and replace what parts are worn. it could be the ring and pinion, bearings etc. but i guess their point is i could spend up to a 1k rebuilding rear vs spending about 1300 for a whole new rear with about 2-300 in labor and have a reliable new rear.

maffrunti56

Just wanted to share since i find it relevant... This summer my truck had this same issue at 75, but also around the 45-50 mph range. Ended up dropping my drive shaft on the NYS thruway.
The bolts holding the shaft to the rear dif sheared off. Not sure if it was an unbalanced shaft or what. Just thought I'd share this