Subliminal

So my truck doesn't shake at all up until 65. As i hit 65, you can feel the shaking in the floorboards. As you go faster, the shaking gets worse.

The worst is when you let off the pedal a bit and it transitions between 'under power' and 'coasting'.

List of stuff that's been changed with no effect to the shakes:

Engine Mounts
Transmission
Transfer case
Tranny Mounts
U-Joints
Driveshaft

I haven't torn into the rear, but that's where I'm leaning now...everything else is new.

Grrr!

apwatson50

tires?

Subliminal

Sorry, i should have mentioned the tires are within a year old and have been properly rotated. I mean, I guess it's possible it's a balance issue...

The thing that has me thinking in a different direction is the whole transition from under power to coasting deal.

crazy clem

have you tried different height settings on your air ride system? mine gets a weird vibration if I have too much air in it while running unloaded . probably due to changed pinion angle?

Subliminal

You know, that very thing did occur to me. I actually had to drop off my core G360 to UPS freight, which is about 40 miles from here, and I went out with probably too much air in the rear bags, so when I got out there I let out about 1/2 of the air, brought it down a bit. It did...change...the vibration, but it certainly didn't make it go away.

However, as an aside, and now that I think about it, when I swapped my transmission from the auto to the stick, i also swapped crossmembers, and the truck the crossmember came from was an 89 (vs my 91.5). The crossmember that came on the truck would sit the tranny mount about 1-2 inches lower than the crossmember that's currently in there.

At any rate, I've got a few tricks up my sleeve for the whole pinion angle thing, and I think that's definitely a possiblity.

crazy clem

trans mount height would make a difference for sure.good luck

Subliminal

Well, my plan at the moment is to swap the big rubber washers to the top and the smaller to the bottom, which should lower it about 1/2 inch. But I wish there was more I could do. I wish I still had the other crossbrace...grrr!

simplysmn

steering stablizer ???

GIT-R-DONE

Believe it or not, I have the exact same thing with mine. One of the biggest things that helped ....some....was changing out my transfer case. The one I put in was used as well, but was better. I bet it has something to do with the bearings in the X-case.

I also had: New front shaft, new Trans mounts, new U joints rear shaft, brakes all the way around, new tires. I am leaning more towards the axle joint in my right front as its about the only thing I havent replaced.

I just put in 700 lbs of sand for traction for this winter, it smoothed out the ride some and the vibration isnt quite as bad, but is definately still there.

alex211

Make sure your t-case output angle is the same as the pinion angle on the rear diff.

Changing the angle of the drivetrain with different mounts will change the driveline angles and cause a vibration from mild to wild depending on how far it's off.

dzl_damon

I've been doing a lot of research on gears since I had to emergency rebuild my spider gears which decided to explode last week! Anyway, lining up your pinon to your ring gear is such a tedious process, that most people don't bother when they put it back together.... that includes me! There are shims up the ying yang and you have to put a light paint on the gears, rotate it, and analyze how the gears meshed together to see how you must adjust it further.

Reading further into other forums, some guys complain of vibration issues and noises if not done right.

I assume your regular cab truck has no centerbearing, correct?

Also, how are your front differential u joints? I know it makes no sense, but I've been told some vibrations can come from there even if they are not locked in!

NJTman

Three points to mention.

My Toyota pickup had the same problem. Vibration from under the seat.

Took my driveshaft out to a balancing / driveshaft shop up in north NJ. Balanced the shaft, and ..... wallah... No change.


Took the shaft back out and brought it to a guy in farmingdale... Mr. Driveshaft. He re-balanced the balance the guy did from up north.

Perfect. Never had another vibration under my seat.

My Dodge:


I have the xtended cab, and I had a mean vibration as well.

Changed out the carrier bearing, and per the TSB I found someone here posted about the update with the 1/2" spacers for the carrier bearing, I've had no vibrations whatsoever.

Not Mine:
My niece has an 09 crew cab with bad vibrations. Turns out to be bad belts in NEW tires.

Go figure.

Can you borrow a set of tires to switch out to for a "temp ride ". I'd be more than willing to let you borrow my summer tires for the ride.. I have my winter mudders on now, and my summer mini tires never gave me an ounce of vibration.

You're more than welcome.

T.

pulltilbroke

How are the Yokes?

1990

I've got a vibration in third gear just at about 1100-1300 RPM as a slow down to a stop.

Subliminal

Damon, Yeah, I have never tore into a rear, so I'm a little mystified by the whole thing.

NJTman, I might take you up on that...and thanks for the offer!

Pulltilbroke, The rear yoke is brand new, the driveshaft is brand new, the u joints are brand new...the front yoke is not new, but it looked ok...although I'll be honest, I didn't spend too much time looking at it. That's something else to check...thank you!