truck vibrates at 35 mph in two wheel drive, but not in 4x4? (1 Viewer)

[Longhauler]

Hello,

I have been chasing a ghost in my truck. I am finishing the suspension rebuild, new rod ends, new fluids everywhere, new grease, new shocks, leaf springs, brakes, rotors, calibers, etc.
I have had it aligned and have new stock size tires on the stock rims.
I go out for a drive and at 35 mph the shaking begins and continues to max speed. It increase slightly with intensity at the high speeds, but not dramatically. When I go to brake I can feel it in the peddle. The are no noises during this just vibrations.
Then I stop and shift into 4x4 wheel drive and charge off down the road, no vibration!
My thoughts are to have the front shaft rebalanced as that is one of the only rotating items that I haven't touched.
All help is greatly appreciated.

 

[Mace]

If you have hubs, in 2wd there should not be any real DS movement. Is it a vibration or a shaking?? How bad?

 

[OSS]

Have the wheels rebalanced at a tire shop. Driving in 4WD with the hubs locked puts a s***-ton of torsional stress on the entire driveline. You can’t use its behavior as a diagnostic tool.

 

[Longhauler]

If you have hubs, in 2wd there should not be any real DS movement. Is it a vibration or a shaking?? How bad?

Vibrating not shaking. I can still read the instrument cluster. The brake peddle feels as if I have two warped rotors when applying brakes. All of this is gone when I shift into 4 wheel H.

 

[Longhauler]

Have the wheels rebalanced at a tire shop

Yes, Les Schwab did the tires, balancing and alignment. My thought is to remove the drive shaft from the front and drive it, process of elimination.

 

[dbbowen]

whats your rear pinion angle looking like after your new suspension?

 

[Longhauler]

whats your rear pinion angle looking like after your new suspension?

Stock, we have stock rims and tyres. Only thing aftermarket is the rear bumper.

 

[dbbowen]

Stock, we have stock rims and tyres. Only thing aftermarket is the rear bumper.

you didnt change the suspension at all?

 

[Longhauler]

you didnt change the suspension at all?

All stock replacements

 

[Longhauler]

JimC rebuild the dizzy and carb, had to source a head and had it rebuilt. The engine had 292k and now has stock compression

 

[John Smith]

Did you separate the driveshaft halves when they were removed from the truck? It sounds like it may be out of phase. This could be front or rear shaft that is out of phase.

 

[Godwin]

Are you driving with hubs locked but in 2wd? If hubs are locked the front axles, diff, and driveshaft will turn and that can introduce vibration if the front shaft has problems.

 

[Longhauler]

I don’t believe so, but I will check that to verify

 

[Longhauler]

Did you separate the driveshaft halves when they were removed from the truck? It sounds like it may be out of phase. This could be front or rear shaft that is out of phase.

I did the front, but not the rear. How would one check the phasing?

 

[Godwin]

I don’t believe so, but I will check that to verify

Should've been the first thing to check.

 

[Dekeman]

Inspected all the U-joints? Checked the front wheels for bearing play? Checked for a warped rotor or sticking caliper?

 

[Longhauler]

Should've been the first thing to check.

You’re right, but I have never owned a vehicle with manual hubs. Now I am informed.

 

[Longhauler]

Inspected all the U-joints? Checked the front wheels for bearing play? Checked for a warped rotor or sticking caliper?

I am going to pull the shafts and have them inspected at a local shop.

 

[Longhauler]

You’re right, but I have never owned a vehicle with manual hubs. Now I am informed.

Both in free, but pax side frozen.

 

[bcolvin]

Man, I have been down the road of chasing vibrations . I would pull the rear drive shaft and drive in 4 wheel. That will isolate front from rear. If the ride smoothed out, Then look at u joints if not completed with your overhaul. From there I would check driveline angles and then shim. My shims needed to raise my pinion in order to smooth out my OME lift. Took a bit to get that all worked out