1999 F250 crewcab lariat 4x4 diesel 175000 miles
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I have a vibration in the front end when in 4x4, most noticible when decelarating from 40 mph to 20 mph in 4x4.
Thought it was the u-joints.. replaced all three u joints on front driveline... was not the u-joints, or did not fix the problem.. although one was bad.
Put the truck on a lift and found out that my lower left ball joint was shot.. so i pulled the axles and pressed in all new ball joints, top and bottom both sides..had to replace both inner and outer axle seals both sides..repacked the front hubs the best i could ,with the non servicable front hubs. tightened things up but still have the nasty vibration.
Now I am thinking I have a unbalanced driveline.. but i am in a remote part of Alaska with no shop to balance the driveline.. Wonder if any one has tried to re-phase the driveline by twisting it 45-180 degrees or balance with hose clamps any techniques other than trial and error??? ideas...

Late.............

 

What about the u-joints on the axle itself?

 

The u-joints on the axle appeared to be in great condition.. nice and tight.

 

It probably isn't it now that I think about it. I assume that the vibration is occuring while going straight ahead, no need for the ujoints to bend, bind, or make vibration.

When you had the wheels apart were you able to swivel them around freely?

 

Kwikordead.. thanks for the input... This has me stumped..

when i had the wheels apart and the axles out the u joints swiveled around free but not sloppy.... The front most u-joint on the driveline was bad... missing all the needle bearings in one cup... thought i found the problem...but nota.. so i repaced the other two u-joints on the front driveline.... to no avail....

then the rest of the front end deal....

so the latest road test..

4x4 with hubs locked........significant vibration 28-49 mph
hubs locked, 4x4 disengaged.........much milder vibration at the same speeds
4x4 engaged, hub disengaged.... no vibration at all

all going straight down the highway

This makes me question my driveline balance theory??

I don't know

 

Hmmm, well you're driveline is going to be spinning under all three of those settings. So if it were out of balance it would feel the same no matter what. The key difference that I am seeing is the amount of torque load that is being put on the front drive assembly. How about a problem with the front diff?

 

Check to see if you have play in the front diff pinion bearing by moving your yoke up and down. Also pull the oil plug and check the oil to see if any moisture has got inside the case if so it may have pitted your ring and pinion.

 

Did you check the small needle bearings inside the hub that the axles go through? Try pushing/pulling the axles, there shouldn't be much movement.