I just bought a nice solid 1977 4x4 150 and noticed some viration on the highway coming home. I am not sure if this is a 1. tire, 2. drive shaft, or 3. the front axles not disengaging completely (my hunch)

The friend I bought it from JUST installed a new U-joint behind the front drivers wheel and another one on the main drive shaft (front). When I asked hime to demonstrate that the 4x4 worked, he spun all for tires but not after noticing that he put the hub back together a little wrong (the Free and Lock words were not lining up with the sellector) He made some adjustments with a srewdriver and I was off on my way.

Correct me if I am wrong BUT if I am in 2H and the hubs are set to "Free" the front U-joints should not turn right? Any tips on testing this? IF it were to be remaining Locked, what could the issue be? Would this call vibration at highway speeds?

Thanks

Ian

 

You are correct, if the transfer case is in 2wd and the hubs are set to "free" the front u-joints should not be turning at all. This won't necessarily cause a vibration though unless there is a problem with those u-joints, for example my 77 was originally full time four wheel drive so the front axles were always spinning. It will cause more wear and tear on your front end and kill your gas milage but shouldn't vibrate. Someone who is an experianced mechanic can probably tell you where the vibration is coming from just by driving the truck, its kind of hard to diagnose over the internet.

One possibility though is that the with the hubs not being properly installed the wheel bearings may not have been tightened the way they need to be. Get someone who knows what there doing to check out the hubs and go from there.

-Jon

 

Thanks man, I DID also notice that my radial arm bushings were pretty well worn out. Could that cause the bucking vibration or what?

 

Usually worn radius arm bushings will cause the truck to wander, like if you were driving on a real windy day.

-Jon