manual hubs locked = vibration

[azaizai]

Hey guys, i've searched and searched and havent found anything quite matching my problem...maybe its just so easy, no one posted anything about it.

1997 Ranger, 4WD 4.0 OHV 5spd extended cab.

Basically when I have the hubs locked, the front end vibrates (sounds similar to a wheel bearing going bad only a bit louder (had to turn the radio up)). It starts making noise at about 15mph and gets louder from there on out. It doesnt lessen in 4WD. It doesnt change when I turn. It *does* seem to stop for a second or two when my throttle changes. So, if I accelerate rapidly for a second (as in cruising one second, then a big dip of throttle) it'll cut out for a second or two and then return. Oppositely, sometimes if I'm cruising and let the pedal rise quickly it'll stop and then return.

I packed and tightened teh bearings a month or so ago. I also had it on the rack yesterday and everything felt tight. If I turn the hubs off, no noise whatsoever.

Anywho, I appreciate ya reading this and helping me out I'm a lil new to the 4WD scene

 

[97ranger4x4]

does it sound like it is coming from the hubs, or could it possibly be your differential. have you checked your front differential fluid and your transfer case?

 

[azaizai]

ya, spent some time on it today.

The hubs, wheel bearings and u joints all shook down fine. A co-oworker of mine noticed that my right-side half shaft was out of sync (the two yokes were 180 out). I straightened that out and it reduced the vibration a little bit.

I know the dif is full of fluid, we got the ranger in june and I've been trying to get it up to speed ever since. All the fluids in every part of that truck are fresh ^^.

Only thing I need to check now is the front drive shaft (u joints, slip yoke thingy).

...but really, I think I'll just have to be a man and get out of the truck when I want to 4WD, and I guess I'll keep the speed under 15.

 

[MAKG]

It should be able to go faster than 15 MPH.

From what you describe, I'd suspect a loose pinion bearing. Grab the front end of the front driveshaft and shake it. If it moves side to side, you have a problem.

Other possibilities are front driveshaft U-joints and the transfer case front output. Since it doesn't depend on turning, I don't think it can be anything up front, EXCEPT perhaps for the little bearings inside the spindles.

Here's an idea: unlock ONE hub and stick a steel wire through the U-joint on that side to immobilize it. Then drive it around just long enough to hear if it makes the sound or if the sound changes. Then switch sides. If it is ANYTHING ahead of the front differential, this will make a difference. An alternative is to remove the front driveshaft, and try driving around with the hubs locked and transfer case in both 2WD and 4WD.