With the truck in 2wd, and the hubs unlocked, I can turn the front driveshaft about 1/2 a turn in either direction and it stops. Seems like the hubs are not unlocking. And I have a vibration between 55 and 65 MPH. Naturally, thats my cruising speed.

So I guess the question is.....shouldn't the driveshaft freespin when the hubs are unlocked?? And if they are not unlocking...how hard is it to fix?? Would this be under warranty?? Medium duty truck have a 3 year unlimited mileage on the transmission. But, I don't know the warranty on the front and rearends. Any info would be appreciated.

Sounds to me you may have a hub sticking in the lock position or the weight and resistance of the axles are keeping the driveshaft from turning. I would have it looked at just to be sure.

Yea, definitely sounds like a stuck/seized hub.

i have changed out many hubs on old trucks and it wasn't hard. but i am not sure how they would be a a medium duty truck i wouldn't say it would be any harder just bigger parts

Yea, definitely sounds like a stuck/seized hub.


x2

try rocking the truck back and forth while unlocking the hubs. sometimes there is too much force on them and they don't unlock all the way.

your front d-shaft is probably giving you the vibes

just a guess though

I have driven several miles trying to get the hubs to let loose.

If I take off the allen head bolts on the hub, springs won't come flying out will they?? I would hate to try it an find myself needing to get it towed to a shop. LOL I think the last time I had a hub apart was in 1978. If I remember correctly.....it is just a splined hub with a large coiled spring. Have they changed much since then??

not sure how yours are put together, but if they are similar to the older ones (I have a D44 and D60), then you'll take the cap off (with the allen bolts), and there should be a snap ring holding the first section in. the spring in my D44 is behind the locking mechanism which is actually behind 2 different snap rings.

i don't see how they would change the design of the hubs to much it should be just like the old ones

Take a good look at your front tires. I had the same thing and it was my tires cupping. Do you rotate often? I don't because the wheels have to be removed from 4 of the tires on my dually. Now I know better.

Regards,

try removing one of the hubs and see if you can turn the axles

I have driven several miles trying to get the hubs to let loose.

If I take off the allen head bolts on the hub, springs won't come flying out will they?? I would hate to try it an find myself needing to get it towed to a shop. LOL I think the last time I had a hub apart was in 1978. If I remember correctly.....it is just a splined hub with a large coiled spring. Have they changed much since then??
Nothing should fall out unless its broken.

you should be able to take out the 6-8 bolts and remove the hub and spin the drive shaft by hand just to see if its the hub binding