Greetings,
Here is my problem: When my hubs are locked in, I have a bad vibration on the highway, slow driving is fine. If hubs are UNLOCKED and transfer case is in 4H, no vibration. If transfer case is in 4H and hubs are LOCKED, bad vibration at high speeds.

So, I took off my front driveshaft, and tried it again....Hubs locked in, no driveshaft, results in no vibration at any speeds. So, I have ruled out axle problems.

No driveshaft and transfer case in 4H results in a strong vibration in the tcase shifter ***.

QUESTION: Would you say imbalanced driveshaft (Shaft is 1 day old from Tom Woods) or worn out bearing in transfer case front output?

I really appreciate your help! I am just not sure which one it is...
Thanks again!

 

If you are on dry pavement the four wheels are all fighting with each other and you will get vibration and wear out your clutches. You should only lock and engage 4WD when you need it or on slippery surfaces. Slippery surfaces allow your wheels to rotate at the speed each one wants to rather than trying to rotate all the same speed. This is in the manual by the way.

If I expect bad roads, I will lock my hubs and NOT engage 4wd until needed. Even with locked hubs no 4WD, I still get more road noise and rumble due to the extra mass rotating on the shafts.

Of course I don't know how bad your vibration is, so it could be something else causing it. But driving in 4WD on dry pavement is not a good thing and will wear things out and make vibrations.

Maybe try hubs unlocked, 4WD engaged and see if you get vibration. That would probably give you some clue if it is the shaft or output. I would be a little surprised if a new aftermarket shaft is out of balance, but it can happen. Also assume the bolts are torqued properly.

I am assuming your pinion angles are good and you don't have the truck jacked up hig, this can cause all sorts of issues if done improperly.

Good Luck,

Jim Henderson

 

Hubs unlocked, t-case in 4H & no vibration means the driveshaft and t-case themselves are fine.

What happens if you lock the hubs but leave it in 2H? My guess is no vibration, because you are not supposed to lock the hubs and run it in 4H on dry pavement. That's a big no-no unless you have a full time 4wd transfer case.

 

No, no, I know all that. The roads were wet and icy, that's why I had it locked in at the axle in case I needed it. With just the axle (hubs) locked in, and not the transfer case, there is a serious vibration. Putting the transfer case in 4h would stop the vibration, and shifting back to 2h would cause it to come back after a few seconds....