We have had some really bad weather lately so I find myself in 4wd a lot. Today I noticed a vibration over 50mph. When I went into 2 hi it went away. My Jeep is a 2015 with metal cloak 3.5. I also have an Adams 1310 front shaft that I had on my last jeep without a problem. It has been good for the first 7000 on the 2015 and doesn't seem to cause a problem unless I am in 4 HI.

What else could it be?

 

Id check all bolts on the front end (track bar, drag link, tie rod, control arms) and inspect the front u-joints in the axle shaft

 

Mo' Info...

No vibrations in 4hi until today? Or you haven't tried 4hi in a while and it could be some other mod that is causing it?

3.5" MC coils, what is the caster? You have rechecked torque on the pinion nut? Does adams balance with the yokes? Could be that unbolting the driveshaft, spinning 180, and rebolting could help. Or having it balanced.

 

Thank you both for the quick response. I can't say I felt the vibration before today or if it was there, it is a lot worse. Would the drive shaft vibration go away in 2wd? That's the part that I find puzzling. I don't know if Adams balance with the yoke but I haven't had any issues with the driveshaft over the last 3 years and I was in 4wd almost all last winter. When I switched it to this Jeep, I took a lot of time to re-grease the shaft and give it a close look over.

I'm trying to think of things that behave differently when the 4wd is engaged but I'm open to all ideas.

 

Remove the driveshaft and go for a drive. That should confirm or eliminate. If the vibe goes away, double check the torque, install it rotated 180 from where it is now, and maybe have the balance checked.

If the vibe doesn't go away, maybe a ujoint? Was it regeared? Maybe they messed up and installed different ratios? (don't laugh, there was a thread on this last year)

 

sorry if this is a silly question, do you suggest I take out the shaft and put it in 4wd? It drives great with the shaft in when I'm in 2wd now. I didn't re-gear. The axle is still totally stock.

 

Oh don't do that....

 

Yes, take a drive in 4wd with the front drive shaft removed.

 

lol, gothcha. I wasn't in synch with the "No vibes in 2wd / vibes in 4wd". If it's not the ujoints or something, it still wouldn't hurt to check the pinion nut and driveshaft balance, just in case going from freespin (2wd) to powered (4wd) is causing the vibes.