Yep, yep... replaced the front differential and now I have a subtle vibration around 45 mph. The driveshaft is used but upon visual inspection looked great. What about this new differential could be causing this? I checked the flange for play and didn't find any, but I suppose I could check again too by some other method. IDK... that seems like the only thing that could cause this yeah? Play in the flange?

 

A drive line shop can balance the driveshaft with weights. Not sure the cost, but then you could rule out the drive shaft being unbalanced.

 

I removed the driveshaft and drove it around for a couple weeks and noticed the problem completely went away. It was already a Tom Woods driveshaft with only a few thousand miles, but nevertheless, I called TW and told them about the problem. They offered to build me a custom length driveshaft in exchange for returning and keeping the “old”one. That arrived last week, I installed it, and drove it around for a week and now feel Iike I have enough data points to confidently say the problem still exists.

So we can rule out the driveshaft.

 

Normally, a differential will make a lot of strange noises...before it ever gets to the point of transmitting a vibration. Are you getting any defined noises along with the vibration? And, l'm not trying to knock TW shafts...but didn't we just go through this with another member here...he also got a couple different shafts from him and both vibrated at certain speeds? Pretty sure l remember something to this affect.

What does the play feel like on transfer case output flange, for front shaft? If flange feels normal on differential, l guess you could drop the fluid and look for anything unusual, shavings or material.

 

The differential is absolutely silent, so I’m doubting anything is wrong with it. And again, it’s a new used unit, but I did inspect before installing it and it looked and functioned perfectly. I’ll check for play in the flange this weekend.

Interesting thing about the TW shaft being about of balance that you mentioned... this new shaft didn’t resolve the issue that I experienced with the old shaft, but it did diminish it slightly. Like, it’s certainly less of a vibration than before.

 

Before throwing money at it, try to balance with the two screw hose clamp technique. Place and tighten a screw clamp on the drive shaft, place a second one beside and place the screw opposite side of the other so they cancel each other out. Then rotate one a small amount. It should decrease, or increase, the imbalance. If better, move a little more until balanced. If worse, go back to direct opposite and move in other direction until balanced. If for some reason you need more weight to balance add two more clamps and move as needed.

 

Follow up: I took the driveshaft out and checked the differential flange bolt and the transfer case flange nut for proper torque. Differential was good but the TC took a couple cranks of the torque wrench. So far that solved it ¯\_(ツ)_/¯

 

Well, hopefully that was it, loose output flange nut. A couple "cranks" would be severely loose, crank = one revolution. Anyhow. Yeah, "sweet-spot" vibrations are hard to find sometimes. Since they usually only appear at one distinct time. When the output shaft and all internal parts of the transfer case are producing torque to move flanges, driveshafts, differentials, wheels...it's loaded up with resistance/pressures...so all loose/sloppy areas are forced tight...but...when you hit that "sweet-spot" where torque balances out and pressures are removed...all of or any loose or out of balance areas rear their ugly head. But, as you've found out...it's just a matter of elimination and searching to find the culprit.

 

Sad to report, the vibration has not in fact changed. Have driven over 500 miles since last post and I think it may be worsening.

I notice it’s only transmitting through the steering wheel. When it’s occurring, if I let go of the wheel, I can’t feel it at all. Happens at its worst between 30-40mph. Overall, the ride is getting more rough at all speeds.

The tires are about 7 years old but have a ton of tread left. Should I not rule these out?

 

Have you tried rotating the tires to see if things change...