Another "vibration" thread

[DesertK20]

The double cardan on my front driveshaft made a ton of noise so I took it out, drove the truck around in 2wd until I received the parts.  I put everything back together with 3 new u-joints and also rebuilt the centering yoke.  Everything went together good but at about 45 mph I can hear this hum now coming from the front end, and also my 4wd shifter is vibrating a little.  The cardan joint was pretty tight but not binding. 

I have a sinking feeling that I may have messed up a needle bearing in one of the u-joints, I put it all together with a 6" vice, lubricated accordingly. 

Also when the shaft was out I installed 6" lift springs all around, 35" tires, and it drove fine without the front driveshaft.  I really don't want to pull it all back apart.....

[bake74]

      Sometimes the only way to find out what is wrong is to pull it apart again and recheck everything.

[Sartobuilt]

Check for binding in the cardan joint. There are ears that need to be clearanced. Set parking brake put t case in neutral, hubs unlocked. Spin the front shaft you should see what i'm talking about.

[DesertK20]

Check for binding in the cardan joint. There are ears that need to be clearanced. Set parking brake put t case in neutral, hubs unlocked. Spin the front shaft you should see what i'm talking about.

I saw some write-ups on what to grind and I thought I hit it all, definitely worth a check.  Did you lower your Tcase?

Bake74, you're not supposed to tell me what I don't want to hear....

[pholliday1]

I'm not sure if your front drive shaft has a blind spline or not? I'm thinking no and if you "pulled everything apart" the front u joint may not be in phase with the cardan joint. And lastly with the front lift installed the slip splines may not be engaged enough to providing proper support. It may not hurt to take it to a shop and have it balanced?

[DesertK20]

I'm not sure if your front drive shaft has a blind spline or not? I'm thinking no and if you "pulled everything apart" the front u joint may not be in phase with the cardan joint. And lastly with the front lift installed the slip splines may not be engaged enough to providing proper support. It may not hurt to take it to a shop and have it balanced?

I did not know this.  I guess it's time to pull it back out.  Ugh, live and learn, appreciate the help everyone.

[pholliday1]

I would do some research on driveline angles, phasing of u joints and the repercussions of lower transfer cases and creating more drive line problems. U joints are only made to operate at certain angle and by using a magnetic angle finder you can start to determine your driveshaft angles. There's an art to getting it correct.

[bake74]

     Can you take a pic and post first so we can see what you are talking about ?

[Blazin]

With a 6" lift your splines are probably not far enough together. If they are showing at all the shaft is extended to far. What will happen is as the shaft spins it will create a whip effect where the shaft, & yoke come together. This could cause a vibration, or humming sound.

[DesertK20]

With a 6" lift your splines are probably not far enough together. If they are showing at all the shaft is extended to far. What will happen is as the shaft spins it will create a whip effect where the shaft, & yoke come together. This could cause a vibration, or humming sound.

Yeah after looking at everything, double checking and such it appears this is probably the culprit.  Appreciate all of the input folks, going to start looking into driveshafts this fall.