Ok I need help from all of you driveline experts diagnosing a noise/vibration in my truck. Its a pulsating noise/vibration that only happens between 55 and 70. You can hear it coming from under the truck, its doesn't shake the truck at all. I haven't noticed any lack of power or performance from my truck. I do need to get my tires balanced and I'm do for balljoints, tierods, and shocks. I was going to guess it to be a u-joint. Wheel bearings felt good and the truck has new brakes.My truck has always made a slight pulsating noise at 70 mph since I bought it at 38K. Now it has 112K. Nothing seems wrong with the truck, and this has me kinda stumped. Any input? Thanks!

 

Front drive shaft u-joints, almost 100% positive on this. You have a CAD front end same as me, once over 55 mph you get a vibration, over 70 it goes away sometimes. Mine was replaced under warranty but I expect it again.

Even though your not using the front drive shaft in 2wd, for the quick shift 4x4 the shaft is moving all the time.

Replace u-joints, spicer brand are my favorite.

Good luck.

 

After work today I got under the truck and started looking at the ujoints. I found both on the rear drive shaft to be bad and one front. I'm going to replace them all, but i'm still open to suggestions.

 

u joints would be my frist thing on my to do list. get the tire balanced as well. but deffinintly take care of those balljoints and tierods as well. if one of those break on you it will do alot of damage.

 

Well I changed the rear driveshaft u-joints tonight and it made a little diiference in my problem. Now I need to do the front shaft and the of whats wrong.

 

The truck was smooth as glass. That narrowed down the search for me. The u-joints didn't really seem that bad by the usual tests.

 

Ok, update! I took off the front shaft today after work and found the very front u-joint to be bad, and on the double joint on the rear of the front shaft I found something bad too. From what I see it looks like there is a small "ball joint" in the double cardan joint. This "ball joint" is fubar and so are both u-joints. Anyone else have this joint go bad? I can get my u-joints at the parts store, but after ordering them I noticed this ball joint was bad too. Its too late to call the store now so can anyone tell me is this piece is able to be ordered easily? I'll try to get a picture of it tonight.

 

Another update. I had the driveshaft gone through by a very good driveline shop and they replaced every joint. I drove the truck around for a day or two w/o the front shaft in and I still has some noise. I install the front shaft after having it rebuilt and still have a little noise. Its not as bad as it started out to be but there it still some. I checked my hubs again, did some research on here, and found my DS front hub to be bad. So I have one that should be in monday morning along with new moog ball joints and tie rods. I would have gotten a second hub but it was hard enough to get this one.

 

I was going to wait till I did the balljoints and tie rods to do my Hub but the noise was getting worse and worse so today after I picked up my parts I installed the new hub. Took the truck for a test drive and the noise is gone. I used the P/S method to pop the hub loose. Before installing the new hub I anti-siezed the crap out of the area it sits in and the axle shaft. At least it will come apart easy when I get around to doing the balljoints and tierods. I am also going to order another one for the driverside and install it while I have everything aprat.