I have a vibration in my truck that feels like driving over grooved pavement. It only occurs between 5 and 15 mph. Can't feel it unless under light or no throttle. I have check all my u-joints. Feel it more in the seat of your pants than in the steering wheel. If it is doing it and I put it in 4WD, the vibration immediately stops. If I put it back in 2WD, the vibration returns. I don't hear any abnormal noises. I read on an earlier post that someone else was having this problem and it was a snap ring in the rear output shaft of the transfer case. I tried to remove my cover from this output shaft but there was a snap ring under a rubber plug that needed to be removed but I did not have the tools to remove it. I am assuming that this snap ring was the one that the previous post was talking about being broke. Does not seem that mine is broke. I replaced the front brake pads about 2 months ago, could this be the problem? Any suggestions would be greatly appreciated.
Thanks

 

Wow I would have said a u joint, double check them, I had one go bad and it felt like that but at higher speed. I have had pads drag on Toyota trucks when things got rusty, one side of caliper would release but the other side would drag slightly, would vibrate squeel and even get hot.

 

Its probably not your front axle because you would feel that in the steering wheel. It probably is something with your T-case simply because it stops when you change the drive. Drop your rear driveshaft off the output sp-lines n take a check.

 

Just for fun, check your front drive shaft, likely got bad U joints/slip joint, it does rotate even when not in 4wd, usually it causes vibration at higher speeds

 

T.T. How many miles on your truck and when did the vibration start? My 04.5 was as smooth as a babies behind until about 65K, but now feels exactly as you say...driving on grooved pavement. The vibes increase with road speed and load. The difference is that I feel it most in the steering wheel and throttle pedal. I never thought to dial in 4WD. Good idea and I will try it tomorrow.
To All:Do you figure doing that indicates the problem to be up front or the maind driveshaft? Thanks to anyone that can help.

 

HB, My truck has 70000 miles and the vibration just started. The vibration is only from 5 to 20 mph, then it is gone. After trying to find the vibration some more, I noticed that the vibration seemed to go away when I put it in 4WD but it is actually still there. I am still puzzled as to where this is coming from. Any comments would be greatly apprecited.

 

I had what I think was a similar problem and it turned out to be the driveshaft angle to the diff. Mine is lifted, so it explained it, but it did not start until years after I put the lift in. Found out that the Pinion bearing was wore out. replaced it and vibration went away.

 

You indicated you checked U-joints. However, U-joints can get too tight and cause the problem you describe.