So I have a 95 4Runner, 4WD V6 and have had an issue of ridiculous vibration while above 30-40 mph and coming off the gas. All my research has lead me to think it's U-Joints on the drive shaft that are the problem.
In all the videos I have watched, there is enough slop/play on the damaged joints they are replacing to rattle the shaft back and forth. When I get under my truck, I am unable to wiggle or rattle the shaft in any direction. Could this mean the U-Joints are not the problem?
If so, what other type of problem can cause hard vibration when lifting off the accellerator. There is a known issue with the EGR sensor that I am working on fixing as well as a few other engine issues, but I wouldn't think they could cause this type of vibration.
Thanks in advance,
Andrew
Seized ujoints will also cause vibrations and you can't feel that without pulling the shaft.
If you would like to view some video on proper U-joint analysis then go to Weber Auto / u-joints on You tube. This guy is very thourgh. In short, U-joints will cause vibration if they are not balanced. Meaning even newly installed u-joints will contribute to vibration because they are not centered well upon installation. As said in previous post, tight U-joints are as bad as loose u-joints. Here is a pic of a u-joint I took apart on a Mid-year Corvette that looked fine from the outside. I took it apart just because I was changing all the others. But also, if yours appear to be taking grease well then I would not suspect them.
Even a slight roughness can cause a vibration. Pull the shaft and check for smoothness.
If you have to change the U-joints mark the shaft and ends to make sure you put it back together with the same alignment.
The short answer is if they are original replace them. I have looked at many u joints in vehicles that I could not see slack but out of the vehicle you could see they needed replacement.
The one in my wagon i replaced last year had an issue with grease not getting to all four. It locked in place and shook like crazy. Zero slop moving it by hand.
