Good day fellows. I am experiencing severe rear vibrations when reaching 50 MPH to 70 MPH. Vibrations stops when gas pedal is released. It is pretty bad that is sound like a helicopter on my back. I check and replaced gear at the differential, there's little metallic residue and the oil still looks good. I re-balanced the rear tires but all these efforts remains futile.

Was there anything at the back that could vibrate this much at this speed ?

Will this be a bearing or shaft issue ?
It is very sad, I can't enjoy my nice ride on this kitty.

Hope that somebody can assist me to move forward.

 

I say bearings. Jack the rear up, grab the tire at 12 and 6, try and wiggle the tire up and down and see if there is play. Even the slightest play, time for bearings.

 

I'm sure this isn't it, but while you're at it, you should check the rubber jurid coupling between the prop shaft and the diff. They get hard over time and can cause vibrations.
Scott

 

Thanks much Scott for your prompt guidance on this issue. By the way, how do you want me to check this so called coupling ? Are there any precise procedure to follow other that visual inspection ? Any specific guidelines to have a new coupling installed (can I just remove the old and slap in the new one) ?
It looks like I may have to remove the exhaust pipes ????

 

Visual inspection on the Jurid coupling. You're looking for excessive cracks or signs of delamination. It's a unbolt/bolt-on affair (or it is on my Jag, at least) but pay close attention to hich direction it faces. There's usually a forward face and a rearward face.

I also would suspect the axle shaft u-joints. If they're absolutely on their last legs and about to come apart you'll be able to see and feel obvious free play. However, before they get *that* bad might just be on the verge of seizing....which can set up a heck of a virbration. The only way to check for that is to remove the shafts and actually feel the movement of the joints which, of course, should be totally smooth.

Cheers
DD

 

Can you clarify this a bit?






Where?



Cheers
DD

 

Doug, thanks much for your very productive response. The metallic residue was found at the differential drain plug, ..not that much basing on the age of this kitty. I will move forward in replacing both joints and coupling as per your advice. , just by looking at it, .these was never been touch or replaced, it is as old as this kitty.

There was quite a little play when I check the transmission mounts, I am not sure how much play is allowed on this one...I will also check if these mounts will require replacing...will hit four birds in one stone. Maybe, the propeller shaft vibration affects the integrity of these mounts.

Again, thanks much Doug.

 

Hi any result on this one?