[Kristopher]

So I have this odd vibration in the front of my '95 Classic. I thought it might be the front drive shaft, so I had it balanced. Vibration is still there. So I am hypothesizing that maybe, just maybe, it might be my rattling cats. Here is what is happening:

No vibration at all under 60 mph. At 60 plus I get a vibration that is, oddly enough, controllable by throttle input. Under a normal cruise(no load) no vibration, but add about 10-30% throttle(like climbing a hill with cruise contol on) and the vibration appears. In addition, there seems to be a soft vibration on decel too at the indicated speeds.

I am thinking that the cats might be bad enough that the vibration could resonate at a certain engine rpm. What I have not done is try a different gear, i.e change the rpm relative to speed.

Does anyone have any insight?

--Kris

 

[John C]

I don't think it's the cats.

You don't mention if you have a lift? Did you check the u-joints on the rear driveshaft? Did you check the TC bearings, pinion bearings?

I would remove the rear DS and drive around and see if the vibe goes away. If it doesn't then remove the front one.

Good luck.

 

[Kristopher]

Ok, so I am going to have the rear DS balanced too. It is the only item that I do not know anything about. I got it used, seemingly in good condition.

--Kris

 

[John C]

Kris, before you get the DS balanced go under your Rangie and grab the DS (front or rear). Try moving/rotating the DS, if there is some movement/play than that's the bad DS. You might have to replace the u-joint or the bearing on the TC side or the pinion side.

Again, you don't mention if you have a lift or not. If you have a lift than that might be the cause of the vibration. By lifting the vehicle you changed the geometry of the driveline.

Let us know if you have a lift.

 

[Kristopher]

I do have a 2" Rovertym lift. I spoke with Seth at RT today and we went through a check list of things, everything from motor and tranny mounts to suspension links and DS's. It is relatively inexpensive to have the DS checked and then balanced as needed. Even with new joints it would be less then $100.

--Kris

 

[Jonesy]

Kris - I own a 95LWB like you. And like you I have this "vibration" I think you are referring to. In mine it isn't really a vibration that shakes the wheel or anything, it is more of a noise and it happens between 71 and 83MPH...then teeters off to 95MPH (fastest I dare to go with VA troopers )

When I bought it the bloke said his mechy told him it was the DS that needed balancing - so I couldn't find anyone that would balance a DS???? Where did you get yours done????

I now have a vibration in the front but as the tires are worn it is pointing to the fact that I need a full wheel balancing and front end alignment - maybe bushings but they look OK - dunno about U joints....i just had the 75K mile service and nothing was reported wrong. I know my front needs work because above 70MPH the hood shakes and vibes ont he front right. Do you have any other tell tale signs???:rellye

 

[Kristopher]

Well all seems well now. The rear shaft was a little tweaked. Thanks for the input!

--Kris