2000 V70R: Noise, vibration, harshness

Post by **JRL** » 10 Jun 2015, 14:56

Our 2000 V70R, 129K miles now has developed a nasty vibration and fairly loud noise.
Both start at about 50-55 MPH, is at its worst at 60-70 then gets better over 70. (It's not the tires but that what it sounds like, old, bad snow tires or large truck tires).
It's sort of a deep rumbling noise and the vibration is from the back (the steering wheel doesn't shake at all).

I have to say a caveat here, I know nothing about Viscous Couplings as I've never had a problem with one. I know in theory how they work and that's it!

Balanced the tires today, all are down to about 5-6/32" but they look good with even wear and no cupping.
They were not very far out at all, maybe 1/4 oz. off with the worst so I don't think this vibration is the rear tires.

What am I left with? I suppose the V/C or a rear wheel bearing, what else could it be?
Removed the propshaft earlier today, I had lift access and will road test tomorrow. However since that was removed I can't do a full diagnostic now but I had to do it today.
(I usually remove it every April and install it in Nov. so I am very late this year, but doing this every year has saved the tranny, (still original and excellent at 129K miles)!

Could it be that the V/C just went bad out of nowhere and if so what are my choices here?
I'm certainly not buying a new one, I found one with 65K miles for $350, not bad I suppose.

I will entertain all positive comments and suggestions but please don't say "remove the propshaft" and go FWD, that's not one of them!
We need AWD here in the winter just to get up and out of our 200 foot long, 30 degree driveway and up and down our very hilly street for over 1/2 mile.

Post by **Ozark Lee** » 10 Jun 2015, 20:28

Jimmy57 has a torque wrench test for the viscous coupler that he posted yesterday in another thread.

For viscous coupling AWD in 97-2000 models you jack up one rear wheel with trans in Park and then apply a torque wrench on a wheel bolt on the raised wheel and apply force. The wheel should move smoothly at more than 60 lb-ft and not more than 90 lb-ft. If it doesn't move then the VC has dried up and is binding.

...Lee

Post by **jimmy57** » 10 Jun 2015, 21:10

What you describe can be the VC binding but it also can be the bearing at front of VC carrier housing.
IS the vibration a high frequency vibration that is faster than tire vibration normally? The driveshaft speed is 3.31 times wheel speed so driveshaft related pieces will create vibrations that are faster. They are also usually lower amplitude.

Post by **JRL** » 10 Jun 2015, 21:18

AWD works as new with no noises, binding, clunks, bangs, thunks, etc, so not binding. Bearing in front, possible
Vibration is more like a growl and gets louder with speed up to 70 or so
Starts at 45-60

Post by **850 LPT** » 11 Jun 2015, 07:45

Did this noise appear gradually?

I would still suspect the tires to be the culprit here. How old are they? I had a similar thing happen with my XC when I first got it.
The tires had good thread left, were perfectly balanced and round, but the were so old and hard that the road noise became unbearable. A new set of tires cured the problem.

Other than that, how are the parking brake shoes? Could they be separating and shifting in the drums causing noise?
It's unlikely that the differential could be failing. Rear drive shaft CV joints maybe?

Just throwing stuff out there, good luck.

Dirk

Post by **JRL** » 11 Jun 2015, 17:57

I picked it up this morning and just drove it home, wife took it today, I had to go to NJ
I'll drive it tomorrow at speed but it seemed a heck of a lot quieter and smoother at 45-50 for the mile or so that I drove it home

Post by **JRL** » 14 Jun 2015, 08:13

R drives like it used to, like a church mouse, took it up to 85-90 or so on concrete.
Smooth and quiet at speeds so it must be either the VC or a propshaft bearing. Definitely not a wheel bearing.
This Propshaft has about 55K miles on it, the center bearing looks fine as do the end bearings, nice, tight and spin easily.
Not sure what to do as we will need AWD back next winter.

Post by **scot850** » 14 Jun 2015, 23:09

Hi Jim,

I know you have way more experience than I will ever have, but here is my 2c input.

As jimmy has suggested check the 'nose' bearing at the front of the VC housing. I got a rumble from my 98 XC when the bearing was going. When I pulled the unit out I took it to the dealer as I didn't have the tools at that time to remove the flange or the bearing. When the flange was removed, the bearing fell apart completely, and the dealer had a devil of a job with a long punch to drive out the remaining outer bearing casing.

One other question. Was the car standing unused for any length of time (read weeks)? If so it could be flat spotted tires, sticking rear brake caliper, dragging parking brake shoes or cables. The last one is the VC unit itself. The fluid inside it can settle with sitting and the unit doesn't like it. Running the car for a while can settle the unit without any further work.

Good luck!

Neil.

Post by **JRL** » 15 Jun 2015, 06:33

Big Will also PM'ed me about the bearing
No to #2 in its entirety