07' XC70 Vibration under load, uphill or accelerating

TerrDawg · Post by **TerrDawg** » 04 Sep 2023, 16:36

of course I'm hundreds of miles from home when I notice a vibration under a load, I felt it in the seat, as opposed to the steering wheel, so that tells me it's coming from the rear-end, right?!? so I check the tires and find the date codes are week 25 of 2016 and week 45 of 2016 and the one on the right is more bald (older one)... so I replace the rears with 225-60-16 some off brand (Saturday on a 3 day weekend) It got noticeably worse ... after reading an article on here, I'm thinking CV joints, but it escalated rather quickly and not making any sounds, it's not subtle by any stretch, so my question is: HOW DO I CHECK MY CV JOINTS hundreds of miles from home??
or DO YOU HAVE ANY OTHER SUGGESTIONS ??
you're wondering why I put cheapo' odd size tires tires on just the rear, it was lowered with BC coils and 215/65/16 Michelins when I bought it and I'm over that, It looks great lowered it's very clean and low mileage so I want to lift it, maybe 2 inches over stock and aggressive new meats so it won't be for long, yes, I know they should all four be the same, I'm working with what I have here
Thanks in Advance
Terry

jking4020 · Post by **jking4020** » 04 Sep 2023, 18:55

I always drive 01 or 02 XC70 wagons. I've had problems with different tires wear patterns in pinches. The vibration is most certainly your tires. Especially if you've been messing with the suspension travel. If it got worse when you switched those tires then it's obviously your tires. CV joints usually do not vibrate your car but rather just make clicking noises. I would get rid of any crazy suspension mod you have and just drive on the proper Volvo specs for the car. If you have four decent tires you should be able to make it home without too much damage. Of course make sure your tranny fluid is good before you go home. Good luck and get back to all the same tires as soon as possible.

jking4020 · Post by **jking4020** » 04 Sep 2023, 18:58

If this helps your conscience I drove with non-matching tires from Lincoln Nebraska to Grand junction Colorado and back to Lincoln Nebraska again. All four tires were to the radials bald at some point but I made it. Some vibrations on the way home. Just remember these Volvos in times of need can be tanks and get you where you need to go. Just keep an eye on your tires.

Post by **Krons** » 04 Sep 2023, 21:33

My kids 02 S60 2.5T had vibration under load at above 60mph and was CV shafts. If you can crawl under you can twist the shafts to see if you can feel any play in them.

Tire vibration should be same/similar coasting as under load.

On tire mismatch keep in mind if the circumference is off significantly on an AWD front to rear the AWD clutch could engage more often than it should burning things up.

Post by **vtl** » 05 Sep 2023, 05:21

Axles outer CV joints. Can't feel any play, can only inspect it visually after taking apart and cleaning them good.

If you are planning to lift, go straight to XC90 2.5T axles. They have no tripods and will last as long as the CV boots are kept intact.

Post by **Blacklab467** » 05 Sep 2023, 07:43

Search "vibration under acceleration". It sounds like textbook CV joint failure, probably the passenger side outer. As Krons mentioned, tires would vibrate regardless of acceleration, braking, or coasting at a given speed.

Post by **vtl** » 05 Sep 2023, 07:50

Blacklab467 wrote: ↑05 Sep 2023, 07:43 Search "vibration under acceleration". It sounds like textbook CV joint failure, probably the passenger side outer. As Krons mentioned, tires would vibrate regardless of acceleration, braking, or coasting at a given speed.

Now it gets tricky here. I was getting acceleration vibration even with both new axles: one Volvo, one GKN (new, not reman). Swapping tires with winter set would only change the conditions when the vibration happened. Turned out LCA front bushings were bad enough to not keeping a proper toe-in angle on high speed.

Another "under the seat" vibration was bizarre, I could not figure out what exactly makes is happening. Gone after propeller shaft replacement. The old one had a sagged rubber around carriage bearing, it was falling into resonance sporadically.

I'd say, I only got rid of all vibrations once I replaced every bit of drivetrain and suspension, which took me quite a years.

TerrDawg · Post by **TerrDawg** » 06 Sep 2023, 12:31

I appreciate and thank each of your responses, It does seem to go away when coasting or letting off acceleration, I don't hear the "clack, clack, clack" that I had heard back in the past, usually while turning and accelerating but this is my first front wheel drive/All Wheel drive vehicle, I usually have a 960 / S90 / V90 or three to drive around at any rate this issue developed and has escalated rather fast, is that normal? lastly, is the XC90 axle shafts longer?, I definitely want to go back to stock height plus a bit more - I'd keep it like this if I were 20 years younger but I'm done with the low thing
Thanks again,Terry

Post by **Krons** » 06 Sep 2023, 18:23

The S60 I referenced had no clack while turning.