1998 V70 T5M Vibration - How to tell which CV Axle is bad?

[Seaway]

Are you sure it isnt an engine vibration under load? A misfire when you step on the gas will feel like wheel problems - if the vibration is load dependent I would look at engine rather than drivetrain

I don't think that is the case, but I will check into it. I don't have any codes, or any pending codes. I don't get any misfires in neutral when revving the engine - though it is obviously not under load at that point.

It certainly feels like the drivetrain as I can feel it both in the steering wheel and the seat of my pants.

The car also has new plugs (NGK gapped to .025) and a new fuel filter. I was having spark blowout before I changed the plugs and gapped them down. I am running an ARD Green Tune (at 17 psi). When I was having the spark problem the engine felt like it was shuddering or hesitating at high rpms, but there was no vibration as there is now.

[abscate]

One of the posters above reports vibration under acceleration cured by inner CV tripod, so i think my post above qualifies as 'junk on the internet worth ignoring'

[Seaway]

One of the posters above reports vibration under acceleration cured by inner CV tripod, so i think my post above qualifies as 'junk on the internet worth ignoring'

Ha! I appreciate any and all input as I have yet to figure out the problem. Getting the car aligned (again) helped a lot, but the vibration is still present. Power is not down, I have no misfire codes, and no other symptoms that make me think it is the engine. If I were to accelerate slowly (like a normal person) I would not get the vibration. I have visually inspected the hydraulic mounts and they are not leaking. All the other mounts are new. The axles do not have any play in them according to my mechanic, and I also tried to manipulate them and didn't feel anything - though I have no idea what I was trying to feel other than movement. I do have a bit of steering wheel wobble that happens right at 70mph, even after having the tires balanced.

I am changing the oil this evening and that will give me another excuse to get under the car with a flashlight and see what I can see.

[abscate]

Hmmm. Have we ruled out tranmission as cause? The fact that normal acceleration 'cures it' is pushing me that way.

[Seaway]

Hmmm. Have we ruled out tranmission as cause? The fact that normal acceleration 'cures it' is pushing me that way.

Nope, I haven't ruled anything out. It is a manual transmission if that means anything. How would I check for problems with it?

[abscate]

Another idea down the drain. You are killing my perfect record this week...

I guess I should have noticed the T5M in the title.

Clutch slip under load - chattering?? This is really far fetched though. You could test my seeing if the clutch slips under load - parking brake firmly on, slip clutch in first until the engine either stalls or duplicates your vibration. No more than 5 seconds for test.

[Seaway]

Another idea down the drain. You are killing my perfect record this week...

I guess I should have noticed the T5M in the title.

Clutch slip under load - chattering?? This is really far fetched though. You could test my seeing if the clutch slips under load - parking brake firmly on, slip clutch in first until the engine either stalls or duplicates your vibration. No more than 5 seconds for test.

I don't get any clutch slip and certainly no chattering. The clutch has about 15,000 miles on it. It is an 850R clutch, so it handles the modest power I am pushing with no problem. And putting the parking brake on "firmly" would require a fully functioning parking brake which I don't really have. I have thrown all the time and money at that particular issue as I am going to. But that's a whole new thread...

I am doing all this front end work in order to get everything tightened up for a 19T install in the near future. I have all the parts for that, I just want everything else in working order before I do it. Here is a list of repairs I have done to the car in the last 10 months:

Previous owner 5,000 miles before I got the car:
New 850R clutch
Volvo RMS
Throwout bearing
Trans with 150K on it
New timing belt w/water pump

O2 Sensors - Bosch - (186k) 1/18/2015
Torque Mount (IPD) 1/26/2015
Transmission Mount (OEM) @ 186k
Silicone vacuum lines from TCV
Snabb intake pipe (w/new PTC valve)
Used AC blower motor
Heater core (Alvo) (189K)
Mishimoto Intercooler Hoses (188k)
Silicone coolant/radiator hoses (188k)
Rebuilt rear Brake calipers, new Bosch Rotors, Akebono pads, new E-brake pads (189K)
Rebuilt Left Front Brake Caliper (189K)
Rebuilt Turbo (new CHRA) (188k)
Jewel headlights and corner markers (New @ 188k)
Interior LED lights (188k)
ARD Green Tune (17psi)
Oil changed (189k) (Rotella T6 5w-40)
Battery @ 187k - NAPA
Air Filter @ 188k
New Passenger CV Axle (NAPA - $50) @ 191K
IPD Strut Brace
Front Brake Pads (Akebono) @ 191K
Boost Gauge @ 191K (Glow Shift)
New thermostat (Calstat 87) @192k
New ECT sensor @ 192k
New Spark Plugs @ 192k (NGK BKR7E gapped @ .025)
New Bosch ignition rotor @ 192k
Installed CJ Yother Down pipe and cat @193k (9/23/15)
New cabin air filter (10/7/2015)
New front rotors @ 193k (Meyle Platinum)
New Upper Engine Torque Mount @ firewall @ 193k (Hutchinson - OEM)
New Front Engine Mount @ 193k (Rein Brand)
IPD rear sway bar installed @ 193k (track spec 25mm)
Meyle HD control arms installed @ 193.5k
Bosch fuel filter installed @ 193.5k
New Meyle tie rod ends @193.5k
New transverse arm bolts @193.5k
Four wheel alignment @193.5k (10/16/15)
Wheels balanced 10/17/2015

Next on the list is an new rear shocks as the current ones are leaking.

[Seaway]

Double checked the axles and wheel bearings. There is no play in axles and there is no movement in the wheels. Leaning towards motor mounts or possibly a bad tire.

Upside is I changed the oil.

[Seaway]

Are you sure it isnt an engine vibration under load? A misfire when you step on the gas will feel like wheel problems - if the vibration is load dependent I would look at engine rather than drivetrain

You may have been right after all. I had a little misfire today in traffic on my way to work home from work. Nothing bad enough to throw a code, but it was evident. I swapped in an old set of plug wires I had and took a short, spirited drive. Lots of wheel spin, no shaking and the power feels better than it has been in a long time. The old Bougicord wires were date stamped 6/14, but one or more must have been bad. I will know for sure if it is fixed on my ride to work tomorrow.

Thanks for everyone's patience and help!

[Seaway]

Well, I think Abscate nailed it. Car is running smooth with no vibrations under boost. It is a good feeling to finally get it corrected, but I am kind of embarrassed for having missed something that is, in hindsight, so obvious. I should have checked the wires more carefully, date stamp or not.

I have some new wires being delivered today and I will get them installed before I hit the road for a family visit tomorrow.