The OEM stock driveshaft will probably cost you a lot more than $270, I'd go with the AL one TTT mentioned.

word yo.... MT TII - $421, MT aftermkt - $267, MT AL - $382.5

Or you can prob find a used shaft for $50....


Is this an auto/5spd? n/a TII? I've got a few n/a S4 shafts in the basement...

NA S5 non lsd 5-speed manual

It seems in looking for used parts, I have the hardest driveshaft to find.

Are the yokes between S4/5 the same?

They are listed completely different parts.

Now, on my way home, i discovered something. While the car has even the slightest part throttle through WOT the vibration is there, also in neutral its there, and when the car is moving but motor is shut off, however, under engine braking/deceleration the vibrations and rumble disappear. Now i am quite confused.

Pull the d/s off and take it to a d/s shop and have them spin it up looking for vibrations, they'll check ujoints too. If the d/s comes back clean, it's the diff. you telling me that there's no vibe on decel tells me possibly diff.

Thanks, now to locate one that will not rip me off, and hold out till I get my dad's truck fixed. His hand surgery will turn that job in to a me work and him supervise job.

Well guys, Max chiming in on my own problem:

I had the car up on the lift at work (Volvo Dealer) and the little stub shafts that come out of the diff had a lot of play in them. At first I thought it was the axles, but now I'm questioning that it's the diff?

One REALLY strange thing is: as I accel to 4th gear on the highway, I get NO vibration in 4th... Then I up-shift into 5th and bam, brrrrrrrrrrrrrrrr, there it is.

Does anyone have a clue as to why the vibration would disappear in 4th at 65mph?

Well, saturday morning i may try to drain the diff and see what comes out, but I have to replace the fluids immediately, since its my dd. I have 3 quarts of GL5 75W90. Is this the proper fluid? All the FSM states is API Service SAE90.

Could my diff issues be related to driving it hard when it was -10*F here? and not using the SAE80W diff fluid?

So at 65 in forth there's no vibs, but at 65 in 5th there is vibes? Could be harmonics, could be tranny

Yup, proper fluid for an n/a S4 diff. No additives needed.

Was it warmed up? If so than nope.

Is it possible my problem is more related to completely shot trans and motor mounts causing improper tail shaft angle?

Noise & vibes in every gear except 4th sounds like shot tranny bearings to me. When the trans in my '85 GSL-SE was on its way out, that's basically what it was doing. Fix was a tranny rebuild. 4th is a 1-to-1 ratio, which explains why the noise/vibes change dramatically. In my FB, it sounded like marbles rattling around in a coffee can in all gears except 4th, with a noticable change in driveline vibration that you could feel if you pay attention to it. Symptom was more noise than vibration though, however the FB didn't have an independent rear suspension like the FC does, so the noise/vibe characteristics would likely be different.

Well, I'm about to pick up a spare diff and a spare transmission. I'll let you know which one fixes it.

I'm gonna try the differential first because it's easier to do, if not, then the transmission is next in line.

After all that nonsense is fixed, I'm finally gonna be able to tune my damn car at a dyno, hell yes!

Tranny is WAY easier than a diff.

And for the tranny bearings to cause that much slop, well, those bearings are destined for my wall of shame, hall of failures, I dun blowed it up shelf