Volvo 480 Club Europe

Greetings,
I'm having an issue which is starting to worry me more and more.
It all started when I sent the car to the mechanic to replace leaking crankshaft oilseals. I took the opportunity to also ask to replace the other seals that were on it's way out, transmission oil wishbones's bushings etc. So... everything from the gearbox to the wheels was removed and refitted.

After I brought the car from the mechanic, (although not imediatly) I started to have issues on "lift of". I mean from N (0 km/h) to 1st gear (i'm using manual transmission BTW).
The issue was that I felt something hitting from the steering wheel and a sound like "tack-tack-tack" and also a big shake.
The issue seemed worse when I got out from the garage at my work. This because I have to climb a very steep ramp (from -2 to ground level) and because due to access i have to be almost standing still at the ramp before climbing it. Sometimes It was so bad and the car shook so much that once the gear shift came out.
My first reaction was that the drive shaft or the cv joint or something like that was badly refitted by the mechanic.
Because this was happening more and more frequently, I decided to take the car to the mechanic. The next day the mechanic told me that he took the car for a test drive and he could not find anything wrong with it. The only thing he pointed out was that the front suspension springs were both broken (strange... I did not recall them being broken before). Anyway I had a look at one of them and indeed it was broken, although it as on the tip therefore there was not much change to the height of the spring.

Last week I found an even more strange behavior: when I entered the highway, I put pedal to the metal (in 3rd I believe). Once the turbo kicked in the car started vibrating very hard (like the "tack-tack-tack" described above but at much higher frequency) and the clutch slipped leaving the engine free revving. I never had this happening, I mean I already had worn clutches but they only slip, they did not made the car vibrate. Another thing, the clutch is not that old.

Does anyone have any Idea what might be the cause? Do you think it might be related to the spring? I personally do not think so, at least the clutch would not slip. I would like to have an Idea before going back to the mechanic and Avoid the "I did not find anything wrong must be something wrong the car already had"
Thanks for the help and sorry for the long post.

Sounds like the clutch may be contaminated with oil from the rear crank seal.

Either that, or it's just worn out.

I also think it's oil on the clutch. Had similar (but smaller) issues on my 1977 244. I sprayed Bräkleen on the clutch and that took the problems away for a while, but it came back due to leaking crank seals.

Thanks for both your answers.
If its contaminated as you say, will it autoclean itself as I drive? I'm assuming that the seal is not leaking as this was one of the reasons why i took it to the mechanic.If it has to be clean, does the hole gearbox has to come out again? Or is there any way to clean it with the least parts moved?
BTW. Looking at the original post there's one thing wrong. I meant that everything from engine (including) to the wheels was removed and refited (my mind was focused on the gearbox sorry ). Which reminds me can it also be due to engine/gearbox mounts?
Thanks again.

silly maybe but is the 'anti sway' shock absorber been re-fitted on front of engine, tucked down between the timing cover and front chassis leg?

when they are 'poor' the engine will thrash about and then that will cause a noise?

also check the REAR engine mount UNDER the car near the exhaust/gear lever etc

Hi I did not have any time nor availbility to be without car since my last post. So I've been delaying my trip to the garage.
However, the problem has dissapeared in the mean time.
So, maybe it was the disc that was contaminated as you guys said.
Any way I'll keep an eye on how it behaves for the next few months.
Thank you for your help.