AW55 hard downshifts.

[vtl]

Check axle bolts, they either have to have rubber cones or be replaced every time, since they are torque-to-yield bolts. Bolt with rubber cones can be reused.

Also check CV of propeller shaft, it's a common wear item. Angle gear collar sleeve also a wear item. When it strips a couple of time, the angle great has to be replaced.

Slacken off the upper mount bolt, start the engine tighten the bolt.

AW55 does not like kickdowns in general. Even a healthy transmission will not live long.

[dikidera]

The current axle bolts I have, have washers and no rubber bushing. I contacted a genuine volvo parts supplier and he said even the new bolts have just washers, but I guess they have to be replaced.

My S60 is only FWD so no angle gear. I guess I should mention that the upper and lower torque mount were easy to replace, no engine jacking was needed. It seems like when the engine is off, they are simply at idle state which seems weird.

As for the upper mount, should I be in Park or in gear?

[vtl]

The upper mount has to be at rest with the engine running, otherwise there will be vibrations.

[dikidera]

The upper mount has to be at rest with the engine running, otherwise there will be vibrations.

Could I possibly test if it's the reason I have vibrations at idle by fully removing the bolt? I also want to mention something I think might be important, if I slightly raise the RPMs in Park, the vibrations disappear(or are not very noticeable).

If it makes any difference, the upper torque mount is Corteco, while the lower torque mount is genuine from Volvo. The lower right engine mount is also Corteco.

[vtl]

Find a tuner who can raise idle revs from 650 to 800 RPMs. Mine idles at 800, much less vibrations.

[dikidera]

So..I went back and did what you said with the upper torque mount. I noticed no difference. Actually there was. When I removed the bolt, there was more vibration, so turns out that mount is absorbing some vibrations, so the culprit is either the two subframe hydraulic mounts OR the right passenger mount having more firmer rubber.

Worst case...subframe bushings and those are a PITA to change, so much so that I saw no clear videos on youtube of someone replacing them.

I also noticed that the kick when going from Drive to Park is still there. It does feel like the tranny is dropping in place or being kicked.

[Blacklab467]

The subframe bushings are easy to change. I posted a thread last year on how to do it if you do a search or I could copy the link for you. They are also relatively inexpensive for the Volvo ones.
I chased a similar slamming into gear by changing all the motor mounts also a couple years ago with no success. The symptom of slamming into Drive or reverse from park or neutral is more likely a valve body issue, if memory serves correct it is a sticking SLU solenoid. I bought a TransGo shift kit which included everything needed to rebuild your linear solenoids (there are three) and my transmission was like new after that, also cleaning up a shift flare that was driving me crazy.
BTW, the hydraulic mounts are the front and rear engine mounts, and they're not difficult to change. The subframe bushings are a common rubber torsilestic bushing that fits into a bore with a minor interference fit.

[dikidera]

It's the reverse for me, I think. The car slams OUT of gear(by going from Drive to Park). This is either solenoids...or torque converter? In fact could my idle vibration in gear be caused by a faulty torque converter? Or the engine mounts I have is simply of harder rubber. The right side engine mount is the closest to the crankshaft and makes sense to transfer more vibrations.

As for the bushings I'll have a look around for your thread - the easier I can do that - the better.