This will hopefully not be difficult. The right rear nivomat shock makes a whirr, flurr, purr noise as it is recovering from extending and going into compressing phase. as the shock quickly rises up(extends) and quickly starts to lower(compress) its right at the transition point we here the constant noise. Its like a wind blowing into a tube that make this bird, flurr, whirr noise. no clunks. Cant really tell if they are shot with only 74k miles on them. Bounce test reveals maybe, maybe an excessive bounce but its so minimal its hard to tell. So the big question is, would a valve on the self leveling be bad making this noise. it has been going on while under warranty but it was so sporadic it could not be found and no point in bringing it to the dealer if I cant find it.

 

Hi there,

I've literally just replaced my rear self-levelling shocks (2005 edition though so might be slightly different model parts to yours), and they are unusual beasts actually. Firstly, if you push the car down and you get bounce then I'd say yes they are shot, the reason being is that self-levellers don't do the regular extend/compress and a sudden shock like that won't allow them to fully travel, so if yours are doing that they sound gone to me.
Mine managed 130k miles, and it was only the bushes that were worn but I've since replaced the whole thing. I went for non-self-levelling as the cost of replacing both self-levelling was going to be around £800 (UK). The parts were patented by Mopar so are dealer-only to get hold of.
I did a video of the replacement and in the description I've put all the part numbers from the ones I took off, and the ones I put on for reference if it's of use:

To me, sounds like yours are on their way out though.

 

Hi,

Nice video, much appreciated. I'm actually checking my van to make sure it needs the shocks, as it seems they too are selfleveling... Although mine are for a 2013 town & country, I think they're not that different and the video helps a lot. By the way, any opinion about the change yet? Apart from being new, do you think the change of type of shocks is ok so far?

All the best,

Carlos .