My 1998 Voyager now has 242 000 km (~150 000 miles) on the odometer. The automatic transmission works great and shifts smoothly. According to the maintenance log, the automatic transmission has never had any maintenance done to it.
After reading a lot of posts here in the T&C / Voyager forum, I've noticed that someone always seems to have a problem with the automatic transmission and people have said that it's a very typical issue with the T&C / Voyager.
The automatic transmission maintenance (fluid change) here in Finland (at the Chrysler dealer) would only cost about 180€. Would it be wiser to leave the transmission as it is and never do any maintenance until there's a problem or is it OK to do it?

 

180 euros seems like an awful lot of money to change fluid in a transmission. I usually pay about $80 at a local Valvoline Instant Oil Change. If the dealer pulls the pan and changes the filter, then it's probably not too unreasonable. The VIOC boys just disconnect the cooler lines and suck out the old fluid and replace it.
It's much better to change the fluid BEFORE problems arise, as bad fluid can cause slippage to occur resulting in VERY expensive repairs. At 150,000 miles yours is long overdue.

 

I had the maintenance done. They changed the fluid, filter and some kind of a seal. Now the transmission works as well as it did before, but now there is this distinct whirring noise whenever you change from P (or Neutral) to D or R. The same sound is also heard at very slow speeds during breaking... Is that normal? Or did they mess up something?

 

normal in all Chrysler tranny that is electronic

 

The color of the fluid might tell stories, and the Mopar ATF-4 in mine has a nice light purple color. A dark color usually is an indicator for trouble. I recently paid 50 euro for four liter original Mopar ATF-4 (you need 3.8 liter to fill it) at a 15% repair shop discount, and draining/removing/cleaning/applying the liquid seal/replacing the pan usually takes 20-30 minutes for a Chrysler mechanic and thus 180 Euro sounds fairly reasonable to me.

Oh and there are actually two filters, one inside the automatic transmission, and one near the AC cooler at the right side of the radiator – not replacing it might cause a quicker automatic transmission repair.