So at last I got my S90 to the dealer to have the transmission codes checked. When the guy called me, he first wanted to pull the head and check the valves on #6, saying that the compression was low and that low compression and the resultant loss of power would cause the transmission to act up. I expressed my skepticism about that theory and my unwillingness to spend $2500 (miniumum) to pull the head right now, and eventually he did tell me that the actual transmission code was 332, indicating a problem with the lockup solenoid. His first estimate to replace the solenoid was $610, which seemed only borderline outrageous, so I told him to order the part.

He just called back to say that is now a non-replaceable part, that they would have to order the whole valve body from Volvo, and that it would cost $1475 total. I asked him how big a problem it would be to drive it as it is, with the lockup solenoid slipping some though not all of the time, and he said that it would hurt fuel economy and might eventually strain the transmission, but the impression that I got was that I could probably drive it a long time this way.

Any advice? Is it really the case that a minor loss of power in #6 would affect the transmission? The car idles a little rough but runs very smooth at speed, and I've been getting ca. 25 mpg on trips.

Thanks--

Jeff