When driving in heavy stop and go traffic, especially in a hilly area my transmission will hunt for the right gear. Like down shifting and then up shifting, until either the load is removed or a constant speed is attained. I have flushed the transmission and put in dyno fluid the first time and a dyno/synth blend fluid this last time. The blended fluid improved shifting under normal conditions but still the problem occurs.

When it does occur, if I park the car for say 30 minutes... everything is back to normal. To throw another observation into the mix, it seems most likely to occur when the outside temperatures are from 85 to 95 degrees Fahrenheit, BUT not above or below that range.

I am beginning to feel this is electrical in nature, not mechanical. has anyone else seen this issue with the S90/V90?

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~William~ 1985 240 DL - 365,000 & 1998 V90 - 190,000