850 automatic transmission

milesursogood · Post by **milesursogood** » 11 Nov 2009, 00:05

[quote="MadeInJapan"]No, it's not the same...actually there is a transmission speed sensor which causes the engine to run at different speeds as well as a Vehicle Speed Sensor...I'll post both fixes from VADIS below:

madeinjapan, i'm assuming the vehicle speed sensor has anything to do w/ the faulty gearbox problem in this thread?

Post by **MadeInJapan** » 12 Nov 2009, 15:45

I don't have a clue- the thread is over 2 years old- I'll go back and re-read....

donis222 · Post by **donis222** » 02 Feb 2013, 12:46

My 855 has had a hesitation (slip) that was worse in the cold. After much searching and a flush, PNP cleaning and a valve body cleaning, I found the problem. The seals on the transmission get hard and don't seal well, especially when cold.
I used Lucas transmission fix and after a week the problem is largely solved. This allows fluid to leak aroung the seals and increases the time for the pistons to lock the clutch.
There are a number of products that may work just as well. I am angry with myself

as I knew this from many older cars. The problems that I had experienced with them was not shifting into gear when cold. These were the transmissions that didn't rely on solenoids to shift, but pistons to open and close passages.