Thank you every one for sharing your experiences - I will be taking the car to an independent Volvo shop in the near future and they will do a scan as well as clear any codes, and possibly they just might go away on their own when I finally drive the car on the road. This has been interesting ...

I am wondering about stored codes from the previous transmission - as soon as I had installed the second trans., connected the battery and turned the ignition to the run position all of the dash lights came on but the arrow was flashing, this before starting and driving the car.

I would think one ...

Good call on the Haynes manual - plan on getting one myself. Also, if you end up with a pre '99 AW 50-42 be sure to transfer the two speed sensors on top of the transmission as they are specific to the Denso system/canbus electrical - which makes the '99 a overall better vehicle than previous models ...

I checked the FCP Euro site and the speed sensor that goes to the multipin connector housing that also has the pnp switch connector is different, 1998and earlier part# is 3515266 whereas 1999 is 9496115.I guess that answers my question and thank you for confirming! The other sensor at the back side ...

What year was the 850? As the transmission I have is from a 1998 S70 there could be a compatibility issue just the same since it is a Denso system in the '99, I was going to swap them but did not find any information beforehand - 1995 and earlier 850 transmissions had one sensor in a different ...

Do a search on this site - there is a tutorial for a re and re transmission involving an 850, basically the same. I had to do two in the last few months due to contamination in the first replacement trans. and now just put in the second one. And to think I bought the car for very little because it ...

I have been searching online and trying to find out if , after having the battery disconnected for a month while doing a transmission change ( AW 50-42 ) whether the codes generated by the failed original transmission causing a flashing arrow/ check engine warning on dash might still be retained ...

Thank you for verifying this - I was pretty well certain they would be interchangeable but was not quite sure abut the sensors.

I replaced the coolant damaged original AW 50-42LE ( cracked pipe in radiator end tank ) with another from the same year S70, unfortunately that 50-42 also had issues ( water intrusion from improper storage ) which were not initially apparent until installed so I now have to re and re again, found ...