P0740 code

FireFace · Post by **FireFace** » 14 Dec 2010, 11:37

Hey ya'll I have a 97 850 that is throwing a p0740 code. I have looked at every auto store and no one can tell me what that code is, besides something to do with the transmission. Im in texas so i have to have that light off to pass state inspection. will doing a simple trans service shut it off? any ideas please let me know.

Post by **jblackburn** » 14 Dec 2010, 11:53

That's a code for the torque converter solenoid.

If you don't notice your transmission "locking up" over speeds of 55 where the RPM will drop, it's safe to assume that the solenoid is dead and needs to be replaced.

I'll see if I can find you a thread where they replaced solenoids; they're not in easy to get to places.

Post by **jblackburn** » 14 Dec 2010, 12:01

http://volvospeed.com/vs_forum/index.ph ... try1866207

http://volvospeed.com/vs_forum/index.ph ... r-the-pan/

FireFace · Post by **FireFace** » 14 Dec 2010, 13:15

actually the only thing i notice when drivin is it slips out of reverse. i have a small trans leak and when i put fluid in it it gives me no issues, the light shuts off then comes back on. all i do is put half a qt of fluid in it.

Post by **jblackburn** » 14 Dec 2010, 16:19

There's your problem - if the fluid gets low, pressures aren't able to be maintained, and the solenoids have trouble doing their job. Where is it leaking from?

FireFace · Post by **FireFace** » 15 Dec 2010, 10:55

i really havent had a good chance to look for where the leak is comming from

Post by **jblackburn** » 15 Dec 2010, 23:23

Axle seals and cooler hoses are the most common places. Sometimes the gasket around the solenoid cover will begin to leak, but it doesn't happen all that often.

This is one of the things you will want to track down sooner rather than later; incorrect fluid levels can quickly damage the insides of a transmission.