1998 V70R - troubleshooting ⬆ torque converter lockup failure ⬆️ (a long-term minor problem)

atomicthumbs · Post by **atomicthumbs** » 25 Apr 2020, 15:26

I am tired of the blinking arrow.

The issue is thus: when starting from a blank slate, all codes reset, if I cruise at ~56 miles per hour or more and the road begins to be even slightly uphill, there's a 75% chance the torque converter slips and unlocks, throwing (if I remember right) a P0740 code from the AW50-42 computer. The arrow begins blinking, and the car refuses to attempt to lock up the TC until the codes are reset. My gas mileage suffers; not so great for a car I'd like to take on road trips. The mostly constant blinking arrow masks any other transmission failures that might pop up someday, too.

This began after I had to drive a family member to the hospital, quite some distance, and the throttle position sensor failed 5 miles out. Turning around wasn't an option so I drove there using the "W" button to switch between the limp-home 1st/2nd gear and W 3rd/4th gear modes. The torque converter didn't like that and the blinking arrow started on the way home. It sacrificed itself to save someone else.

What's the most likely thing to be damaged here, and is it possible to replace without dropping the subframe, or without pulling the engine, or without a new transmission?

Elliot2007 · Post by **Elliot2007** » 26 Apr 2020, 05:19

My 1998 xc70 awd would not move at all especially on uphills I swapped out the atf fluid with new merc3 dextron and has been amazing sense then. Not sure if this is your issue just thought I would share if it could help you. There are amazing links for doing flush on this site that I used

Sommerfeldt · Post by **Sommerfeldt** » 26 Apr 2020, 05:24

Hey!

For a P0740, I'd say it's most likely a solenoid problem - those are at least the thingies that go most frequently. Luckily, they can be replaced from outside the transmission. You should get the car's codes scanned by something that reads Volvo specific codes, but you could also try to replace the "S-L" solenoid, which is the torque converter locking solenoid.

I don't have a V70 (or 850) anymore, so someone might correct me on this, but if it's the SL, then the P# is probably 6843784.

- S

atomicthumbs · Post by **atomicthumbs** » 26 Apr 2020, 14:28

Sommerfeldt wrote: ↑26 Apr 2020, 05:24 Hey!

For a P0740, I'd say it's most likely a solenoid problem - those are at least the thingies that go most frequently. Luckily, they can be replaced from outside the transmission. You should get the car's codes scanned by something that reads Volvo specific codes, but you could also try to replace the "S-L" solenoid, which is the torque converter locking solenoid.

I don't have a V70 (or 850) anymore, so someone might correct me on this, but if it's the SL, then the P# is probably 6843784.

- S

Thank you; I've been using this app, which has proven invaluable. Way more helpful than Torque and it can do things like trigger the AW50-42 solenoid test mode through a regular Bluetooth adapter. https://play.google.com/store/apps/deta ... i&hl=en_US