: Info on converter lock,,code PO39



first sts
11-04-03, 08:40 PM
Where can I find information on how the locking torque converter works, what are the parts, and where are they located in the STS, 1995

elwesso
11-04-03, 09:05 PM
Ive found www.howstuffworks.com to be the easiest way to learn about that kind of stuff.... They use pictures and its very easy to understand......

Ill give you a quick overview on how it works.....

What it does is when you reach a certain speed (usually around 40mph, but depends on the stall speed), the converter "locks up" (sorry I cant be more specific, as Im not sure what actually happens to the TC when it locks), and its locked into 4rd gear..... Plus the TC (aka overdrive) is locked, so the input speed is lower than the output speed, therefore increasing gas mileage because of lower engine RPMs..... Then, if you want to, you can unlock it by downshifting into 3rd, and then shift back into D to lock things back up.....

I always recommend when driving in the city to leave the tranny in 3rd, because it will constantly lock and unlock, and thats unnessecary wear on the tranny.... I then shift into D when I know im gonna be over 40 (my lockup speed) for an extended period of time.....

Parts are gonna be (and I probably left some out) basically just the torque converter.... Everything else is gonna be inside the TC itself or in the tranny.....

elwesso
11-04-03, 09:06 PM
Now...... What your P039 means is lockup is not occuring..... I guess you sorta figured that one out.....

Sometimes its the shift solenoids that causes this (I think), or it could be actual wear on the tranny..... Can you get it to lockup at all???

first sts
11-04-03, 09:12 PM
Yes it WILL lock for a while,,maybe 5-8 miles then the warning light comes on,,converter unlocks,,,if I shut off the engine and restart everything is fine for 5-8 miles the it goes off again,,,,,,,

elwesso
11-04-03, 09:25 PM
Well, looking through my Q45 service manual, there's a lockup valve that could be clogged or messed up..... It also mentiones a filter......

I guess Id recommend getting a tranny flush and a filter change and see where that leads you...... Its not gonna hurt anything........

first sts
11-04-03, 09:28 PM
Thanks,,,I know of a good trans.shop that can do the work,,,thanks again,,,,,,,