intermittent torque converter lock up problem.

[ryan8488]

Hi there, I have an interesting problem with the 4 speed auto on a 6 Cyl VL. Basically at random times the torque converter does not appear to lock or randomly unlocks even though my speed is constant (I.E. 100 km/h) It still shifts through all 4 gears but it just does not lock the converter. I should also point out that when the converter does not lock, the PWR button has no effect, as in it will not shift out of 4th regardless of the button position, also even if the accelerator is floored it won't kick down. 50% of the time the transmission works fine and all of the functions (PWR, kick down) work fine. At a guess I'd say it is an electrical / sensor problem and is in some sort of limp mode. Was just wondering if anyone else has had this problem and knows how to cure it.

[ryan8488]

Also does anyone know what speed it should lock up? Mine locks up at about 70Km/h. Perhaps this is normal but to me this seems quite a low speed to lock up.

[detox_nath83]

if driving normal with smooth throttle behavior mine will go into overdrive @ about 80kms when warm of course.

as for your problem could b sensor problem, Possibly Trans Ecu failing as this controls Lock up(Overdrive) or the overdrive solenoid (On the Box itself passenger side).. hows your oil level as well,.

i get this problem of not dropping back to 3rd when i depress the PWR button only on rainy days sometimes. so moisture is the problem from me i guess.

but if i give more throttle it kicks down fine (Light press goes to 3rd)..... (Flat to floor = Top of second) WOOOOOMMMMPPPPAAAAAAAAAAAAA..... :P

[ryan8488]

Thanks for your reply, yeah the oil level is fine and I flushed it too as the old stuff was looking a bit sad. But didn't seem to affect the problem. Anyway I do have a spare trans ECU which I might swap just to see what happens and check the wiring on the solenoids. When mine is working normal it is the same as yours if I floor it it goes into 2nd and she takes off haha.