Torque converter NOT locking up...

[Jeremy L-Jones]

Hi there

Just wondered if anyone had experience of a torque converter on an 80 series not locking up. Julian V has replaced the lock up solenoid valve which seemed to do the trick but now its not locking up... although it did twice on a drive home tonight. It seems on overrun, foot of the gas, it unlocks then won't lock again.

Just wondered if anyone had similar experience.

Thanks very much

Jeremy

 

[OG.]

Yep.... my 90 started doing that. Just waiting for it to come back after a gearbox rebuild....

 

[Jeremy L-Jones]

Sounds expensive.....


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[Jon Wildsmith]

Does your TPS cable from the side of the pump to the gearbox move smoothly?

When I lost lockup on my old 80 I T'd into the lockup solenoid wire near the ECU and connected a multi-meter so I could check the ECU was telling the box to lock, which it was. In my case it was because the lock up mechanism and friction surface itself in the torque converter was knackered...

 

[Jeremy L-Jones]

Thanks Jon. Its all a bit strange. After start up, once the car gets to about 40mph it locks up fine - for about 20-30 minutes. Then on deceleration or overrun when slowing down, I boot the throttle and it goes through the gears but wont lock up. Almost feels like its temperature or pressure related...

After replacing the TC lock up solenoid all was fine for about 3 weeks, now no longer. I'll check the cable but any diagnostics I'll have to go to Julian Vs again as I'm not kitted out. It doesnt feel like a gearbox rebuild... but never say never...

Jeremy

 

[OG.]

If its the same as a 90 gearbox (and I believe it to be very similar) then lock up can be restricted by the temperature sensor (separate to the guage sensor), hi/lo selector switch (known to suffer from water ingress) and the brake switch (easily tested by pressing the brake pedal and checking the lights come on).

The temperature sensor prevents lock up until the engine is warm

 

[Jeremy L-Jones]

If its the same as a 90 gearbox (and I believe it to be very similar) then lock up can be restricted by the temperature sensor (separate to the guage sensor), hi/lo selector switch (known to suffer from water ingress) and the brake switch (easily tested by pressing the brake pedal and checking the lights come on).

The temperature sensor prevents lock up until the engine is warm

Thanks... there seems to be a temp sensor for the box that monitors the transmission fluid temp.

 

[OG.]

Thats not the one - that just controls the A/T Temp warning light.

The one you need is on the engine monitoring coolant temp.

 

[Jon Wildsmith]

I would want to know if the ECU is powering the lockup solenoid when you're not getting lock up, so you can tell if it's something like a sensor issue so the ECU doesn't try to lock it, or the ECU is trying to lock it but something in the box / TC is not working.

 

[Jeremy L-Jones]

Thanks Jon...

 

[Jeremy L-Jones]

Mysteriously, the box started to lock up as normal, behaved like it should... until tonight... suddenly back to the slush box.

Will attempt to sort in about a week.... feels like its sensor/electrical rather than mechanical....