torque converter lock-up

[Jeremy L-Jones]

Hello all

Small thing seems to have happened since I last drove my truck... its a 93 import with auto box, o-drive switch and normally locks the torque converter above a vertain speed.

The lock-up seems to have stopped working, the box behaves like a good old fashioned slush-box at speed. I'm assuming its more likely to be an electrical issue and suspect the solenoid controller has gone but if anyone has any suggestions or experienced the same I'd be grateful for some advice. The truck hasn't done much work this summer as I've been very busy so could also be something sticking but now I'm probably just imagining things...

Thanks

Jeremy

 

[Jon Wildsmith]

There are a few things that can prevent lock up, like the water temperature sender failing and the ECU won't lock till a certain temperature has been reached, a blocked cooler pipe or cooler can prevent enough pressure in the lock up mechanism for it to engage, the solenoid can fail and the lock up friction material can fail. You'd be best tapping into the SL wire at the ECU and attach a meter so you can see if the problem is the ECU not trying to lock or the lock up not working and go from there.

 

[Jeremy L-Jones]

Thanks for this Jon...

I'll have to take it to someone who can... don't have the diagnostics kit

Cheers

Jeremy

 

[Jeremy L-Jones]

Just driven back from Canterbury to London. The box was locking up ok at low speeds, between 40 and 50 but anything above it wouldn't.

Then suddenly it locked at about 70 mph and continued to do so into central London.

Just wondered if it could be in some way linked (no pun intended) to the throttle kickdown and therefore mechanical...

I'll get it plugged into a diagnostics asap but unlikely to be able to do it until November...

I'll see what happens...

Jeremy
]

 

[Jon Wildsmith]

You could check if the cable from the injection pump to the gearbox is moving freely and returning, they can get stiff and jam up. I know that cable controls how much pressure is put on the clutch plates for gear changes but it might also inhibit lock up even if the ECU is telling the box to lock, worth checking just in case?

 

[Jeremy L-Jones]

will do... thanks Jon... is access best from above or below...?

Jeremy

 

[Jon Wildsmith]

above, just look at the side of the injection pump and check the cable that goes off towards the back of the engine bay and the transmission tunnel has retracted. If you work the throttle cable by hand or get someone to sit in the truck cycling the throttle you'll be able to see if the cable is moving in and out freely.

 

[Jeremy L-Jones]

Cheers... I'll do it in daylight...