Torque convertor locking and unlocking

[irdonn]

My torque convertor is locking and unlocking when cruising, particularly under cruise control.

Is this a transmission out job?

Transmission is smooth as a BTR can be and serviced regularly.

Ian

[Day-mow]

sounds like you need a manual :P

[irdonn]

Haha...

[The Monty]

Solenoid S6 I believe. Its gone on my old gearbox, kind of annoying with a hi stall converter.

[irdonn]

Thanks Monty. Is it something that needs to be done to prevent further damage, or can it be ignored?

[5.0 ED]

S6 is soft shift.
S7 is lock up.

Take more notice of how it does it, if its unlocking at lighter throttle and locking as a bit more throttle is put in, then first of all try doing a EEC reset. If it dont help, then measure your TPS voltage and move throttle to see if it goes smoothly up and down, if it spikes/jumps then TPS faulty, might look good and TPS could still be causing the issue's.

Personally i doubt it will be anything in the transmission itself, more likely a sensor/setting, since the Engine management commands the transmission when to lock up and unlock, if the lock up wasn't working at all, well i would be thinking trans, otherwise look at sensors and easier things first...

[irdonn]

Thanks 5.0 ED, yeah i thought it might've been information being sent to the EEC causing it to play up, just looking at worse case scenario.

It always happens on the flat, and a lot more noticeable when using cruise control at slight throttle. It's had the EEC reset more times than I can count on my fingers and toes. Sometimes it's fine, but more often than not it cycles up and down. I wonder if the cruise control might be having issues maintaining a constant speed, and it's slight fluctuations are just causing it to unlock and lock?

I might just get a new TPS from Rock Auto. Can someone confirm the correct part number as TH157T or SS10387? They don't appear too expensive.

[BHDOGS]

The solenoids just unscrew from the trans mission anyway easy enough to change ur urself.

[irdonn]

But it needs to be dropped, correct BHDOGS?

[stavros68]

I had a severe locking up problem with mine it would stay locked once it go hot you tried to take of and it was locked in 4th, the solenoid sits at the front i think near the pump or you could disconnect the lock up with disconnecting the light blue wire on the tranny harness , its a tranny out job to fix.

[irdonn]

Thanks mate.

[The Monty]

Hmm, S7, I was close, lol. When it went in mine, it was a constant, lock, unlock, lock, unlock etc, just under cruising conditions.

[irdonn]

That pretty much describes my symptoms.

[irdonn]

Does anyone know what other parameters cause the convertor to lock and unlock? It idles perfectly, smooth as at WOT, it just doesn't like being held at a constant speed.

[5.0 ED]

Lock up is based around speedo drive and tps, gear position sensor, trans temp etc.

It does not go off Engine RPM, engine maf readings or pretty much anything engine.

You could see how it responds in third gear, when the touque converter locks up in third and if it continues to do it, im not sure how that would help diagnosis wise though..

The other thing is get the S7 wire and put a test light on it, and get someone to watch what the test light does while driving it/when the problem arises. if light stays constant, there's a problem in the trans....

[irdonn]

Thanks again 5.0 ED, I tried it in third yesterday but still playing up. It is intermittent though. Sometimes it will do it constantly, and other times once every two minutes or so. It does seem to be a lot worse using cruise control, but it is still noticeable driving it manually too.

I'll pull the good book out and have a look for the S7 wire. Thanks for that idea.

Ian

[kylesampson]

I will soon be towing a van.
In reading a couple of relevant articles and it seems that towing at a speed that the converter is "locked" has a number of advantages. IE keeps the trans cooler, better economy.
Consequently, I need to know HOW TO DETERMINE WHEN THE TERRY IS RUNNING WITH THE CONVERTER LOCKED. It may sound a bit dumb of me but any advice would be appreciated.
With thanks
Kyle

[madmelon]

Some of the Haynes/Gregory/Ellery service manuals have the shift schedule and lock/unlock schedule in them for the older models. Perhaps this is available for the newer models too, though I expect you'd be better off asking in the Territory forum (this is the AU section...). As 5.0ED says, it doesn't necessarily depend on vehicle speed...