Disco 2 Disco TD5 Auto - TC lockup

Morning all,
Can anyone explain when the TC should lock up? I had noticed it locked up at just over 50mph however recently I have noticed this doesn't happen until the engine has warmed up. Is this normal?

It may have always done it but I've been using it to go to work which is a short journey barely long enough to get the engine hot

its normal

Great. I was hoping it might be, just wanted to check the TC wasn't cooking itself! Is it based on engine temperature or is there a thermostat in the box?

its to get box upto working temp, there is a temp sensor in the box cooler system

That explains it then. I just had a quick look at RAVE and it just says the lock-up is dependant on throttle position, engine speed, operating mode and the range selected on the transfer box.

The temp sensor on the oil cooler is exclusively for high temp warning, the input goes only to the instrument pack it's not part of the management but the engine temperature is sent via CAN from the engine ECU to the autobox ECU and it's part of the overall autobox management strategy so IMO that's the relevant element in this

I sometimes think that the gearbox would overheat rather than drop lockup in 1 mph earlier.

To be honest it is not a great autobox, it is pretty average, and the control is a bit pants.

I have a lot of experience driving 4 speed electronically controlled GM gearboxes and to be honest they were a lot better, better control, better lockup usage, better shift quality, much better at reading what the driver actually wants. 4 speed longitudinal box, predecessor of the L322 box. Only thing the ZF box is better at is handling the torque.

The last auto I had was a Borg Warner 3 speed on a Maestro Vanden Plas in the mid 1980s and the Disco one is infinitely better. The shifts are almost imperceptible and it seems to do everything I want. Maybe I'm easily satisfied......

iansoady said:

The last auto I had was a Borg Warner 3 speed on a Maestro Vanden Plas in the mid 1980s and the Disco one is infinitely better. The shifts are almost imperceptible and it seems to do everything I want. Maybe I'm easily satisfied......

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The older 3 speed boxes with small engines are pretty terrible.

Jatco feel very fragile.

My worst driven is a 3 speed in a Cavalier, then a Ford Granada, then Jatco 5 speed, then ZF non electronic, ZF electronic, GM 4 speed 4L30 range, however the big LR too many gears ones seem fine, but not enough experience to rate them. But around 140,000 miles with the GM box

Newbie question..... How do you know that your TC has locked up?

Spot1 said:

Newbie question..... How do you know that your TC has locked up?

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By the rev counter showing the engine revs have dropped at a round 53 mph, that is at a steady drive and not flat out pedal to metal acceleration beyond.
Lots of info on the www already help yourself.