Does the torque lockup totally bypass the gearbox?

I can distinctly count 4 gears before the torque lockup kicks in. Although what I sense as 3rd and 4th seem to be very close in ratio.

It will distinctly change into 3rd at around 30mph and then the engine drops revs slightly (around 250) at around 40mph. Then the torque lockup engages at 52.

Everywhere says the gearbox is 4 speed, but surely in practice it is actually 5?
 
Does the torque lockup totally bypass the gearbox?

I can distinctly count 4 gears before the torque lockup kicks in. Although what I sense as 3rd and 4th seem to be very close in ratio.

It will distinctly change into 3rd at around 30mph and then the engine drops revs slightly (around 250) at around 40mph. Then the torque lockup engages at 52.

Everywhere says the gearbox is 4 speed, but surely in practice it is actually 5?


No, it's actually a 4 speed auto, with torque lock-up, it just feels like a 5th gear.

Imagine the torque converter (TC) is a bit like a clutch, in that it permits a certain amount of slip, like you can do with a clutch. However, once the TC lockup function operates, there's no more slip, so the revs drop.

Cheers
Dave
 
I think this gearbox actually has lock up on all gears, if you drive with the box in third you will find it also locks out in that gear. Also, the lockout only activates after the box is warmed up, so it won't happen immediately, this is determined by engine temperature, air temperature and a timer. In the summer the lockout comes in earlier, in the winter later. The gearbox has no temperature sensor. The lockout actually works fully when the box is in low ratio, this is so the box acts like a manual, if you use the gears, with no slip for descent and climbing. The one big difference is the computer will disengage the gear if it senses an engine stall. Hope this helps
 

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