Thread: torque convertor not unlocking 4 speed

unlocking or locking.
They usually lock at 85Kmh in a 3.9 Range Rover. I think 3.5 Rovers locked at 70Kmh. And ditto while slowing down.
Are you sure its not locking? It feels like a gear ratio change.
Regards Philip A

im pritty sure its locking my brother has a 3.5 and u definately feel it lock and unlock , but mine is lockin i think because wen u go up a hill in 4th it labours just like my brothers but with his it gets that extra rpm when the torque converter unlocks, before it changes into 3rd.

It is only speed dependent. So it only happens at the set speed. The accelerator position or load makes no difference.
Have a look in your manual for the lock up speed. As I said in a Range Rover 3.9 it is 85Kmh. But I think in a 3.5 it is 70kmh, so that is why you may not notice it in yours but do in your brothers.
The car would start off with the converter locked as the slip as you take off is from the converter.
Regards Philip A

Did it used to unlock? You've replaced the 3.5 with a 3.9 haven't you?

PS - Nice County [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

Bruce.

I do not think that there ever was a County 3.9 auto. My guess is that the auto has been added from a Rangie or Disco.

look, an auto will not idle in Drive , Reverse or any gear unless the torque converter is slipping!!!! The torque converter must slip to take off from standstill.
So you could not drive the car unless the torque converter is slipping.
Regards Philip A

To wizard thanks im getting there. bought the county with the auto so im not sure what the box is out of ,then put the 3.9 in. i know the auto slips and i know that the auto locks up in 4th but its not unlockin at 70 or 85

pay with the kick down cables on the throttle/butterfly part of
the manifold. mine now kicks down from drive to 3rd at 85kph.
it never used to kick down at all! till i played with the cable.

phil.

ps. PhillipA, i thought that a convertor locked up at a certian
rev range?? like a stall convertor??
i was told that a 3.5 and zf locks up above 1500rpm??

is this so??

Stall and lock are two different things.
The 3.9 converter stalls at 1500RPM. ie the slip reaches a minimum. or the stator and rotor are travelling at the same speed +-10%.
"stall" converters for some reason are only called that in OZ. Everywhere else AFAIK they are called "high stall converters". This is where the stator and rotor are a different design so that the speeds only equalise at say 2000RPM.
The pupose is to give more torque multiplication off the line, as the slip is a "lower gear" and to allow engines with poor low down torque because of a big cam, to jump off the line better, and in some cases to allow a modified engine to idle in drive

The lock is a clutch which is engaged to physically connect the stator and rotor in the torque converter to eliminate slip and give better fuel economy. In a hydraulically controlled auto like a 4HP22 it is activated by the governor( I think) , while in electronically controlled transmissions it is controlled by the ECU and can be varied , and even locked in low ratio etc to give better braking.
I am not too expert on Autos so if anyone thinks this is wrong or can give a better explanation , please do.
Regards Philip A