Torque Converter Lock Up

[GOBO]

Hi Guys,
I have an NP 05 DID Auto that the auto drops out of lock up very easyly. That is on an open highway in 5th gear (100 - 110 KMS/hr) vehicle not loaded up the torque converter drops out of lock up at the first sign of a hill.
If I am towing a trailer at this speed then even on a flat road it will not lock up. Mitz say there is nothing wrong with the transmission.

My only previous experience with transmissions with torque converter lock up was with Ford 4 speeds with a 5 Litre V8's and they just stayed locked up.

This issue has been well documented in the forum in he past.
I was wondering if any owners of an NT with the 'new' auto transmission were experiencing similar problems as I have had.

[psproule]

What size are your Coopers?

[apsilon]

This is my first auto so to be honest, I don't know how to tell when it's "locked up". If someone wants to let me know I'll give you some feedback as I've done a fair few highway km now.

[GOBO]

My Cooper ATR's are 265/70R16
My Cooper STT's are 245/75R16

By my calcs they are the same diam or rolling circumference as tyres specified by Mits on the tyre placard as standard equipment.

You can see the torque converter lock up by watching the tacho, usually a reduction of about 200RPM when it locks up in 5th. The tacho should then sit rock solid for the constant speed when on cruise control, if it falls out of lock up you will see the revs increase although you are still in 5th gear.

[apsilon]

I'll take a look. I'm due to go up to Newcastle any day now for work.

[apsilon]

OK, finally did some freeway km.

Lockup I find you really have to hold a constant throttle for it to engage. It won't disengage up hill unless you accelerate and my guess is that's what you're seeing. You're either accelerating to compensate for the rise or the cruise control is and that's disengaging lockup.

My opinion remains that auto boxes aren't very smart despite all the electronics that go in to them now.

[ted.t]

torque lockup

Hi Guys,
I have an NP 05 DID Auto that the auto drops out of lock up very easyly. That is on an open highway in 5th gear (100 - 110 KMS/hr) vehicle not loaded up the torque converter drops out of lock up at the first sign of a hill.
If I am towing a trailer at this speed then even on a flat road it will not lock up. Mitz say there is nothing wrong with the transmission.

My only previous experience with transmissions with torque converter lock up was with Ford 4 speeds with a 5 Litre V8's and they just stayed locked up.

This issue has been well documented in the forum in he past.
I was wondering if any owners of an NT with the 'new' auto transmission were experiencing similar problems as I have had.

my my05 exceed DiD is exactly the same ted.t

[GOBO]

Thanks for the replies guys.

I drive from Melb to the Mallee and back several times a year and the vehicle is not loaded up 50% of the time. I expext the torque converter to fall out of lockup on the Calder when Sth of Bendigo where there are quite a few hills to climb.
What I find it is dropping out of lockup when the highway is basically flat and you are just heading up a gentle undulation. If you are heading into a breeze it also drops out.
Is this just an issue for the DID's or do the petrol ones do it also.

[micha3l1985]

My 03 np did, never really dropped out even when towing and cruising into slight head winds till I put a roof rack on it