300Tdi ZF lock-up?

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Originally Posted by nice1guv

Just shift to 3rd (or lower if needed), and it will hold that gear and not go above it.

If you're talking about off-road, then low range and holding 1st makes for a slow descent.

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Low 1st in the auto is still terrible compared to the manual in terms of engine breaking.

The ZF (elec' control) behind the Td5 in low range locks the TC when the overun causes the engine revs to climb to approx' 1800-2000rpm .... does not the ZF (hydraulic control) behind the 300Tdi do the same ?

Same gearboxes.

Quote:

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Originally Posted by Discomark

This is said to be due to the higher (200psi) pressures in the cooler during lockup.
Cheers
Mark

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Not sure about higher pressures in the cooler but the oil temperature definitely falls, as the torque converter is not longer slipping and putting energy into the oil. With the converter locked, it's just like a manual in top gear with the clutch engaged - solid drive all the way from the flywheel to the road wheels.

I too can vouch for the marked lower fluid temperature in lock-up mode.
I put a temp gauge into the cooler line of the Jatco auto in our pervious Toyota Cressida and the temp was a lot lower when towing in 3rd 'locked' than in 4th when it wouldn't reach lock-up due to the towing load.

Damn shame the 300Tdi ZF can't be made to lock in 3rd without spending $mega.

Thanks all for your answers. Ian