Thread: 4.4TDV8 take-off TC slip with van

Mine is fine Graeme....but it has had the ECU remap from Roo Systems ("Towing and Touring") and I don't know if that makes a difference?
cheers

Thanks Chris. I expect that a remap would make it not comparable and a remap for towing even more so. Does your's hold 2000 or more rpm until well into 3rd gear, even without the van unless just creeping off the mark? Moving the van in stop-start traffic is most annoying.

The engine and gearbox software is at the latest levels that LR have released to the public but later versions could be available through a dealer. I realise that the diff ratio in these vehicles is very high and my oversize tyres make the ratio worse and the lower ratios in this early version of the gearbox are poorly spaced but there's no need for the TC to slip holding the engine at 2000 rpm or more.

I also put load resistors parallel on the camper trailer. It still doesn't recognise its there.

Do you mean that the reversing sensors aren't disabled? I didn't try rock crawl to see if off-road height was automatically selected.

Nothing changes. It doesn't recognise there's a trailer connected.

Excuse my lack of knowledge,,
but theres no way to shift the 8 speed manually?

seems like the engine is overpowering the gearbox,,
believe it or not mine does a similar thing with the van on,,

Manual up-shift is what I do to stop the TC slip but by doing so I have to keep manually shifting or hold the up-shift tab for several seconds to return to auto mode which apart from possibly up-shifting thereby dropping revs inappropriately low, finding the tab in traffic with the steering wheel turned often results in the down-shift being used. Manual shifting in traffic where turning is involved is not practical.

The TC slip is gearbox programming to prevent revs dropping low. Once a little speed is attained (maybe 30 kph?), lifting off the throttle will lock the TC then gently re-applying throttle will leave the TC locked but this procedure isn't suitable for use in traffic.

These engines have copious torque allowing quite brisk acceleration in 3rd gear away from side-street corners from 1000 rpm if the TC stays locked but sluggish acceleration once the TC unlocks unless given a boot-full. Towing a van exaggerates the TC slip.

Torque converter unlock then slip has drastically reduced since gearbox adaptations were recently cleared. The TC now stays locked at low revs in 3rd (eg 1000 rpm on light or medium throttle) which seems to occur turning most street corners. I haven't had an opportunity to see if TC slip has reduced when accelerating in traffic let alone with the van attached.