Towing advice

[jaco_n]

I bought a 2nd hand Conqueror Commander which weighs over 1 ton when loaded. I have a 2005 3,2 DID LWB and currently leave the gears in auto when towing. Is this the right thing to do or must I force it to stay in 4th gear?

[Roelf_le_Roux]

Firstly, an autobox doesn't have a "direct drive" like a manual. It's a jungle of sun, moon, planet (and maybe even more heavenly bodies) gears.<br />I absolutely support the manual option, once at speed. The manual aption is referred to as "sport mode" because the ECU does a quicker change and the engine torque is just slightly reduced. Normal auto shifting happens with a bigger drop in torque and takes longer, which means less stress on drive train components as you accelerate up to speed.<br />The thing to keep an eye on is the torque converter clutch. You don't want it open the whole time (it generates heat) and you don't want it engaging and disengaging the whole time.

[Roelf_le_Roux]

There is a lock-up clutch in the torque converter. The default setting is open. When the engine load is reduced under cruising conditions, the clutch will engage.<br /><br />If you are cruising at 100km/h (towing a van on a level road), that clutch will be engaged. Press down a bit with your foot on a mild hill and the revs will suddenly jump 200 to 300rpm higher - that is the clutch disengaging and drive is through the torque converter. As soon as the road levels off the revs will drop again by the same margin - torque converter clutch engaged and drive is now via the clutch. Under these conditions the clutch is engaging and releasing the whole time, which obviously leads to wear, which adds to heat and clutch material contamination in the oil and thus filter. <br /><br />I'm not saying the box is going to expire after your first holiday trip, I know it won't. I'm saying that the fairly common auto box niggles at the 250k to 300k mark is due to this type of driving, combined with less than ideal maintenance. My preferred driving mode is to keep an eye on the rev counter and the road conditions. You soon learn where the "tipping point" is for the clutch to disengage. If your load, speed and road conditions are such that the clutch is in and out the whole time, then rather slip the box into 4th and allow it to cruise with that little torque converter lock-up clutch constantly engaged.

[Bosuil]

Great advice, thank you Roelf. I have found the auto box on mine to hunt at the slightest uphill which is not only frustrating but will eventually take its toll wrt longevity on the transmission. It also has a slight "drinking problem" when towing in auto. LOL

[jaco_n]

Awesome, thanks for the info!

[Bosuil]

Quick update.

Towed approx 400km this weekend, mostly in 4th gear as recommended by Roelf. Man o man, what a difference it makes. Suddenly feels like the car is in it's element, towing like a dream. Also much better fuel consumption. (5,2km/l vs 4.5km/l)

Thanks for the great advice Roelf. Can now see why you loved your V6.

[Roelf_le_Roux]

And still missing it