Thread: "Help" TD5 towing van

Thanks to all for your replies and detailed at that, much appreciated and puts it into perspective. I will keep the auto lockup in mind. I guess it will be a bit of trial and hopefully no error.I've towed vans for over 20 years but most vehicles are different as to procedures and how to do it.
Many thanks Steve

Having done 30 trips with the car trailer on over the last 2years with cars, boats and tractors on the trailer, (no not all at the same time), I found that with the auto in D and on cruise control, the cruise will drop off going up hills when the go pedal has been flat out for a while. I soon worked out that it was easier to go back to 3 as the speed fell back to 95, then the cruise control stays on and you can hear the engine note change as the speed gets back to where it is set at. Leave it the till you get over the top, then put it back to D. A damn sight easier than driving a manual.

Thanks BBD I will do that with third gear Cheers mate

Hi all

This is a very interesting thread. I tow with a D1 Tdi Auto. Can my gearbox also lock up in 3rd?

Adrian

It's the same ZF box I believe, just hydraulically controlled instead of electrically controlled.

Easiest way to check, is put the stick in 3 and drive. Keep accelerating gently in 3rd and above 70km/hr it should lockup ... will be easy to tell if it's locked as when you put your foot down, the engine won't flare anymore as the TC slips.

Originally Posted by Fluids

Steve.

You actually have 6 gear ratios to work with.

1-2-3-3Locked-4-4Locked.

Sport mode just moves the autos shift points upwards - you'll hold each gear to a higher engine rpm before the auto upshifts. The engine produces beter HP at higher revs, so you'll get up to speed a little quicker. Sport mode would be beneficial if you're doing a lot of stop/start towing.

Using Sport or Normal, here's how I approach it. My experiance has been towing 2-2.25t car float/car.

Leave the stick in 3rd. Accelerate away. Once the auto shifts to 3rd, keep accelerating, and at around 70km/hr, the auto will lockup the autos torque converter in 3rd gear. Now you have a solid driveline, with no auto "slip", with a 1:1 gearing. Right foot effort now is applied to moving the vehicle, not spinning/slipping the auto and heating up the transmission. Once you are above 80-85km/hr you can upshift to 4th. The torque converter will unlock 3rd, upshift to 4th, flare a little (slipping), then as long as you're far enough above 80km/hr (bigger the load/right pedal, the higher above 80km/hr you'll need to be to get the torque converter to lockup in 4th) the torque converter will lockup, and you now have a solid driveline again, without auto slip, and a gear ratio of 1:0.74 (overdrive!).

The challenge now is to KEEP the torque converter locked up. You'r approaching a hill out on the highway. Anticipation is the key. Before you hit the hill, pull the stick back to 3rd. The torque converter will unlock 4th, and drop to 3rd unlocked, it'll sound like it's reving hard, but a short few seconds in 3rd unlocked, and the torque converter will again lockup in 3rd. Now keep your foot into it, and it will pull like a freight train up the hill ... too much loud pedal, and the torque converter will unlock 3rd and rev its tits off. Once you crest the hill, make sure you're over 80-85km/hr, and shift back to 4th, at which point the torque converter will again lockup 4th.

To keep excessive temperature out of the auto transmission, try and keep it locked up wherever possible. Your engine is happier revving harder in a lower gear, than labouring in a higher gear ... and it will be producing MORE horsepower EASIER in the lower gear, reving harder, and with your torque converter locked, MORE of your horsepower gets to the back wheels, instead of heating your transmission.

The torque converter doesn't seem to lockup in 3rd if the stick is in D (unless your in Sport mode driving like you stole it - that's my experience).

3rd locks up around 70-72km/hr, and doesn't unlock until around 50-55km/hr, so with some anticipation, you can get into 3rd lockup and then cruise around at 60km/hr with a solid driveline, again, without overworking the auto transmission. You have to downshift to 3rd ABOVE 70km/hr, and give it a chance to lockup in 3rd, then you can decelerate down to your lower urban speeds.

Sport mode doesn't seem to affect the lockup points. Lockup appears to be more influenced by the size of the load your pulling vs how much loud pedal you are using (or aren't). If you want it to lockup, and it appears it won't, ease your foot off the loud pedal a little.

Hope that was as clear as mud!

Absolutely correct, I couldn't agree more. This is excellent advice.

Easiest way to check, is put the stick in 3 and drive. Keep accelerating gently in 3rd and above 70km/hr it should lockup ..

4HP22 as in Disco1 and RRC only locks at 85Kmh in 4th only.
Regards Philip A

Thanks for the heads-up Philip !

I just assumed ...