Towing in overdrive

Generally, we don't risk it. It is worth using the extra fuel rather than risk loosing the gears in the outback. We pull a heavy van with a Patrol 3 ltr td, and my husband (who generally doesn't let me drive with the van) keeps the revs around 2500 - 2750. One day he forgot to put the overdrive off after a day of driving without the van, and he wondered what was wrong - it was jumping up and down between the gears sending the gauges crazy. Much smoother with the overdrive off. With our manual landcruiser similarly we don't use 5th gear when towing a heavy load. I hope you enjoyed your trip.

I'll get my head bitten off again, but here goes.

Firstly for saying that if you phone Toyota or Nissan they will tell you not to tow in top gear in either a five speed manual or a 4 speed auto. In the auto they say it gets hot, burns the Trans fluid which stuffs the whole thing up.

Secondly for saying that lately I have come to the point of saying.....STUFF IT!!!
I now tow our Jayco outback Finch in overdrive and can now comfortably sit on 110 or 120 and even 130 depending on the road conditions/weather etc;

As soon as the speed gets back to 100 I drop it back into 3rd and sit back on about 98klm untill I can get up and going again.

The Jayco is only 980 kg so this will not be as heavy as your caravan, and my next "add on" for the car is a larger trans cooler.

I do tow in 5th in the manual diesel pajero, and usually use 5th at just above max torque of 2000rpm, at about 2300/2500rpm, or 85/95 km/hr. 100 is 2700.
However, I do change down earlier to 4th than I would without something behind, and heavier the load, earlier I change to keep 4th (or the next gear) at the best rev range for power, and the same again if I go down to 3rd, or even 2nd with the trailer sailor.
I try not to lug the engine, and do not use full throttle in 5th, but use 4th instead.

I tow at different times:-
1. 750 kg camping trailer - tows really nicely at 100km/hr in 5th.
2. 1200kg caravan - tows nicely at 90/95km/hr in 5th.
3. 2200kg trailer sailor - max speed about 85km/hr, ocassionally in 5th when level or down hill. Might do 90 at the bottom of a hill in 5th, as I like to be slow over the crest and gently accelerate downn a hill. \/ to the poor people behind, but I do try and keep left and are very aware of traffic behind me.

I always understood from my mechanical text books that bearings are killed by load AND lack of revs.
I change gear box oil on a regular basis too, every 2 years or 50,000k.
Done 263,000k now since new without any transmission porblems.

FWIW I agree , tow in overdrive /5th as long as you don't labour the thing . The way I see it the situation is like tyre pressures , it all depends on what you are doing where , there is no hard and fast rule . When I tow I am acutely aware of the load and when I come to a rise knock it back to 4th , same with strong headwind . If your load is so heavy that you are labouring at 100Ks think about buying a bigger vehicle for safety reasons as well.
Cheers dave L.

The most common component that get overlooked by most vehicles fitted with automatic transmissions is a decent oil cooler for it. The standard factory oil coolers really aren’t up to the task under heavy, extreme or prolonged loads.

Fitting a good after market cooler will enable you to tow with confidence in overdrive – but the general rule of thumb is to be sensible in your driving techniques and don’t take risks in remote areas.

120-130km p/h with a van in tow.... is that safe? Is that legal?

I refer you to POST number 33,830 and re-print my comments from it.......

"Not sure about Toyotas, but with my GU Patrol 4.2TD, the BIG difference between TOWING in 4th and 5TH is the EGT. The manifold temperature when travelling at around 100k/h DROPS by around 100 degrees C if I drop the old girl back to 4th GEAR after working her at around 2050 revs in 5TH. Revs go up to around 2500, but temp DROPS from around 530oC to around 440oC (these temps are very "ball-park" as the actual temp varies considerably depending on head winds, gradient etc).
Just to expand on the matter of gradient.......even a slight uphill section of road will see the EGT rise by 60 to 100 degrees.
My camper trailer weighs around 1200kg and I do drive in 5TH GEAR as long as the EGT gauge tells me that it is sustainable. I also tend to be guided in my GEAR selection and speed, by keeping an eye on my Boost gauge.
IMHO anybody with a turbo vehicle, especially an aftermarket fitted one or one that has been tweeked, MUST fit the EGT gauge as a minimum and preferrably a boost gauge as well.
My Patrol was a 2000 model that suffered from the 5TH GEAR spline problem and Nissan replaced it at around 80,000klm under warranty, BEFORE it actually collapsed.
My advice is that it is (or should be) okay to tow in 5TH GEAR in the right circumstances. By that I mean that you should drop back to 4th GEAR as soon as you strike a slight hill or if you are aware there is a head-wind etc. Basically, you should never make the vehicle labour in 5TH GEAR.
Just my opinion and may not be relevant to your Tojo.
Cheers mate
Roachie"

YMMV

Hi Shanebo,

I also have a landcruiser auto towing a camper trailer (750 kg). So I rang a few gearbox specialists and they all said if its in overdrive and is hunting in and out of 4th-5th gear take it out of overdrive.
So now I drive in overdrive on the flats and turn it off when I come to hilly areas have kept a eye on the trans oil it has been fine it gets changed every 40 000k. If you are going to do a large trip then maybe as said before a larger oil cooler would help.
regards
Col

Hi All,
This is a very timely post because I’ve just got back to work after what should have been three weeks sitting on the beach at Warroora Station. I say should have been because , you guessed it, gearbox bearings called it quits half way to Geraldton. In the past I had always towed in fifth believing it was only autos that you needed to be a little gentle with but not so, apparently. $1200.00 and 5 days delay we finally got to our destination a little wiser for the experience. Incidentally, O’Briens in Geraldton did the work on Terrano and I was very happy with their service so if anyone else needs work done on their 4bs they were good with us.

Hi Guy's

Thanks for all the info, I believe the best thing for me is to use overdrive only on the flat,at 90kph as my van weighs 1600kg.As our next trip will be to Hervey Bay your info will be helpful

thanks
shanebo