Towing a caravan

Here is the reply I posted there

Okay here goes

I tow a 2800kg van with a TD 100ser croozer.

At 90 kph on a flat road the engine is doing 1800 rpm in 5th gear and is below optimum torque range and the Exhaust temp goes up to 400 deg+ as the engine is lugging and working harder to maintain speed.

Before anyone says Well just kick it down.

Well on a light throttle it will just stay in 5th and lug

In 4th gear it is at 2400rpm which is right in the sweet spot and the exhaust temp hardly gets above 325-350deg.


Thats enough convincing for me I always tow in 4th

It also makes no appreciable difference to fuel consumption.

Leaving it the same gear also reduces wear on components in the auto as well.

I would also be reluctant to tow any van at over 100kph as tyres can

give you a sudden sharp shock especially on a single axle setup.

Thats my take on things you can take it or leave but it works for me and has for 50,000k

Snoopy one, your are right on the money!

Hi Grant

I totally agree with snoopyone. Its not worth using 5th gear when towing.

Can i say that again? It is not worth the risk towing in 5th gear (or overdrive in an auto). They are not towing gears.

Motherhen

Yes switch off the O/Drive or tow in 4th gear.

Thankyou for your view on this topic. Your reply sounds logical and I think I will stick with 4th gear for towing

I will stick to 4th gear as it seams to be the same view of everyone else. Thankyou for your input.

They're Jaycos so they arent that heavy.

Some never learn no matter what you tell them.

Go up to 100k and watch the fuel gauge go back rapidly

A guy near where I lived had a big Coromal. Tows it with a Patrol.

The front wheels are nearly off the ground but he doesnt need a WDH so he reckons.

You know what they say Snoopy, "When you argue with a fool then there are two fools.
Or
No matter what intelligent advice you give to an idiot they will always beat you into submission with their stupidity.

Cheers, Bruce.

OK, thats the argument for 5th in a manual box.

What about an auto and specifically a Prado that has a torque converter that locks in at 82 kmh and runs at 1800 rpm and then will go to 2000 rpm at 90 kmh.
Once the rpm gets to about 1700 or a steep hill it kicks down and runs at 2300 rpm.
Do Prado people tow in 3rd gear on that basis?

Isn't that what an auto box is for, to select the appropriate gear with the option of an over-ride for really steep hills or a headwind?

Bill

Bill,

Toyota's 200 series has a 6 speed auto. They recommend towing in S5 (manual mode, 5th gear). I wouldn't be surprised if there's a similar recommendation in the Prado handbook.

Hi Bill. My 120 Prado auto tows a 2.5 tonne Jayco in 4th. I never notice the lock up dropping out on hills. It just seems to drop straight back into 3rd and on the bigger hills even 2nd. If I anticipate the hill is long or steep I will actually pull it back to 3rd around the bottom of the hill. It is a petrol so not sure about the diesel. Cheers,Bob

Yes

Hi Snoopyone,

I agree that a manual is better in the 1:1 gear (4th generally, but may be 5th in a 6th speed), but I am not too sure if that matters in an a late model auto? Generally the auto gearboxes have their own ECU and adjust the gear according to the load.

Also I agree that EGT's are higher in an overdrive gear, but thats to be expected. You roughly put in the same amount of fuel for the load but when you go down a gear you put in more air. As a diesel EGT is simplistically fuel/air ratio, the EGT is always going to be lower in a lower gear for the same speed/load.

As long as the EGT is not excessive, does it matter if its ~50C higher? I haven't seen a 100C difference, 50C is about the max difference I have seen, but I am sure different vehicle EGT's behave in different ways.

Cheers

Captain

Well Im sure it does as on a slightly undulating road my auto would hop in and out of O/D all the time so I now leave it in 4th and it sits there happy as all day.

Why wear out the box simply because you can

Yes they do adjust to the load as all autos do Thats why they hop up and down as the load increases and decreases.

Put it in a lower gear and it doesnt do that as the gear can take the undulations.

MY EGT sits between 300- 325 in 4th at 90kph Drop it into 5th and its straight up over 400 every time.

Hottest Ive had it was 512deg on a long hill on a hot day.

Had to drop it into 3rd and slow down before it got tooooo hot.

Also got up around that going from Batemans Bay to Canberra on a cold wet day.
So its 4th for me everyone else can please themselves.

Cheers

Best weigh it may give you a surprise and be illegal.

Probably wont affect you towing if thats all it weighs.

Probably can in a Prado with 180 litre tank

I would get far if I tried that as I only get 5.7kpl at 90kh in a TD Croozer

I went to see the country not see how far I could get in a day LOL