What happens when towing in top gear.

[Fab1]

If your running a old 4 speed tow in 3rd,running 5 speed tow in 4th,6speed in 5th etc.

[Croydon]

Thanks Fab certainly something to keep in mind.  I had been told this but now I know why.  Never too old to learn, cheers......

Dave

[big Neil]

Another "pearl of wisdom" from Fabian. Your input to this site is immeasurable. Cheers mate. BN

[Fab1]

1 hour ago, Croydon said:

Thanks Fab certainly something to keep in mind.  I had been told this but now I know why.  Never too old to learn, cheers......

Dave

No problem.The ironic thing is many people tow in top thinking you actually save a heap more fuel when infact if you slow down a little and tow in saw 4th you don't use that much more if any.

1 hour ago, big Neil said:

Another "pearl of wisdom" from Fabian. Your input to this site is immeasurable. Cheers mate. BN

Thanks mate.This post may just save someone that isn't aware of the risks to be towing in top.

[Welster]

Hey Fab wouldn't this only apply to overdrive top gears?   Not so much an older 4 speed with 1:1 as top? 

[Yowie]

Whenever towing, tow in a gear that is a 1:1 ratio. For some of the newer vehicles, that might be 5th or 6th gear of an 8 gear auto box.

You might think you are saving fuel towing in the highest gear (less than a 1:1 ratio) but you are increasing the temperatures of the auto transmission fluid, or manual gearbox fluid, which will decrease the life of the fluid and the gearbox.

With some of the newer vehicles, a high temp in the auto box will cause the vehicle to go into limp mode and you are not really going anyway very fast at all.

[Sigma]

So, how would you keep your gearbox at a lower gear if the box is automatic ?

We just bought a new Pajero Sport 2.4 Turbo Diesel last year and they didn't come in manual. It has a 3.1 tonne towing capacity and we tow around 1.7 tonne.

I suppose we have sports steering shift and you could do it that way but you would constantly need to change gears and on a longer trip, you could forget that it's in sports shift mode.

When I drive it down the M5, it sits in top gear and I can't even feel that we have the boat behind us.

The box is 8speed auto. Should I worry towing it in full auto mode?

 

[Yowie]

Sigma,

I would be wary of towing up hills in auto. The auto box will hunt for the right gear, up and down a few times, and this is what raises the temp of the tranny fluid and causes it to overheat. 1700 kgs is not too much, so it may be O.K. If the Pajero hunts between gears a few times going up a fair sort of hill (eg. Mount Ousley) in full auto, it would be wise to select a lower gear, and lock it in until over the hill.

My van has an ATM of 2900 kg, tow it with a Landcruiser auto, and I use the selector to lock it into 4th gear, at a 1:1 ratio (5th and 6th gears are overdrive - all those gears do is raise the tranny fluid temp)

Smaller boats are not a problem, towing large boats around the weight of a caravan will eventually cause a problem as well.

If you tow heavy weights a lot of time, a large van or heavy boat, it is a good idea to have the tranny fluid changed every so often. Toyota usually states the tranny fluid is set for life, no need to change it, but if you look at the colour after a lot of heavy towing, the fluid can be quite a bit darker and not functioning as efficiently as it should in keeping down the temp. (Auto Transmission experts  state the fluid needs to be changed every few years when towing heavy weights)

About 50,000 kms can be a good time to change the tranny fluid. Ask Mitsubishi to check the fluid colour around that time during a service.

Edited September 3, 2017 by Yowie

[Fab1]

7 hours ago, Welster said:

Hey Fab wouldn't this only apply to overdrive top gears?   Not so much an older 4 speed with 1:1 as top? 

Yes,it applies to the overdrive top gears in a 5sp manual and above.A 4 sp manual 4th is it's  1:1 strongest gear.Older 4sp autos like in the commodores and Falcons for instance you should put the gear shift in 3rd while towing.

Yowie has given some great tips to everyone too.

Remember the harder the car has to work the higher the risk of transmission failure..

This is an example of how I tow using my 5sp manual Hilux and my 6sp auto cerato.

With the Hilux I tow on the freeway using 5th gear when the road is flat and slightly down hill with a tailwind.As soon as there is a slight grade or I'm travelling into the wind I put it in 4th.

If I'm climbing steep grades it's usually 2nd or 3rd gear and when decending steep grades it's 3rd or even 2nd depending on the severity.

With my cerato I keep it out of drive and manually shift gears from start of trip to finish using all 6 gears as above.I only use 6th on perfectly flat,slight downhill with a tailwind.

 

 

[New Signing]

I've already done one gear box in my 2005 Pajero, its not something i wish to do again so this advice is great

[rickmarlin62]

my mate has 07 Nissan patrol and they recommend not towing in fifth  .it struggles to pull my vsea on freeway in fifth but my rodeo goes like like the clappers..go figure..4.0ltr non turbo against 2.8turbo..no contest..rick

[Welster]

2 hours ago, Fab1 said:

keep

 

2 hours ago, Fab1 said:

Yes,it applies to the overdrive top gears in a 5sp manual and above.A 4 sp manual 4th is it's  1:1 strongest gear.Older 4sp autos like in the commodores and Falcons for instance you should put the gear shift in 3rd while towing.

Yowie has given some great tips to everyone too.

Remember the harder the car has to work the higher the risk of transmission failure..

This is an example of how I tow using my 5sp manual Hilux and my 6sp auto cerato.

With the Hilux I tow on the freeway using 5th gear when the road is flat and slightly down hill with a tailwind.As soon as there is a slight grade or I'm travelling into the wind I put it in 4th.

If I'm climbing steep grades it's usually 2nd or 3rd gear and when decending steep grades it's 3rd or even 2nd depending on the severity.

With my cerato I keep it out of drive and manually shift gears from start of trip to finish using all 6 gears as above.I only use 6th on perfectly flat,slight downhill with a tailwind.

 

 

I do something similar in my 5 speed manual jackaroo I use top gear but am very aware whilst towing to not use 5th under load.  The V6 seems to  like a few revs. 

My 68 fairlaine with C4 likes to stay  at home. 

For those with an auto I think a transmission cooler would be a great addition as well. 

Good topic guys.  

 

Edited September 3, 2017 by Welster

[Sigma]

Thanks Yowie...

So, from my understanding, your gearbox oil heats up when it's working harder like when you are towing up hill in higher gear but is ok on flat roads like the M5 etc....

I don't push my car hard as I don't like hammering the car to get where I want to get.....always leave early and take off slowly. Watching some of the others on the road hammering their cars when towing as if they were in a Ferrari in a race.

I just watch them, shake my head and think....."That car ain't going to last long!". I know this is the case cause I have a mate that does this and his car(s) are more at the mechanics than they are on the road.....and he wonders why, lol!!

[Trailcraft43]

Great post Fab.

i never even thought about it before.

wont be towing in 5th anymore that's for sure.

cheers

marty

[Yowie]

8 hours ago, Sigma said:

Thanks Yowie...

So, from my understanding, your gearbox oil heats up when it's working harder like when you are towing up hill in higher gear but is ok on flat roads like the M5 etc....

 

It certainly does. When you manually lock a lower gear with an auto, the engine revs are higher and you are in the power band. The engine is still working hard up the hill, and the water radiator (auto tranny radiator, is fitted) are pumping away, but by keeping your speed down a bit until over the hill is not too hard on the vehicle components.

If you leave the selector in Drive, the auto will change between gears, trying to find the appropriate gear to drive the vehicle, the tranny fluid will heat up faster and get to the point where the heat build up will cook the fluid. When the fluid is cooked, it loses it's ability to cool the tranny and the gears will start slipping, and this causes more internal heat and then The End of the transmission. A lot of money to repair the tranny.

Flat roads can still cause a problem by towing a large trailer/caravan continuously. Driving into strong headwinds also increase the towing effort.

When I towed my van across the Nullarbor, I waited until I had a tailwind both ways for several days. Those heading against the wind told me it was quite an effort on the tow vehicle, speed was below their normal towing speed, and fuel economy jumped markedly.

[kingfishbig]

With an auto you can tow in performance mode and this should lock out the overdrive gears, as well as holding each gear for longer. If you look in your owners manual you will usually find this recommendation.