Techniques for towing vans up hills

[&Roo]

We’ve just driven some pretty mountainous country from Melbourne to Ballina via Dargo, Jindabyne and Tenterfield pulling a 2.5T van with our Auto 2013 NW.

Following the wisdom on this forum, we’re towing in 4H, 4th gear. Open road towing has been easy, but no surprises the Paj has struggled with a few of the hills.

I’m worried some of this is driver error from not selecting lower gears early enough and would love to know other drivers’ techniques for hills.

I’ve been aiming for good speed at the base and then to maintain 2500-3000rpm through the climb. Typically this means a change down to 3rd at 80-90kph (on the dial) peaking at a little over 3000rpm or the revs drop straight to low 2s and the speedo dives.

A couple of monsters have required another shift down to 2nd at around 50kph on the dial and a lot of encouragement.

(I don’t have any gauges ATM but have been reading the forums and know an ultragauge should be a priority on my eBay shopping list)



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[Pwoffey]

I don't see that there's much you are doing wrong. If you had a Scangauge or Ultagauge etc, then I suspect you would change down a bit earlier as you see the ATF temp climb (and it does so very quickly). But at the end of the day you are asking a 4 cylinder 2.25T (kerb wt)/3T (fully loaded) tug to haul a 2.5T (loaded wt?) van up some long hard hills. It's not going to be zippy.

[spot01]

As mentioned, this usage results in very high ATF temps, which dramatically shortens the life of the fluid.

For heavy towing, the handbook shows ATF should be changed I think every 90k (check the book). Depending on history & kms, might be worth considering a change now - then you will know its good. Be sure to use the correct fluid (genuine if in any doubt) - its expensive, but transmissions are much more expensive. Note there are a few other service items that need to be done more frequently if doing much heavy towing, eg, oil/filter, etc (refer handbook).

[Dicko1]

Maybe aim for 2800-3400. That way as it starts to lose momentum it still has a bit more torque to use. A nearly 3 tonne brick pulling another 2.5 tonne brick up a hill is never going to be quick, let alone easy. Dont be afraid to use 3rd gear. Maybe try lighten the load as much as you can too.

[NTBenny]

My recent exposure to towing a 2.8T van at Xmas had me constantly watching intake and transmission temps via my Scangauge. An unlocked converter quickly results in transmission temps approaching 110deg. With the converter locked I didn't see much more than 85deg. Intake temps can also quite easily hit 100deg. The other worrying temp is EGT. On big hills I was constantly seeing 600deg which is not good. I'm hoping to improve all this in the coming 6 months with an M&M Lockup, intercooler and possible tune.

As said above towing a big van is a lot to ask for a little 3.2L Paj. I estimate my weight to be 5.6T fully loaded.

Benny.

[CATs 4x4]

My recent exposure to towing a 2.8T van at Xmas had me constantly watching intake and transmission temps via my Scangauge. An unlocked converter quickly results in transmission temps approaching 110deg. With the converter locked I didn't see much more than 85deg. Intake temps can also quite easily hit 100deg. The other worrying temp is EGT. On big hills I was constantly seeing 600deg which is not good. I'm hoping to improve all this in the coming 6 months with an M&M Lockup, intercooler and possible tune.

As said above towing a big van is a lot to ask for a little 3.2L Paj. I estimate my weight to be 5.6T fully loaded.

Benny.

Benny

I don't think 600degC is too much for EGT in those circumstances, dependant in where the probe us situated. My reading on the matter has indicated that below 700degC is all good, so 600 is still well within usage limits I would think. Crazy high when you think of it, but still acceptable.

CATS

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[NTBenny]

Yeah problem is my probe is about 50mm off the back of the turbo in the dump pipe so I've taken 100deg off as a maximum.

Benny.

[&Roo]

Thanks @pwoffey, @spot01, @Dicko1, @NTBenny - that’s been reassuring. Have ordered an ultraguage and will try to use this to ensure I’m being as kind to the auto as I can while towing


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[Boo Boo]

I have installed a temp guage at the oil outlet from the transmission to the cooler so we are getting accurate temps
The speed at which the temperature increases amazed me and changing driving style has an enormous effect on the temperatures.
I even found out that coasting down a hill in 5th gear increases oil temp fairly quickly.
Towing a 2 ton van on a flat road in 4th gear oil will be around 80 degrees and any slight incline will see the temps rise pretty quickly.
Really happy we installed ours.
The next thing will probably be a torque convertor lock up kit just waiting on MM 4x4 to develop it for the NS.

[Rovingman]

I tow 2t and use 2nd and 3rd alot. Keeps the trans temp down considerably. With my oversized tyres i use 4th regularly just driving around.

[Luke68]

Lock up converter

Can someone please clarify. My understanding was that when in sport mode all the gears were in lockup up. Am I wrong? If they're not locked up, what's the point of sports mode? And having to get a separate lock up kit is wasteful.
Cheers
Luke

[Pajshomoneroguntero]

Can someone please clarify. My understanding was that when in sport mode all the gears were in lockup up. Am I wrong? If they're not locked up, what's the point of sports mode? And having to get a separate lock up kit is wasteful.
Cheers
Luke

Yes, you’re wrong to believe sports mode locks the tc. The tc will lock when the computer says so given certain parameters being met. The lockup kit, be it a manual style like the Wholesale Automatics or a fully automatic version like M&M’s Lockup Mate, can engage the tc lock earlier and hold it for longer.

The auto in auto mode always chooses a gear too high than optimum for the situation. So the point of sports mode is to regain some control over which and when a gear is selected.

To say that a lockup kit is wasteful seems an off the cuff comment. For instance I can already see around a 1L/100km fuel burn saving using Lockup Mate.

[old Jack]

Hi Luke,

On the Gen 4 NT onwards the Aisin 5 speed auto trans is fitted, it has an electronically controlled torque convertor dampner clutch lockup in 3rd, 4th and 5th gears only. When the trans is in "D" the AT ECU tends to select one gear higher than what is really required so the TC does not lockup in most load conditions. If driving in manual mode and selecting the correct lower gear the TC will lockup if all the conditions are correct, problem is when the conditions change and the TC unlocks and the driver does not manual change down a gear. This results in the unlocked TC slipping and generating heat really fast so the ATF temps skyrocket, the problem is the ATF temps do not decrease as you go down the other side of the hill as the AT ECU unlocks the TC so the TC continues to slip.

Fitting a lockup kit and using it correctly when in manual shift mode will result in lower ATF temps and reduced fuel consumption.

There are 3 TC lockup kits that are available from;
1. Wholesale Automatics, this is PWM controlled electronics and 100% driver controlled.
2. Richards Auto, this is PWM controlled electronics with speed sensitive "off" control, so you can't forget to disable it but you still have to select it "ON"
3. Lockup Mate by MM4x4 is PWM controlled electronics with speed, engine load and accelerator position sensing to both engage and disengage the TC lockup fully automatically for the gear you have selected? Just turn it on and as soon as you start using manual gear shifts it will lock and unlock the TC without bypass the factory projections that the AT ECU provide. This is the newest and best option, developed by forum member M&M. It is also the cheapest of the 3 kits available.

OJ.

[Flying]

Please make a lock up mate for the PS next M&M!

[old Jack]

Please make a lock up mate for the PS next M&M!

The 8 speed Aisin auto in the Pajero Sport, already locks the TC in 3rd, 4th, 5th, 6th, 7th and 8th gear and the TC lockup operational profile is quite complex so it could be very difficult to do a Lockup-Mate for this auto trans, it may not even be possible at all.

OJ.