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Discussion Starter · #1 ·
Hi All,
I am just about to take delivery of a new van.
My old van was 1400kilos and was easy to tow. I travel froom Adelaide to WA and normally sit on or around 100ks/hour.
Now I have the heavier van what would be your suggestions about towing style.
Should I drive say on a flat road with O/D on or Off. It seams to rev very hard when O/D is active 2400 rmp, compaired to 3100 rpm not active. I dont use the lock or hold button(not sure which it is).
Can you suggest the methods I need to use to get best power/ fuel economy. Have a Tunit chip fitted.
It feels around 80 k/h changes to 4th, then around 95-98k/h changes to o/d.I would like to hold it in 4th but when I turn off o/D revs go sky high?????

I hope i am not to unclear as this is all new to me.

Thanks in advance
 

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nissan patrol Gu6
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tare or atm?

Is the vans tare weight 2.4t or its atm? The auto is only rated to tow 2.5t. If its the atm it doesn't leave much room for error.
 

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Discussion Starter · #3 ·
Hi , Its Tare Weight - 1696 Kg, Size - 15 Ft, ATM - 1996 Kg. I have changed a few things like duel battery's, duel tanks and 6 " frame so will be slightly heavier than this. Sorry for not mentioning this from the start.
Cheers
madmax800
 

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ZD30 Out - L77 In!
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Hi madmax800,
The hold button only holds the transmission out of 1st gear, so not an option when towing. Using power mode should make it kick down at lower speed than not using power mode, so I would think that just leaving the switch in the middle (Auto) would be your best option when towing.
Your 4th gear is overdrive and what you feel at 95-98k/h is the torque converter locking. I would strongly suggest that you try to tow with the torque converter locked as often as possible to reduce the chance of your transmission overheating. Your converter should lock in 3rd gear at 90km/h also, but unfortunately when you go from 4th back to 3rd, the converter unlocks which can be annoying. Towing heavy loads in O/D can be detrimental unless the converter remains locked due to the excess heat generated in the transmission, which is why the auto has a lower towing capacity.
 

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Discussion Starter · #5 ·
OK,
So if time was not an issue would I be best to tow in o/D off (higher revs) and sit on around 90 K/H or try to get up around 110k/h with O/D on and lower revs or is there a simple rule, say 90 have O/D off and rev faster and over 100 have O/d on (lower revs) but then switch off O/d on hills and let engine rev harder.???? hope you can understand my meaning. Thanks
 

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ZD30 Out - L77 In!
nissan patrol
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It all depends on the ability of the vehicle to pull the weight, the weight and the terrain you are travelling over. I don’t think that towing in 4th is an issue, but I would shift back to 3rd going up hills even if it means slowing down a bit to reduce the load on the engine and transmission so that the converter stays locked for as long as possible. When towing with the auto, it pays to keep the revs up a bit under load so that the transmissions pressures are high enough to reduce the chance of the clutches slipping.

Unlike many other 4 speed transmissions, the Jatco trans used in the Patrol doesn’t automatically lock the converter in 4th which is their downfall and the main reason why their load rating is so low. Driving in O/D with the converter unlocked generates a lot of heat in the transmission, particularly when towing heavy loads up hills. There is a simple solution which makes the car and transmission much better for towing, by fitting a manual converter locking system.

I normally only tow just over a ton of camper, but with the converter manually locked, it stays locked until I decide to unlock it. This gives me the ability to hold the transmission in 3rd gear up to around 100km/h at 3000rpm. I rarely shift into 4th below 90km/h and at 100km/h in 4th I’m doing 2000rpm. Then while towing the camper, I just shift between 3rd and 4th and keep the converter locked. I can do this at speeds between 60 and 110km/h and the transmission runs at around 80 to 90C instead of 110C +. Also if you do a lot of heavy towing, consider using Castrol TransmaxZ when you next do a transmission service. Fully synthetic transmission fluid has much better heat tolerance.
 

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Discussion Starter · #7 ·
Hi Chaz, Thankyou for your time and understanding on this.

I will do some home work on looking up info on the transmission locker.

Regards

madmax800
 

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Autos are Superior
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Look at a transmission temp gauge, and possibly extra external PWR oil coolers as extra insurance.
 

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I just sold my 2003 ZD30 Auto and towed my 2.5 ton boat everywhere.

Never had a heat issue, woudl always kick it back to 3rd going up hills, never used OD under 80km. Best fuel ecomony was Syd - Bris with foot 1/3rd Throttle, 15.5LPH. If I pushed hard at 110-120 was 19-21lph, normally around 16-19 between 90-110.

But now bought a TB48 so no problems :)
 

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Enemy of Reality
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Is the vans tare weight 2.4t or its atm? The auto is only rated to tow 2.5t. If its the atm it doesn't leave much room for error.
I thought the auto was rated for 2.8tonnes.
 

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You could up the tyre size a notch, that would drop the revs a bit so itll settle it down in third.
Im running 285s which seem to work reasonably well towing.
305s just killed it!
 

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The auto is rated to 2,800kg tow capacity. I am with truckster and would be fitting a front mounted transmission cooler if there's not one already there.

Other than that it should tow OK. There is a lot of debate with auto's and that sort of weight about leaving them in 3rd when towing. I always towed in top in my LR Disco but dropped it back to 3rd when going up hills well before it would have changed. 90,00 klms in the auto disco and about 30,000 of that with a van on the back.

With the sort of weight you are now talking about get a set of polyair springs fitted to the back coils otherwise it will be just about be sitting down on the ground. Also upgrade the shocks.

I easy have 2,500 kg on the back of my manual CRD when the Lotus Sprint 2 is on the back loaded up. I only ever tow in 4th gear, not 5th and get much better fuel economy.
 

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Hi Chaz, Thankyou for your time and understanding on this.

I will do some home work on looking up info on the transmission locker.

Regards

madmax800
a very non-technical explanation is...

an auto transmission has two main parts. Up front is a "torque converter". The engine drives this which is full of oil. The engine swirls the oil and the swirling oil drives the output shaft. This is what allows you to stop without throwing a clutch. If the engine is just idling and not swirling a lot of oil, the car can stay still. When the revs get up, the car wants to go.

After this on the Patrol is a 4 speed gearbox which shifts automatically.

Now when cruising along with all that oil swirling around the torque converter, a lot of heat is generated in the oil by friction. This makes the gearbox hot and wastes fuel. Since about the 1980's most auto transmissions have partially solved this problem by adding a lock to the torque converter which locks up when you are going fast enough. Once locked, the drive goes direct without needing that swirling oil, so the gearbox stays as cool as a manual box.

How to know when your converter is locked? When you start you will feel the gear changes 1-2, 2-3, 3-4, then provided you are fast enough, you feel another one - that is the converter locking.

I don't have an auto, but I think it will lock in 3rd gear too if you are fast enough and have the gear selector in 3. That is an efficient way to tow up a hill.

Some people modify the controls for the transmission so it will lock in at a lower speed. This is good for towing as it keeps the transmission cooler and saves fuel. Heat is the enemy of auto transmissions, hence the suggestions above for temperature gauges and extra cooling if you plan on pushing hard with a big load.

The patrol trans has a good rep as being a strong unit, but still heat can kill any auto transmission
 
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