Pajero Owners Club of South Africa

Bigwill wrote:Ok well so lets agree to disagree. In any case I do not like to stand with my legs spread apart.
I can tell you that in my days of racing I never broke a gearbox while in the higher ratios, but in first and second I did.

driving gear or driven gear?

4EPikinini asks

driving gear or driven gear?

In the cases I am referring to it was normally the cluster gear and the cog for the specific ratio that goes. I suppose that is both "drive" and "driven". The reason obviously is because you are running more power and have faster accelarion from high engine rev's in 1st and 2nd.

The point I am making is that the presence of a caravan does not allow more torque onto the transmission than what would be normally the case when accelarating up a hill in solo. The enjin does not become more powerful because there is a caravan on tow. However you do generate more power when changing down to 4th and that can load the transmission more.To me the overall impact of driving the engine at unneccesary high revs by far exceeds the very minor effect that 5th gear puts onto a single cog.

Very interesting discussion. Thanks for sharing your views.

Bigwill wrote:4EPikinini asks

driving gear or driven gear?

In the cases I am referring to it was normally the cluster gear and the cog for the specific ratio that goes. I suppose that is both "drive" and "driven". The reason obviously is because you are running more power and have faster accelarion from high engine rev's in 1st and 2nd.

The point I am making is that the presence of a caravan does not allow more torque onto the transmission than what would be normally the case when accelarating up a hill in solo. The enjin does not become more powerful because there is a caravan on tow. However you do generate more power when changing down to 4th and that can load the transmission more.To me the overall impact of driving the engine at unneccesary high revs by far exceeds the very minor effect that 5th gear puts onto a single cog.

Very interesting discussion. Thanks for sharing your views.

I can't put my thoughts into words but would love for the more tech savvy guys to give their input. This is the kind of discussion that I love.

This is the kind of discussion that I love.

so do I.

Consider the impact of driving voluntarily in 4th as apposed to 5th:
More noise
More engine wear.
More fuel used.
More heat generated.
Potentially more kick to the teeth of the transmission.

Staying in 5th.
Undefinable extra load on one cog.

Well

You guys are making this a very technical discussion. My experience is this:
I tow my, very heavily loaded, Xplorer caravan in fifth all the time and go down to fourth once the revs fall to just above 2000rpm. This gives decent fuel consumption and power. I now have 220 000km on and recently had the box open for new retaining plate and first and third gear selector fork, so it did not seem to do harm to the 'overdrive' gear. This is on 2001 3.2Did incidently.

I ussualy tow at around 120km/h and at that speed 4th is definately not gonna be nice.

CATS

The only thing I have ever towed is boats, but my experience is that you choose the correct gear to suit your ideal rev range, whether you are towing or not.

I think the message here is not to let the engine labour, running in 5th with a load on the back is one thing but having a caravan that not only adds to the weight but has a considerable amount of wind resistance does tend to load the final gear more than one would like. On the level areas and downhill sections I can see no problem but as soon as the engine starts working hard rather shift down, fuel is cheaper than a gearbox.

Here is my take on the issue (and I’m not nearly technical at all):
The car in question (which incidentally did the Hartenbos trip like a dream) is a tiptronic DiD.
1) Every engine has an ideal rev range. On the DiD I found that anything from about 1500rpm is very useable and from 2000 to 3000 is where most of the work can be done. Above 3000 revs is high and should only be used for short bursts. When towing a heavy load, I preferred to stick to the 2000-3000rpm range.
2) The gearbox (5th gear) discussion has been around for decades. Most 4x4’s (and all Pajeros, I think) have a direct drive 4th gear. I have no doubt in my mind that the direct gear will last the longest. So if you are concerned about the gears in your box not being reliable, then surely 4th is the gear of choice when towing a heavy load. The Pajero does not have a suspect gearbox, so I see no need to “force” the auto box into a gear it would not have chosen out of free(computer) will.
3)The torque converter also comes into the equation. We can all see when the box disengages the clutch and puts the drive through the torque converter. It is shown by a step-up increase of about 200rpm. I think it is prudent to not tow a heavy load for hours on the torque converter on a hot Karoo afternoon, into a strong wind. When conditions get that bad, I would slip the tiptronic to 4th, and maybe drop my speed to 100km/h.
4)Fuel cost on a multi-thousand kilometer holiday is a considerable sum. If you do not have to incur a 10% “penalty for running in 4th, then why do it. The fuel consumption read-out on my current 3.8V6, shows a 2litre/100km increase in consumption in 4th as opposed to 5th at 100km/h with a heavy load in tow.

My personal choice is to leave the car in auto mode for most of the trip. I found that the box will select 4th without too much ado, so there is no need for me to interfere.

I am also no expert, but can recall two incidents:

1) My dad used to tow a Jurgens Exclusive with the old VW with V6 Ford motor. The 4th gear packed up (it only had 4 gears) and the advice from the mechanic was to change down whenever the revs fell to 3000rpm. Normal cruising was still done in 4th. "Don't let the engine labour" was his instruction.

2) Customer of ours used the deliver meat to Jhb from Welkom. He used an Isuzu bakkie with a heavy loaded trailer. Gearbox kept on packing up on both the bakkies. He also got the advice not to drive in 5th gear. Problem solved.

As said before, I am no expert...

There was no way that the vw gearbox could handle the torque of the v6 motor and if you dared to hook a caravan behind it disaster was the result if you dared going to top and expeting the engine to work a bit.