Manual vs Auto Fuel Consumption Offroad

Hi BwwB

I have had 2 of the same cars and run them together - Thirsty Patrol 4800 petrols , one manual and one Auto.

There was a clear substantial difference - The manual was better in the bush and slow
stuff whereas the auto is actually better on a highway cruise by about 6%.

You can predict this by checking for lower engine RPM at your cruising speed (95kmh for me).

I did the Canning in the manual for 18lt/100km whereas a troppy V8 diesel with me used 14.7lt/100km

The manual has the ability to have its revs momentarily drop way down whereas the auto swaps up a gear and revs and friction losses increase.

Also done Madigan and other slow tracks and mostly you just idle along 1000 - 1500rpm and use little fuel in the manual.
The Canning though is an easier faster track probably mostly 40kph.

Have been working to make the auto as good as the manual and recently had gearbox hotted up so that it spends less time in the torque converter , seriously works better in the sand but to early to get overall consumption figures.

I have a 150 D4D GX manual. I averaged spot on 14L/100km for the length of the Canning and averaged 12.6 L/100km over the entire 10,500km trip. these are real, measured numbers not what the in-dash display says.

I don't have any auto figures to compare to.

In terms of reliability I don't think there's any known issues with either gearbox on the Prado.

I'm about to head off across the Simpson and back across Madigan line so will be able to provide more figures in a month or so.

The Prado is a good vehicle but IMHO your HZJ105R is much better for the tough going and has more room. But on the other hand the Prado is probably much more comfortable and will be better for highway running. I don't think you will notice too much difference between either the auto or manual .....frankly I'm getting a bit slack in my old age and now prefer the diesel/auto combination for both off road and on road driving.

I have heard of heat build up being quite significant in many autos in soft beach sand & Simpson Desert crossings especially if left in high range.
Is a transmission cooler advisable?
Does one have to stop regularly to allow the auto to call down?

I think when you are in the sand, dirt, x cty and 4wdg the manual is hard to beat. You can look ahead select the correct gear for the job, apply the revs and be comfortable that you have control of the vehicle and situation.
Manual diesel for me!!!
My thoughts

Regards Will