Well, I haven't done it with the 6 cyl diesel in the 2007 ML-320 CDI but I have pulled a 3,000 lb trailer (coleman popup) with a Sprinter which has the 5 cyl MB diesel and it pulled it without any problem.
I would guess the ML-320 CDI would be the perfect vehicle to pull a trailer with taking into account the diesel and all wheel drive.
Only got my ML320 in March and I towed with it for the first time last week.
Towed a trailer with mini excavator weighing 2700kg about 90 miles. Tows like a dream, its stable at 60/70mph and the 320CDI has plenty of power.
Prior to the ML I had a long wheelbase Mitsubishi Shogun Diesel with tiptronic 5 speed auto box. The car was stable when towing but massively under powered (about 160 bhp compared to the ML's 220). Its main problem when towing was the auto box constantly changing down to 4th and then back to 5th on anything but a level road. Not enough power/torque in 5th but it wouldn't hold in 4th so I found myself manually holing it in 4th most of the time which had a significant effect on fuel consumption.
No problem at all with the ML, It holds onto top gear when towing on all but the steepest steep inclines.
As a bonus it also does about 10mpg more than the Mitsubishi.
Thanks for the response. This is exactly what I wanted to hear. So it sounds like that would be approx 5500lbs or so right? Where you towing in fully automatic or manually holding 5th or 6th gear? It sounds like it made plenty of torque for you to tow this weight and what I want to tow hear in the US is about the same.
dieselfan: I was towing in fully automatic. After the first 10 miles or so the auto box settled down and was able to hold 7th gear almost all the time, only changing down for fairly steep inclines.
Although it doesn’t look it, the ML320 is only a few millimetres smaller than my old Mitsubishi and a few kilos lighter, but it has about 25% more bhp and 30% more torque and this really makes a huge difference when towing. I also have airmatic on mine, which helps with stability etc.
Fuel consumption and emissions are also an issue here in the UK, with diesel costing almost £1 / $2 a litre (over $7 for a US gallon!) and the new car tax based on emissions we have recently been blessed with (ML320 = £300 / $600 per year). The ML has far better fuel consumption and emissions than the Mitsubishi, so over 3 years at 20,000 miles per year, I should get back most of the extra cost of the ML.
I am excited from your answer. Being able to tow that kinda of load in not just overdrive but the 2nd overdrive (5th gear is 1:1) is amazing. I have approx the same load to tow that you are towing and only need to tow it on secondary roads mostly at a top speed of 55mph. I was just hoping to be able to maintain 55-60mph in 5th but sounds like it will accelerate from this speed and load.
I don't envy your fuel prices as I am only paying approx 2.75-2.85/ gal here in Georgia.
Thanks for the replies
I also have heard that you always tow in drive but I think that this has alot to do with domestic transmissions torque converter lock up strategy... I have read some articles on the mercedes trans have torque converter lock up from 1st gear on but nothing has been written that I have read about towing with the 7 speed. Since I haven't received my 320cdi yet (yet being the key word). what does it say in the owners manual about towing????
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