Hello all,
I would like to put to use my recently retuned 4.5 to do some light towing. I emailed the MB Classic Center in CA and they told me the car as equiped has a tow rating of 750 kg, or 1650 lbs. I've read through the search on this site and notice some 6.9's have more than twice that capacity. What type of shocks/springs would need to be put on to keep the suspension from bottoming out as is? What I need to tow is about 900kg/2000 lbs. I know the power train itself could handle it with out even a hiccup as this old gal has alot of torque. Thanks.
The 6.9 has the higher rating mostly due to the hydro suspension, which keeps everything level [and of course that massive 6.9l motor]. A few 4.5 cars did come with SLS [hydro for rear end only], so if you have that, you are set. If not, then I would tread carefully....mostly due to the incredible leverage of the weight on the chassis....the towing tounge would be quite a way from the rear axle, yielding a lot of leverage and weight over it.
Fitting stiffer 'towing' rear springs and dampers will result in a serious downgrade in the car's handling.
prior to rebuilding my rear end, i had towed a 3000kg braked furnature trailer with my 6.9, while the engine dosent even feel the trailer being there, the rest of the car isnt built to handle those kinds of forces... I ended up with collapsed rear wheel bearings.. other than that it survived, but ill never do it again, it was an emergency at the time...
If the trailer is loaded correctly so that there is no weight on the tongue id see no problem towing a 900kg load. I'd feel alot better about it if the trailer had decent brakes though...
When towing in a 6.9 it feels like nothing is attached, but you know its there because the fuel gauge drops quicker than the speedo needle can increase ;-)
Expect to consume about 1 litre/km while towing in a 6.9
I.
I will take all this into consideration when making any final decisions for towing. Thanks for the input.