So I just picked up a transmission cooler for my 240. I'm going to be towing with it so I decided to get one to be safe. What are some people's solutions to mounting these on our cars? I'm wondering where the best spot would be and what sort of modifying would need to be done. Thanks!

 

your 240 likely already has a transmission cooler integrated into the radiator, there should be two transmission fluid lines to/from the right side of the radiator. I would cut into one of these, put two elbow fittings on it, run hoses from those elbows to your cooler, and mount your aux cooler low and in front of the radiator, behind the front air dam... thats where Mercedes puts them, anyways, and they are pretty smart about that stuff. hopefully you still have the plastic under-engine pan

a 240 will tow up to like 3500 lbs just fine within its power constraints, just be sure to switch off overdrive (so the OD up arrow stays lit), and if its hunting between 2-3, put it in 2nd til you're over the grade, or going fast enough for it to stay in 3rd.. its repeated shifting under heavy loads that kills a transmission.

of course, you need trailer brakes on anything over 1000 lbs, and you should subtract the tongue weight (typically 10% of the trailer weight) from your vehicles rated load (about 1200 lbs for a 2/7/9 wagon). note that vehicle rated load includes passengers and driver. I believe you need to use a leveling hitch if the trailer is over 2000 lbs, but your owners manual likely discusses this.

 

Cool! Sounds pretty easy! I have the IPD OD bypass plate installed so hitting the OD button is not an option. I installed the Moog Cargo Coil springs on the back and have about 1,000 miles on new shocks and struts. I will see how the rear shocks perform as is before thinking of putting something like Bilstein HD shocks on it. I'm pulling a pop-up camper, so at most probably about 2,000 pounds completely loaded. I just want to get the cooler on in the best spot possible so it is as effective as it can be. Thanks for the advice!

 

Any ideas as to how to wire up the camper for trailer lights?

And I will do the whole trailer brake thing. I know these things have really solid brakes stock, but I'm not taking any chances on it.

 

towing with OD will destroy your transmission in short order. first mild grade you hit at freeway speeds it will be 3rd/4th/3rd/4th, and do that over and over til it goes 3rd/crash

 

for simple 4-wire trailer ligths, get a universal trailer light converter, I've used the ones from Hopkins, and you connect the converter to power, one brake light, one parking light, left turn, right turn, and it converts it to the 4-wire system where the left and rigth brake lights ARE the turn signals. I usually install this near the spare compartment, left side of the trunk just behind the tail light.

something like Tail Light Converter with 4 Wire Flat Extension

I'd highly recommend using LED lights on the trailer (lower power) and if so, then you can power the converter from the handy power at the radio antenna, otherwise you'll need to run a power wire from the battery.

 

So if you had the bypass plate on your car and you wanted to tow, what would you do to compensate?

 

I would replace the OD solenoid, and fix the control circuit. or if the control circuit is hopeless, wire the solenoid to a toggle switch to ignition switched power (circuit 15) such that the solenoid is powered if the car is switched on, unless you flip that switch off. switch the OD off for towing, and on for normal use.

 

Hmmmmm... I see your point. I'm sure I can make that happen fairly easily, I just hate the whole push-button OD thing.

Just a side note question. Is the AW-71 transmission better for towing than the AW-70? I have a torque converter starting to go out on my AW-70 anyways and if I have to have the transmission pulled anyways, and I know I am going to be towing with the car, would it be worth having my shop drop an AW-71 in it or no?

 

having a shop change the transmission will likely cost more than the car is worth.

the AW71 is a heavier duty version of the transmission, but it still won't like shift-hunting while towing.