belac350

Hello, all new to the the MB world, so far so good. Picked up a 2009 ML350 with 28k on it.

Just did an almost complete service, oil change, plugs, air and cabin filters, belt, rotate tires, just wanted to start off fresh.

One question on the transmission. I want to add a cooler, I have always added one to my other cars with great luck, but this one is different. I understand no dipstick, fill when its up to temp, but if I add the cooler, how will that affect the fill level at temp? Fluid expands with heat, but the cooler will help that, but the car will not be moving. Am I making sense, someone add to this, Thanks

venchka

Welcome aboard.
I understand your desire for an aftermarket cooler. A couple questions come to mind:
1. How much capacity does the OEM cooler have? It may be sufficient.
2. Will the software for the transmission tolerate tinkering with the cooling circuit?
3. Hopefully someone has done this and will give you the straight scoop.

Wayne

belac350

I just have a problem with the factory cooler, cooling 190F ATF with 210 coolant just does not seem correct. It works, but any amount you can cool ATF the better.

Moto One

Up to a point, but there is a proper operating temp and when it flows into the factory cooler it's much hotter then 190F. Now if you are towing at max GVW for long distance adding a thermostat controls aux cooler would help control temp.

Mark.

sosh

No additional cooler required or needed. In fact it may foul up some functions. Have heard of no transmissions overheating even towing heavy trailers. My suggestion leave it alone

AudiA4Turbo22

Correct, transmission fluid needs to get up to proper working temps to work properly. A trans cooler would make heating up the fluid much tougher on the trans.

dgiturbo

Belac350, as said before, LEAVE IT ALONE.
These transmissions are very technical, and requires a computer to properly refill the tranny. You will notice no dipstick, and it also takes a special fluid.

With 28K miles and a new purchase, I would take it to a dealer and have the tranny fluid and filter replaced. This is recommended at 39K miles, but as you don't know the history and want to start fresh, jump the gun here. While it's there, have them update the tranny software.
Then drive , and make sure you have an extended warranty.
$7500 for a tranny job, IF you can find a rebuilt one.
Otherwise, enjoy the ride.