ML430 differential fluid
 

Took the truck off-road last week and used 4x4 for about 15 minutes in moderate mud. Now I have a "whirring" sound at low speed that coincides with pressing/releasing gas pedal. Goes away at higher speed and rpm. Also makes the noise in park/neutral. Is this a differential issue. Truck has 147k, is it time to replace differential fluid?

Differential would make noise only while moving.

Would make sure that trans fluid was OK.

MB originally said that the trans fluid was "lifetime" fluid, until people started having problems. No harm can be done by changing the fluid and filter. Most people do it every 75-100k. To do it diy the trick is that the dipstick tube has no dipstick. So, you either need to buy or borrow one (they are not cheap) or, when you drain it, measure how much you drain, and then fill it up with the same amount.

You want to use the true MB branded stuff for this change.

Oh, and yes, you should change the diff fluid too.

All fluids should be changed. There's no such thing as "lifetime sealed"....MB even later withdrew this statement.

Thanks guys, much appreciated!

Does anyone have any official documentation from MB recanting the not requried "lifetime sealed" transmission fluid service.

-Kevin

Just like all things MB, they didn't recant...what they did do was suggest that starting in 2004 all transmissions from there on need a service 1 time at 39K.

Then starting with the 2009 models they REQUIRE trans service every 40K.

Guess the amount of money spent on transmission warranty caught up to them.