I'm not sure if you are aware of this - the dip stick for these transmissions is supposed to be "MB shop only" so you won't find one living underneath that cap. I bought one awhile back but it would be pretty easy to make one.

If I were you I'd be 100% certain that you do not have a fuel leak from some bad O-rings on/near the IP that would be the cause of your mileage issue. I get roughly 32-33 mpg on summer blend D2 (all highway @ ~75mph).

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Scott C.

2006 E320 CDI (120k miles)
FOR SALE: 1998 E300 Turbo Diesel - Black w/Tan Leather - Euro delivery (236k miles)