Making sure I have good maintenance baselines on my newly-acquired E250 Bluetec 4Matic. No record of the rear diff fluid ever having been changed, so will do that ASAP.

Curiously, there is no recommended maintenance for the front diff. And the shop foreman at my local MB dealer claims that it is "non-serviceable" on my model.

Now it is clearly more difficult to replace the front diff fluid as there is a drain hole BUT NO FILL HOLE. You either have to remove the axle or employ this method:

https://www.youtube.com/watch?v=JM4yjivFn3w

But what I'm wondering is this: why does MB have a regular interval for the rear diff (40k miles) but assume/imply that the front never needs to be touched? Put differently, why wouldn't MB want to change the fluid since it's clearly something they're capable of doing and could charge the customer for?

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife