I am going to be replacing the differential fluid on several of my cars using Mobil 1 75w90 synthetic. However, I've noticed that some instead opt for Mobil 1 75w140. What's the case to be made for the higher viscosity fluid? What are the advantages and disadvantages?

In this area I'm a "lube newb"....just want to benefit from others' experience.

Thanks.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 178k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 75k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife