1990 300SE
Engine 103.981
Chassis 126.024

The fastlane website calls for 75/90W. Here is a copy/paste:

Note: 75/90W GL-5 Synthetic
Fully Synthetic Gear Oil - 1 Liter Fully synthetic multi-grade gear oil with a broad viscosity spread. Allows for easier shifting and quieter operation. Gives outstanding wear and corrosion protection. For manual transmissions, transaxles and rear axles where API GL-5 is specified. Please refer to owner manual for specific application! <-------I didn't see this part

I have put Mobile 1 synthetic 75/90W in and was reviewing the service manual AFTER I finished the job (real smart, huh?) and noticed that the service manual calls for 85/90W or 90. This differential does not have limited slip (I couldn't find the badge anywhere).

Am I OK using this 75/90W or should I drain it and use the correct weight. I can live with pouring out 8 dollars of gear oil, and next time I will read more carefully.

Michael C.