Hi Moregoodstuff,
Yes have replaced all the fluids in the sprinter except the hydraulic fluid used in the sprintshift gear control.
The gear oil I used is the MB 235.10 Schaltgetreibeol A001 989 2603. In NZ the only stuff available which is certified by MB. It is expensive, $52 NZD /litre and you need 1.5 litres So you have to buy 2 litres. This works out to be about $10/year on change every 10 years or 300,000kms. Do not use any other substitute oil. It is not just worth it. The cost of repairing/ replacing the transmission is huge compared to the cost of the oil.
To replace the oil:
1. Find the reservoir on the right side of the gearbox housing. It is held in place with a C clamp and two bolts. Remove a third bolt at the bottom front of the reservoir.
2. Pull out vent bleed connection on reservoir and swing the assembly away towards the back.
3. The oil filler plug can now be seen behind where the reservoir was.
4. Clean around the plug before removing. 14mm hex key plug is required.
5. The oil drain screw is found underneath. Remove and drain oil when oil is warm.
6. Remove metal particles off the drain plug. Screw in drain plug. Torque to 60Nm.
7. Fill with transmission oil.
8. Check the oil level with an allen key inserted into the oil filler hole and ensure that the oil level is exactly 10mm below the bottom edge of the oil filler hole. Do Not overfill. (and don't drop the allen key)
9. Screw in the filler plug. Torque to 50Nm.
10. Reposition pressure reservoir, Oil vent bleed connection. and screw in the single bolt removed in item1. Do not tighten.
11. Position C clamp on reservoir and tighten all three bolts to 15Nm.
12. Arrange for Significant Other to make a cup of tea while cleaning up!
Cheers
Ross