Mercedes-Benz Unimog (EU)

Transfer case fluid capacity & service interval

Mercedes-Benz Unimog (EU) transfer case fluid capacity ranges from 1,4 to 6,25 liters. Service intervals include checks at 200 hours or 4000 km/200 hours, and changes at 15 hours or 12 months/400 hours. The data covers 5 configurations.

The configuration chart below lists fill volumes and service intervals for each engine and trim variant.

TypeSpecifications
416, U 125 (1977-1988)
  • Use: Normal
  • Capacity 1,4 liter
  • Check 200 hours
  • Change 12 months/ 400 hours
416, U 125 (1977-1988)
  • Use: Initial service
  • Capacity 1,4 liter
  • Change 15 hours
425, U 120 (1977-1984)
  • Use: Normal
  • Capacity 6,25 liter
  • Check 4000 km/ 200 hours
425, U 150 (1977-1988)
  • Use: Normal
  • Capacity 6,25 liter
  • Check 4000 km/ 200 hours
421 (1970-1988)
  • Use: Normal
  • Capacity 1,4 liter
  • Check 200 hours

Additional Notes

  • The Mercedes-Benz Unimog (EU) transfer case fluid capacity splits into two distinct groups across the listed configurations: the 416/U 125 and 421 variants hold 1.4 liters, while the 425/U 120 and 425/U 150 variants hold 6.25 liters, a difference of nearly 4.5 times the volume.
  • The 6.25-liter capacity on the 425-series configurations is consistent across both the U 120 (1977-1984) and U 150 (1977-1988) variants, indicating a shared transferbox/p.t.o. assembly despite the differing model designations.
  • For the 416 and U 125 under normal use conditions, the check interval is set at 200 hours and the change interval is defined as 12 months or 400 hours, whichever comes first, reflecting a dual time-and-calendar-based service schedule.
  • Under initial service conditions, the 416 and U 125 transferbox/p.t.o. carries a change interval of just 15 hours, a significantly shorter interval compared to the 400-hour normal use change interval, consistent with the practice of removing break-in contaminants from a newly serviced unit.
  • The 421 (1970-1988) specification lists only a check interval of 200 hours under normal use, with no change interval recorded, while the 1.4-liter capacity matches that of the 416 and U 125 configurations.
  • The 425-series check interval is expressed as 4000 km or 200 hours, introducing a distance-based threshold alongside the hourly one, whereas the 416/U 125 normal use interval references only hours and calendar months with no distance figure.
  • The 421 configuration covers the widest model year span in the dataset, running from 1970-1988, and shares the 1.4-liter transferbox/p.t.o. fill volume with the later 416 and U 125 models introduced from 1977 onward.

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