Mazda B, UN (USA / CAN)

Automatic transmission fluid capacity & service interval

Mazda B, UN (USA / CAN) requires automatic transmission fluid with a capacity range of 9,4 to 9,8 liters. Service intervals include checks at 30000 miles or 24 months and fluid changes at 30000 miles or 150000 miles. The data covers 10 configurations.

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

TypeSpecifications
B 2300 (2003-2007)
  • Use: Normal
  • Capacity 9,4 liter (Dry fill)
  • Check 30000 miles/ 24 months
  • Change 150000 miles
  • Code: 5/1
B 2300 (2003-2007)
  • Use: Severe
  • Capacity 9,4 liter (Dry fill)
  • Change 30000 miles
  • Code: 5/1
B 3000 2WD (2003-2007)
  • Use: Normal
  • Capacity 9,5 liter (Dry fill)
  • Check 30000 miles/ 24 months
  • Change 150000 miles
  • Code: 5/1
B 3000 2WD (2003-2007)
  • Use: Severe
  • Capacity 9,5 liter (Dry fill)
  • Change 30000 miles
  • Code: 5/1
B 3000 4WD (2003-2007)
  • Use: Normal
  • Capacity 9,8 liter (Dry fill)
  • Check 30000 miles/ 24 months
  • Change 150000 miles
  • Code: 5/1
B 3000 4WD (2003-2007)
  • Use: Severe
  • Capacity 9,8 liter (Dry fill)
  • Change 30000 miles
  • Code: 5/1
B 4000 2WD (2003-2007)
  • Use: Normal
  • Capacity 9,5 liter (Dry fill)
  • Check 30000 miles/ 24 months
  • Change 150000 miles
  • Code: 5/1
B 4000 2WD (2003-2007)
  • Use: Severe
  • Capacity 9,5 liter (Dry fill)
  • Change 30000 miles
  • Code: 5/1
B 4000 4WD (2003-2007)
  • Use: Normal
  • Capacity 9,8 liter (Dry fill)
  • Check 30000 miles/ 24 months
  • Change 150000 miles
  • Code: 5/1
B 4000 4WD (2003-2007)
  • Use: Severe
  • Capacity 9,8 liter (Dry fill)
  • Change 30000 miles
  • Code: 5/1

Additional Notes

  • All dry fill capacity figures across the Mazda B-Series (UN) 2003-2007 automatic transaxle configurations fall between 9.4 and 9.8 liters, which is consistent with a complete drain-and-refill of the entire transaxle assembly rather than a partial service top-up.
  • The B 2300 carries the smallest dry fill capacity at 9.4 liters, while both the B 3000 2WD and B 4000 2WD share an identical 9.5-liter figure, placing them between the 2300 and the 4WD variants.
  • The 4WD configurations of both the B 3000 and B 4000 share a dry fill capacity of 9.8 liters, which is 0.3 liters greater than their respective 2WD counterparts, reflecting the additional fluid volume associated with the transfer case or extended drivetrain components integrated into the transaxle assembly.
  • Under normal use conditions, a fluid check interval of 30,000 miles or 24 months is specified across all configurations, meaning whichever threshold arrives first would apply.
  • The normal-use fluid change interval is set at 150,000 miles for all configurations, a figure that represents an extended-life service schedule typical of modern sealed or semi-sealed automatic transaxle designs.
  • Under severe use conditions, the change interval drops to 30,000 miles across all configurations, which coincides with the same mileage figure used for the normal-use fluid check interval, though the two serve distinct service purposes.
  • No fluid check interval is listed under severe use conditions for any configuration, meaning the severe-use schedule specifies only a change at 30,000 miles without an intermediate inspection point.
  • The drivetrain layout, specifically 2WD versus 4WD, produces a measurable difference in transaxle fluid capacity within the same engine family, as seen in both the B 3000 and B 4000 pairings across the 2003-2007 model years.

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