According to the 1999 Ford Ranger Owner Guide :
With engine oil filter change :
The 2.5 liter four cylinder engine and the 3.0 liter V6 engine take ( 4.5 U.S. quarts )
The 4.0 liter V6 engine takes ( 5.0 U.S. quarts )
For the 3.0 liter V6 engine in a 1999 Ford Ranger , with engine oil filter change : ( 4.5 quarts ) according to the Owner Guide
According to the 1999 Ford Ranger Owner Guide : For the 3.0 liter V6 engine : With engine oil filter change : ( 4.5 U.S. quarts of 5W-30 )
With engine oil filter change ( 5 quarts of engine oil )
5.0 quarts with engine oil filter change
The 4.0 liter V6 takes ( 5 quarts ) with engine oil filter change
According to the 1999 Ford Ranger Owner Guide : With engine oil filter change ( 4.5 quarts of engine oil ) for your 2.5 liter 4 cylinder
According to the 1999 Ford Ranger Owner Guide : The 5 speed manual transmission takes ( 2.8 U.S. quarts of Motorcraft MERCON automatic transmission fluid )
According to the 1999 Ford Ranger Owner Guide : With engine oil filter change : The 2.5 liter four cylinder engine and the 3.0 liter V6 engine take ( 4.5 U.S. quarts of 5W-30 ) The 4.0 liter V6 engine takes ( 5.0 U.S. quarts of 5W-30 )
For a 1999 Ford Ranger : With engine oil filter change : The 4.0 liter V6 engine takes ( 5 quarts ) The 3.0 liter V6 engine takes ( 4.5 quarts ) The 2.5 liter 4 cylinder engine takes ( 4.5 quarts ) According to the Owner Guide
The 2008 Ford Ranger owners manual shows ( 5 quarts ) of engine oil ( 5 W - 30 ) WITH FILTER CHANGE
A 4.0 ford ranger will hold 10 quarts of transmission oil. This is if the if the transmission is totally dry including the lines and the transfer case.
For a 1992 Ford Ranger , 2.9 V6 : With engine oil filter change : ( I believe that is 5.0 US. quarts )