2005 Toyota 4Runner Owners Manual - Page 318

'05 4Runner_U (L/O 0409) TRAILER BALL Follow these easy steps to properly determine the correct trailer ball for your application: 1. Determine the correct trailer ball size for the trailer coupler. Most couplers are stamped with the required trailer ball size. The sizes you will most likely find stamped on the coupler are: Trailer class IV 1 2 3 4 Trailer ball load rating Ball diameter Shank length Shank diameter Typical trailer ball size 2 5/16 in. 2 in. 1 7/8 in. II and III I 2. Select the appropriate trailer ball to match or exceed the gross trailer weight rating of the trailer. The trailer ball load rating should be printed on the top of the ball. 3. When mounted in the ball mount, the threaded ball shank must protrude beyond the bottom of the lock washer and nut at least 2 threads. The trailer ball shank must be matched to the ball mount hole diameter size. NOTICE Only use a ball mount attachment specified for the Toyota 4runner. 1 Coupler 2 Trailer ball 3 Ball mount attachment 318 2005 4RUNNER from Sep. '04 Prod. (OM35843U)