Hi, I have an auxiliary gas tank on my D90 that uses what I believe
to be a filler neck from ROW truck. Currently, it has a generic, non-locking fuel cap on it.. and I would like to replace with a locking cap if possible.
I would appreciate if someone would help by measuring the diameter of your filler neck hole for me. If the measurements are the same... then, I would happily order a OE locking cap. Thanks!
The filler cap is not the screw on type but similar to a radiator cap with has two notches.
Filler cap (under side):