I feel like a dumbass asking this question but wheres the cap to fill up the trans fluid for a 4.3L tbi 88 with 4x4 trans .

Pull out the dipstick and insert a funnel. Fluid is added here. Do not overfill. Stop and check after you add a little. By the way the 4X4 transmission is the same as 2wd. Your 4X4 has a transfer case for 4 wheel drive.

Yeh its red and on the passenger side of the motor