AOA,
Dear Saad_q bahi,
The jeep also comes in 4-forward gearbox CJ5 original 4 speed gear box complete assembly is for 11k in Karachi. Another option is to put Dyna 5-speed gearbox coupled with original 4x4 special gear but this costs around 25-30k these days as Dyna gear prices have shot up.
Both the suggested options are tested and would fit with your 2C engine.
Waslaam,
M.HAMZA