[4priebe]

New here. Got hooked on my 73 Commando by a friend which was a jeep freak and now he has died and I still have question hope to get answers. I have a Dana 20 in my commando and have come up with a Dana 18 with a overdrive in it. Would it do me any good to swap them out!! Looking to drop rpm's at high speeds and of course better mpg!! Or any othere ideas! Please help !!!!!!

 

[Saddle Tramp]

The main difference between the 18 & the 20 is that the 18 has an offset rear drive while the 20 has a centered rear drive; this effects where the pumpkin sits on the axle, either off set to the passenger side or centered. In reality the late model 18 and the 20 cases are interchangeable but there is no way to add the overdrive to the 20. So as a 73 Commando has a centered rear end and if you install the 18 your dive line would not line up which could cause you problems.