Simple question. Why can the 81-84 models not "shift on the fly"? Thank you
The front disconnect axle has no way to sync speed between the rh axle and the front diff. You have to stop engage and slowly drive to engage coupling. It is possible to lock the front disconnect into position and redo the vacuum lines to make it shift on the fly. Eliminates a lot of the vacuum plumbing. http://amceaglesden.com/guide/Front_Axle_Lock
Ahh..now I understand. Thank you.