Bill

Driving around in the winter(especially in Canada) having shift-on-the-fly 4wd is really nice to have. I discovered recently upon driving back from hunting a while ago, that my recently installed R1FA behind my W56 is most defonitly not shift on the fly. This is backed up by marlincrawler.com.

I know(after having a 92 4Runner) that chain drive t-cases can be shifted while moving, but I'm pretty sure I can't swap one in withmy current tranny.

So does anyone know if its possible to give a gear driven case "shift on the fly"?

Yoda

If your hubs are locked, you can shift on the fly. (don't know about ADD though)

I can do it with my 71 landcruiser too. As long as the front axle is turning (hubs are locked) all that has to happen in the TC is the coupling slides into place, locking the front to the TC.

Definitely cannot shift to low range on the fly

toyota_mdt_tech

Well, the synchro transfer cases were used on all the ADD sytems and woudl allow you to shift on the fly. Also, earlier transfer cases like the ones with the early "auto hubs" wer ealso synchronized and would bolt up to your rig. But you must find one that did have the auto hubs. Auto hubs came on manual trannys only. These have the syncronized transfer case where it would engadge the prop shaft first, then the hubs deteted movement (power) and would lock up. But in reality, if you have manual hubs ands like shift on the fly,. turn both hubs to locked and then just shift ont he fly as needed anyway. But only between 2hi to 4 hi, never shift to lo unless you are stopped or almost stopped.

CJM

You can shift up to 50mph (I wouldnt do it) to 4 hi if your hubs are locked. But to 4 lo you gotta stop. I stop anyways for both just incase, dont wanna messup anything.

Bill

Ok, allow me to clarify: I don't have ADD on mine: came stock with manual hubs, and there is no ADD "box" on the passenger side axle tube.

I know the under 50 thing was valid with my 4Runner with ADD, but doesn't seem to be on this rig. I was driving on some back roads in 4hi, and when I hit the "clear" highway I went to shift back to 2hi, and I could feel it resisting. I could pop it out of 4hi to a "neutral" spot between 4hi and 2hi, but it wouldn't shift all the way to 2hi(I could feel/hear it grind, so I stopped to finish the shift).

toyota_mdt_tech

I'm familiar with the "ADD" system. You can still shift from 4hi to 2 hi and back to 4 hi as long as your hubs are locked wiht your system. Reason it was a little stiff was because its a "part time 4WD" and this means front and rear axles will rotate at different speeds. This can cause some binding (actual term for this is called tight corner braking) and all you need to do is "while applying some pressure pushing forward to 2Hi on your transfer lever, kinda snap the throttle (let up and get back on it quickly) and this will usually allow it to release enough pressure to get out of 4hi. You probably shifted back to 2hi while you were no longer on a slick surface. If you can do this just before you enter the dry surface, it will come out easier too.,