So if I'm in 2H my transfer case is not turning from the front axle. I don't have the axle delete but thought the drivers side axle would still turn the front shaft and transfer case. And if ya'll have shifted at those speeds, I definitely believe you!!

 

the front drive shaft is always spinning or coasting per say, most likely, but with the differential and disconnected center shaft its not spinning under power. In theory at 300mph, shaft spinning you could grab it and it will stop dead without force. Obviously inertia rotational mass speed ect makes this impossible but it could be done without damaging or stopping anything other then the shaft. You could put a stick through the ujoint to stop it from turning and drive indefinitely this way. Its just oil drag making it turn and its most like turning less speed then you're traveling.

 

Yep. With the CAD, and t-case in 2wd, the shaft is still spinning, but, it isn't powered..... Drivers side axle does not disconnect, so it is spinning the spider gears/front diff to some degree. With the CAD delete, or simply having it locked, the front shaft will be turning the same speed as the rear, even in 2wd.

 

I like this reasoning and it may be true. On some of these cases the synchros die and I don't know exactly what causes it, although I doubt they're all due to high speed (whatever that means) shifting.

Still, this is the best argument I've heard yet for a "speed limit"

 

Ok. Ya'll gave me a better understanding of how all of this works. I appreciate that. And HeyYou, I tested your method of getting it out of 4L. Came right out. Thanks. You would think after 24 years I would have figured that out. But I'm still a little pissed about having to pull the front differential to change out the driver side axle seal.
All right let me run this by y'all. The last time the tranny was rebuilt, they hooked up the vacuum lines backwards. So when it was in 4 wheel drive' no dash indicator light plus when in 2 wheel drive the 4W indicator was on. Simple fix by swapping the vacuum lines. It worked for a couple of years just fine. Now I have no indicator light at all. Any suggestions where to start? vacuum lines or maybe the bulb itself. Thanks for any input as always.

 

Yeah, why Dana decided to put the seal in the LEAST accessible location is a mystery to me..... I remember the good ol' days, when they were at the outer end of the axle tubes....

Verify you are getting vacuum TO the CAD. If not, start tracing it back to find out where you lose it. Also check up behind the engine, the plastic lines are exposed to a fair bit of heat, and the plastic gets brittle, and breaks....

 

Maybe I'm mistaken but having the lines reversed would reverse operation? 2wd in 4wd and 4wd in 2wd in terms of the CAD actuator? I would expect the sensor at first. Or even verify the actuator is moving and full stroke. I believe you can test the circuit by simply unplugging the connector and installing a jump pin. This would test the wiring and dash lamp.

 

The sensor is just a switch that is activated by the plunger on the cad..... If the light is coming on with the t-case in 2wd, Then the lines are indeed crossed somewhere, and putting the t-case in 4x4 accomplishes nothing.

 

Well yeah 👍

 

Thanks again! I got to check the vacuum lines from the CAD. The two from the CAD go to the transfer case. Then I found there are four lines that enter or exit here. No smoke from anything between the CAD and transfer case. There were two lines that are in the protective plastic that looked like they did go up to the engine compartment. One of those I think is one that provides the vacuum for the system and one that appears to be a vent terminating near the distributor. Not sure if I'm correct on the routing though. The transfer case definitely locks into 4L and 4H. So I am guessing the vacuum part is good. Hopefully tomorrow I'll have some help and will try dodgetruck2 method of testing the circuit by unplugging and jumping the pins. Does the transfer case need to be in 4L or 4H to do this check? And if I do get a dash light, can I assume it's the sensor? As always thank you for all input.