2nd Gen Non-Engine/Transmission Take care of vacuum leaks ASAP

[mwilson]

I am going to take time to share these pictures with you all, it seems that there have been several threads this week regarding malfunctioning CAD units.

Some want to repair the system, some want to replace it with a cable actuator.



The point I want to make with these pictures is whatever you plan on doing, do it before the wear begins. If you don't, the cable kit won't help you as the sliding clutch will simply snap the fork off or bend it.



If your light starts to blink when in 4WD get at it immediately or risk damages of at least $300. 00 just in parts.



These pictures are of the '97 that I bought last Dec. , it was January before I got it on the road and noticed the CAD problem. I fixed about 10 vacuum leaks and it still did it. I figured out what was going on and hoped it would make it until spring.



Well, it didn't. It got bad enough to break the CAD housing and fork one cold January morning so I had to deal with it right then.



One new inner RH axle, new shift collar and new CAD unit later it is as good as new.



See how the teeth on the inner axle have lost the blunt end and worn to a point???



There is no way that collar will stay on that shaft under pressure.



Notice the side by side comparison of the new shaft vs. the old shaft.



Thought you might want to see these.



Mike.

 

[mwilson]

A few more shots... . see how the old collar is worn as well??



Mike.

 

[NIsaacs]

Good post Mike



I noticed in the picture the collar has an offset. Is it possible it might have been wrong from the factory or switched at some point during a previous repair? It is obvious that it was not engaging completely. Probably like you said, low vacuum/leaks. Does the new CAD come with the vacuum can? If not, is it possible it is also bad and not making it's complete cycle?



Nick

 

[mwilson]

It has been a year since the repair but I am pretty sure that I checked that out and the machined area of the collar had to be to the right. I wanted to make sure that this was going to be my only visit to that area of the powertrain... I remember mocking it up against the new shift unit and axles, etc. to make darn sure that was the way it went in there.



The new CAD actuator kit does not have the housing or fork with it. My housing was alright but I had to get the new fork from Mopar.



I think a big leak coupled with hard duty such as plowing snow makes this happen fast, my suspicion is that the collar will follow the outer axle when you turn the wheels short and the outer axle entends a bit.



All that holds the fork is vacuum, there are no springs or anything to help. The spring on the 4wd indicator light switch will overcome the fork if there is any leakage at all and that pushes the fork back enough to lose half of its engagement when in 4wd.



Mike.