Engine/Transmission (1994 - 1998) 4X4 quit working

[Coalsmoke]

The other night I went to use 4x4 (it worked fine a few minutes before) and no light came on and no 4x4 engaged. So, I do some reading and figure that it is probably the little vacuum operated thingy that sits on top of the front axel. I also found a post saying that someone was only charged $35 for a new one. So I went to the dealer today and he told me $350 CAD for a new one! Anybody else been charged this much? Any ideas? Anyone have one sitting in their basement. For 350 I could by two new manual locking hubs. Sheesh!

 

[Joe G.]

Before spending any money do some trouble shooting and find out what is wrong. There should be vacuum at the servo motor on the front axle. Apply some vacuum to it and see if it works. Check to make sure all the vacuum lines from the t-case to the front axle are connected like they should be. Especially in the block on top of the t-case. Check to make sure that the vacuum is switched like it should be when the t-case shift lever is moved. If you don't have a service manual this is a good excuse to get one. Most probably something has come undone somewhere and just needs to be put back on.

 

[Coalsmoke]

No, I have propper vacuum going to the actuator device, and it reverses when I go in/out of 4x4. However, the 4x4 doesn't engage.

 

[edmeyers]

hope this helps

Mine did the same thing i replaced the 4 port switch on top of the t-case it just unscrews and it still did not work although it was in bad shape kinda of sticking.



i was getting vacumn at the front axle but the light would not come on and axle was not engauged



i replaced the 2 vacumn lines from the axle to the steel lines and the t-case to the steel lines i would have perfered to go from the t-case strait to the axle but i only bought 10 feet of fuel line so i had to use the existing steel lines

it now works .



i concluded that the old lines were so old and oil soaked from leaking vacumn pump seal that when vacumn was applied it was sucking the line closed



hope this helps i would suggest Fuel line since it has reinforcing so this problem will never arise again.

 

[Joe G.]

Have you pulled the vacuum servo motor and tested it on your work bench to see if it works?

 

[Coalsmoke]

servo motor? is that the actuator that sits on the axle, or is it something different?

 

[Joe G.]

That's what the service manual calls that thing. If it doesn't work with vacuum applied out of the axle then you need a new one. If it does work then something is wrong with the shift mechanism; shift fork, e-clips jumped out of grove, or ?? There is a two page block diagram in the service manual about trouble shooting this stuff.

 

[Coalsmoke]

Well, I know that everything up to that point is working. What I'll do then is pull it of and do he vacuum test like you suggested. Do you think I would have enough lung pressure to move the hing myself?

 

[TJMoor]

I had a problem on Friday with mine... Pulling a 4 place snowmobile trailer

tried to turn around in the yard and she would not go into 4 by... It was cold around -10 degrees F. . and on Sat Am ,,, it went right in to 4 by... I found some moisture in the Vacuum lines from t-case to front axle ,,, blew them out with dry compressed air and we will see how she does today... .

Also you may want to check with a Dana Spicer Dealer on the Actuator, in Anch ,, Young's gear ,, is way cheaper then Anch Chrysler... .

Good Luck

Terry

 

[Joe G.]

I don't have any idea if you have enuff lung power or not. You might try hooking it to the front axle vacuum lines with it supported by an overturned bucket or something like that and shift it to see what happens. I like to test things in isolation from the rest of the stuff so I know for sure that it's a good test. If you have a piece of vacuum hose you could replace the small line on the hose from the vacuum pump with it and use that to test with.



I've bought so many parts that I just knew had to be the problem and were not that I always test as much as I can to make sure that my guess was right.

 

[dlmartin]

I am on my third vacuum motor and probably need to replace my second inner axle due to burred splines on the end! The shaft on the acctuator was bent the last time and caused the connecting collar to be partially engaged. I tried the Pos-Lok system too, and the shaft on the end of the cable bent like the vacuum unit. I've checked all bearings, end play, side play, etc. and nothing stands out!This is definitely a problem area on my 97 3500 which is used as a farm truck where 4wd is used often. Does anybody have any recommendations for permanent fix, or aftermarket source for parts from Dana or whoever?