Jump to content

Recommended Posts

Ok guys I honestly hate to start another thread but I have a serious problem. It is the dead of winter and my 4x4 won’t work! The engagement stick moves into place but no dash light or 4 wheel drive! I need to get this fixed ASAP! I used it last week so it worked fine then. Help?

Share this post


Link to post
Share on other sites
13 minutes ago, CTcummins24V said:

There are plastic vacuum lines running by the cowl. Start tracing them. There is a rubber 90 on the driver's side cowl that goes down to the vacuum pump that is known to dry rot.

I’ll do that. Seems weird it would all the sudden conk like that. I did notice that sometimes when I put it in the light wouldn’t come on until I released the clutch and started forward.... maybe that was a sign that it was goin out?

Share this post


Link to post
Share on other sites

If you have been doing in work on the top  and drivers side of the motor it is easy to knock the main line out of the 90 on the cowl. Just had this happen while putting a new starter in this past week. Happens to me a lot while working in this area.

Share this post


Link to post
Share on other sites
27 minutes ago, Me78569 said:

easy way to know if you have a vaccuum leak is if the vents switch or not.  If you have a vaccuum leak it will be on defrost no matter what

I had it on feet and face this morning and I think it was working fine. I’ll check after work.

31 minutes ago, dripley said:

If you have been doing in work on the top  and drivers side of the motor it is easy to knock the main line out of the 90 on the cowl. Just had this happen while putting a new starter in this past week. Happens to me a lot while working in this area.

I was working in that location last night. I’ll have a look after work.

Share this post


Link to post
Share on other sites

A hand operated vacuum test pump is a good investment, is not that expensive, and will allow you to accurately diagnose vacuum related problems. 

 

For example, the CAD unit can easily be tested.  Place the transmission into a gear and select 4-high or 4-low with the transfer case.  Jack up the right front wheel and disconnect the vacuum lines at the CAD unit on the axle.  Connect the vacuum pump to one port of the CAD unit; leave the other port vented to atmosphere.   Operate the vacuum pump and hand rotate the right wheel to ensure engagement or release of the CAD.  Swap connections and test again.  Assuming that vacuum held on each test, one test should allow the wheel to rotate freely, the other test should lock the wheel in place which means that the CAD is mechanically doing its job.  Using the vacuum pump you can continue with testing of all vacuum lines until you find the source of the problem.

 

If both tests pass and the 4WD light does not come on, then you have a bulb failure, an electrical wiring problem, or a CAD switch contact failure.

 

If the right wheel spins freely during both tests, then you have a CAD failure.

 

Vacuum leaks on these trucks are commonly overlooked until something fails.  The vacuum pump is very powerful and vacuum leaks can go undetected until they become large.  Remember, all air from these leaks pass through the vacuum pump, into the engine crankcase, and then out the breather vent.  You do not need this additional air flow out the breather vent!  This issue alone is reason to invest in a hand operated vacuum test pump.

 

- John

Edited by Tractorman
content
  • Haha 1

Share this post


Link to post
Share on other sites
3 hours ago, Marcus2000monster said:

I had it on feet and face this morning and I think it was working fine. I’ll check after work

If it was blowing on your face and feet you do have vacuum to part of the system. If you loose it completely it will blow out of the defrost only as was mentioned earlier. Mine will blow a little out of the floor also. Mine has always done that with or without the vacuum connected.

 When you say face is that from the defrost or the dash vents. I know defrost blows in my face.

Edited by dripley

Share this post


Link to post
Share on other sites
58 minutes ago, dripley said:

If it was blowing on your face and feet you do have vacuum to part of the system. If you loose it completely it will blow out of the defrost only as was mentioned earlier. Mine will blow a little out of the floor also. Mine has always done that with or without the vacuum connected.

 When you say face is that from the defrost or the dash vents. I know defrost blows in my face.

Dash vents

Share this post


Link to post
Share on other sites
10 hours ago, dripley said:

If you have been doing in work on the top  and drivers side of the motor it is easy to knock the main line out of the 90 on the cowl. Just had this happen while putting a new starter in this past week. Happens to me a lot while working in this area.

I’m not seeing where your talking about. Can you give a specific location? Thanks!

19 minutes ago, Marcus2000monster said:

I’m not seeing where your talking about. Can you give a specific location? Thanks!

Found them! So far I’m not seeing any disconnected lines but we’re working on it!

Share this post


Link to post
Share on other sites

If you look at the vacuum pump and just follow the 1/4" line it will lead you right to it. It is a little over half way from the drivers side to the engine just below the wiring bundles.

But since you have air blowing out of the dash vents, it is not likely disconnected as someone mentioned earlier it will default to the defrost if that line is disconnected.

  • Like 1

Share this post


Link to post
Share on other sites

Have you checked by cad if you got vacuum, and you can put a hose on actuator and suck vacuum on each fitting and it will engage and disengage. If all checks out there, then there is something by the transfer case that I never messed with myself but I know it's there. I wanted to eliminate as much as I could with all that vacuum stuff that's why I went with a cable instead, plus having a 2low is nice for backing up hill with a trailer, which can be done other ways. I just wanted to try posilock, and my actuator was on the way out so I was almost half way on the cost just replacing it. 

Share this post


Link to post
Share on other sites
1 hour ago, Dieselfuture said:

Have you checked by cad if you got vacuum, and you can put a hose on actuator and suck vacuum on each fitting and it will engage and disengage. If all checks out there, then there is something by the transfer case that I never messed with myself but I know it's there. I wanted to eliminate as much as I could with all that vacuum stuff that's why I went with a cable instead, plus having a 2low is nice for backing up hill with a trailer, which can be done other ways. I just wanted to try posilock, and my actuator was on the way out so I was almost half way on the cost just replacing it. 

I’m in the middle of doing so. Going to bed shortly I will continue tomorrow! Sure hope I can fix cuase it’s dumping snow right now! :thumb1:

Share this post


Link to post
Share on other sites
On 12/29/2017 at 8:32 PM, Dieselfuture said:

Have you checked by cad if you got vacuum, and you can put a hose on actuator and suck vacuum on each fitting and it will engage and disengage. If all checks out there, then there is something by the transfer case that I never messed with myself but I know it's there. I wanted to eliminate as much as I could with all that vacuum stuff that's why I went with a cable instead, plus having a 2low is nice for backing up hill with a trailer, which can be done other ways. I just wanted to try posilock, and my actuator was on the way out so I was almost half way on the cost just replacing it. 

I have not tested this yet I need to do so. I ended up going to town yesterday so didn’t get everything done I wanted to. Maybe this afternoon I can try this. 

Share this post


Link to post
Share on other sites

Like on mt 1996 Dodge Ram 1500 the vacuum motor got struck by something and tweaked the shaft causing it to hang up and stick randomly. Full replacement of the vacuum motor isn't hard but it would sure take care of any vacuum issues.

Share this post


Link to post
Share on other sites
11 minutes ago, Mopar1973Man said:

Like on mt 1996 Dodge Ram 1500 the vacuum motor got struck by something and tweaked the shaft causing it to hang up and stick randomly. Full replacement of the vacuum motor isn't hard but it would sure take care of any vacuum issues.

I am willing to do that if the motor is bad but I don’t want to throw parts at her. I also need to finish checking for vacuum at the switch on the transfer case. 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×