i have a few problems and i am not sure where to look. first of all 4wd will lock in hard and it will kick in and out of 4h above about 45mph( light will start flashing and will kick out) also at take off i lose air from the vents. i assume these problems are both vaccuum related, but i am not sure where to look. also during idle the truck will idle up and down with the altenator guage fluctuating from about 12 to 16. altenator going bad? any help would be great. thanks fellas

 

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gmlogan:

I have a 96' Dodge CTD and have had similar problems with my shifter/transfer case with the shifter "kicking out of 4WD." The first and most simple thing to check is to see if the stock plastic insert is damaged where the linkage comes from the shifter and goes into the T-case arm. Mine was pretty worn out and would not let the shifter fully engage the T-case. If that plastic insert is NOT worn, check the adjustment on the shifter and linkage. They wear out and sometimes bend and that will also not let the T-case fully engage.

The problem with the air on your vents is vacuum related. Is your ABS/Brake light staying on in the dash?? Sometimes they will be on with a vacuum problem on the trucks. Also, check the vacuum lines that run along the firewall just under the cowl. Sometimes the hoses are loose on the ends and sometimes they are completely worn out. I have had to replace some of mine.

Hope this helps you some Sir!

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John_P

 

Also check the vacuum actuator at the axle.

 

i checked all vacuum lines. all appear to be good. put hand pump on actuator and 4wd locked in as it should. changed insert and readjusted linkage. no help, but i do have a new oil leak that appears to be coming from the vacuum pump. would this be causing both the 4wd and vent air problems? if so, is the vacuum pump rebuild kit any good?

 

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gmlogan:

Sounds like you are making progress Sir!

Yes, if your vacuum pump is somehow defective that could also be a problem.
I will be honest with you, I have not had good luck with the vacuum pump rebuild kits. I tried them and ended up having to buy a new vacuum pump. But, if $$$$ are an issue for you, try the rebuild kit first. They are cheaper.

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John_P

 

Put a gauge on the vacuum , at pump , to see if pump is working good , then go to the ends [ where the vacuum works , like ft axial & heater control ] , no sense in putting parts in till you know what the problem is .
I've looked at the kits , but have not done one yet .

http://www.fixinrams.com/

 

The alternator cycling thing is normal, mine has been doing it since the day I bought it.

 

If it comes to replacing the vacuum pump just buy a Ford diesel truck electric pump.
They last forever and only cost about $70.