My new to me 2.5 liter 5 speed 1986 (edited,sorry, not an 85) Comanche X won"t go right into 4 wheel drive.

You are watching: Why wont my 4 wheel drive engage

 

The are no noises from the Transfer case, it does interact low variety, but does not drive the front wheels. A couple times I obtained a neutral in 4 low, but various other times it engages low yet does not drive the front axle. Tbelow is no indication in the dash as to if it is in 4 wheel drive. I assume the indicator would certainly be on the appropriate light cluster where the up transition light is. 

 

I have read a little bit around the vacuum lines having actually somepoint to carry out with engaging the front axle. I have actually searched this forum and else wbelow and also have not discovered an excellent overview on the topic. I have actually not determined if I have an NP 231 or NV 231 transfer situation, or what the difference is.


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Location: Connecticut
Posted November 23, 2014

My brand-new to me 2.5 liter 5 rate 1985 Comanche X won"t go into 4 wheel drive.

 

The are no noises from the Transfer instance, it does connect low variety, yet does not drive the front wheels. A couple times I acquired a neutral in 4 low, but other times it engages low yet does not drive the front axle. There is no indication in the dash as to if it is in 4 wheel drive. I assume the indicator would be on the ideal light cluster where the up transition light is. 

 

I have check out a bit about the vacuum lines having actually somepoint to do via engaging the front axle. I have searched this forum and also else wright here and have not discovered a great overview on the subject. I have actually not determined if I have an NP 231 or NV 231 transport instance, or what the difference is.


 

If you have the right to acquire to low selection, the carry case is functioning. And you"re wrong on where the 4WD light is -- it"s in the condition light cluster to the left of the primary gauges.

 

As already pointed out, your MJ has a vacuum-managed axle disaffix. If you don"t have actually excellent vacuum, it won"t engage. The 4WD light is also actuated by a vacuum switch, so that"s a 2nd hint that you have a vacuum leak. You might try to track it down (which would certainly be a great principle, since it more than likely also affects your cabin heating/ventilation distribution), or you can simply permanently lock the axle in the involved place.

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Edit to add I overlooked the reality that you shelp you have an "85. That"s amazing, because there is no such thing -- the MJ was introduced in the 1986 model year. What carry instance does your MJ have? Tright here must be a label on the driver"s side sun visor that will say either "Command-Trac" or "Selec-Trac." The operation of the 1986 Selec-Trac was exceptionally different from the MP242 Selec-Trac of later years. The "86 would not have an NP231. If it"s Commend-Trac it would be an NP207, IIRC. The 231 didn"t come in till 1987 or probably 1988.