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99 cummins 148kmiles bad vacuum pump?

978 Views 1 Reply 2 Participants Last post by  mthomp1
My 4x4 is not working all it does is grind when you try to use 4x4 and there is no vacuum going to the actuator at all and the 4x4 light doesn't come on also all my air comes out defrost and will not come out any other vents unless you put your hand underbthe dash and pull that lever down any help appricated
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Vacuum leak, most likely. Get a good look at all your vacuum lines. Start from the firewall and follow them to where they end, looking for cracks or ones that are disconnected.
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