Rebuild Vacuum Shift Motor / 4wd Actuator
 

After much troubleshooting, I've determined that the vacuum shift motor is not holding vacuum. Some people call this thing the 4wd actuator. It's the gold "bulb" with vacuum lines connected to and controls the shift fork on the Central Axle Disconnect. Apparently that shaft goes into the "bulb" and connects SOMEHOW to a diaphram.... It's pretty simple, and I can tell from looking at mine that someone has pried the thing open at least once and "repaired" it. Anybody ever torn into one of these rascals? I could just replace it... but I like to tinker. :)

once they wear out on me the are done. axle gets a tack on each side to hold collar.

That'll work! LOL... but I'd think it would eat tires... am I wrong? I run 35" M/T's, and they 'spensive. :)

no they dont. it works good but makes your front driveshaft run all the time though.

Interesting, thanks man. I'll consider that. I'm thinking of homebrewing a "posi-lock" though probably. I want to disassemble that "bulb" and figger out how to attach a pto cable to it. then put a spring on the shaft between the housing and the fork. that should fix it.

posi lok works great on these,I bought mine but if you have the time ,you could make one fairly easy,mine uses a hand throttle style cable that screws out and locks in place,sometimes you can,t just pull it out(with button pushed) because the shafts and collar are not lined up but when you put strain on it and move a little it goes right in ,try to leave your shift light sensor attached:tu:

Kewl. :) Yeah, that's the beauty of the vacuum shift setup... it puts a "gentle" pressure on the donut and then when the axles are aligned, it slips over the other axle and locks you in. You're doing the same thing by tugging on that cable until it locks in. I'd rather just have the vac system work, but it's too expensive to fix. I'd rather rig up a posi-lock.. That cable with the button that you're talking about is a PTO cable (probably very simmilar to this top red knobbed one:Vernier PTO Cable . They've adapted it to their system. I like the fact that they engineered their own cover, but I'm not sure why they did that. I think I'll try disassembling the motor and attaching my cable directly to the shaft. I'll put a spring on the shaft inside the housing to create an automatic return when I release the cable by the button. Seems to me to be a better design than theirs. Although, theirs is rock solid, so any "nagging" I do of it is just nit-picking. :c:

QK4904 Vacuum Shift Kit for 1994-2002 Dodge $169.96.I guess thats a little steep,Just in case you change your mind.Dodge Front Axle & Steering

Yep. Too steep. I just got a CAD gasket, shift pads, and the e-clips from Dan at Quad. Good people to deal with. I can get a chineese knock off actuator/motor for like $75, but I can still do a posi-lok cheaper than that, and never have to worry about failure again! :)

that is the same type of cable,the reason posi-lok made there own cover is to make the cable sheath screw in and adjustable in length,the reason I changed mine is to make sure I have 4 wheel drive when I need it :w2: