Rebuild Vacuum Shift Motor / 4wd Actuator
#1
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.
#3
#5
#6
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
#7
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.
Last edited by AndyMan; 03-01-2010 at 09:40 AM.
#8
Diesel Bomber
iTrader: (1)
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
#9
#10