I have a 94 U42T with the dual speed push button 4wd. The other day I shifted into the 4wd and it "clunked" into position. Didn't think it was anything big, but now I cannot disengage the 4wd. The vacuum lines are all conenctedd (not tested), I can hear the solenoids click when hitting the push button for engaging/disengaging...Just looking for some guidance before I really tear into it and put it out of service for an extended time (it's used daily). I can drive it as is, but it's always in 4wd...but will I do more damage. When letting off the gas you can feel the transmission slowing down that the 4wd drive unit may be bound and I'm not a great mechanic. Any help is appreciated:frustration:!!
I have the same issue. You can manually disengage the 4 wheel drive, but it gets to be a pain in the rear if you have to do it often. Since you know where the vaccuum lines are, it should be self explanatory on how to do it.
Are you shifting on the fly? As far as I know you need to be stopped dead to shift into or out of 4wd...I may be wrong on this but I have been doing it just in case...have you tried backing up?
That's the first thing I tried fupabox. I have been in the past to shift on the fly with the 4wd in the past you just have to back off the throttle to get it to engage. This go around it made a pop sound as it engaged like grinding your gears into position Norskemann82 do you know exactly what is wrong with yours, or just a work around solution?
Not sure about the newer trucks but certainly stop before shifting into 4x4 on the older models. If your truck is a older model and has the external actuator on the front diff. you can watch it move in and out when shifting into 4x4. The late 90's truck went to everything inside the diff. and you cant see them work.
This morning, before going to work, I reversed the vacuum lines and that disengaged it okay. Tonight, I will start replacing vaccum lines and work my way back to see if there is any contaminates in the lines. I can hear the air in the one but not the other...any additional pointers? I'm just glad it's not the front diff...
I'm almost positive it's one of the vaccum switches now. I'll order one tomorrow and confirm when it's here.
FInally FIxed and working great again It was the vacuum switch that is located at the back of the transmission. Original Mitsubishi part brand new was $128 from G&R Imports. Problem Resolved.
Me and a buddy are working on 3 of these trucks either stuck in or stuck out of 4x4.Easy fix is to take vacuum lines off vacuum switch solenoid,spray with WD40 into lines and vacuum solenoid,top and bottom one.Take the linkage apart and use awire wheel on a drill and clean linkage.Then lubracate with anti-sease. Put back together and will work like knew.
I have a 1990 Sambar that doesn't seem to come out of 4x4 . This vacuum solenoid problem might be my situation as well ! Great info . What the heck is a free-axel solenoid ,what is it's function ,and where would it be located .Any help would be super !
Cleaning the solenoids is what I did as well. Realize also that the "dust cap" on the end of the solenoid is there to allow air to equilize. I proved that with a vacuum hose cap, wouldn't do anything until I took my cap off again. I swapped the lines to opposing solenoids to verify operation. One worked the other didn't. After cleaning, they both work. Does allow shifting on the fly into-out of 4x4, but I wouldn't try low range unless stopped. Bill Deadwood, SD
4x4 actuator solenoids Thanks to N7MOG for the great info. I'll be getting some Sambar dirt under my fingernails in the next few days ! Regards .
Hoping this thread is still active, I have a 1991 Sambar and I can't get the 4wd to disengage using the button on the gear shifter, how do you disengage it manually? Appreciate any help. Okay, and another question, is the Sambar rear wheel drive and then when you engage the 4wd it engages the front wheels? I see a drive shaft from the rear to the front, should that turn freely if the 4wd is disengaged? Okay will wait to see what everyone says.
Thought I'd post here instead of making a new thread. My 95 u42t started being very reluctant to engage 4wd. I've always shifted on the fly with no noises or other issues as it would not engage unless the wheels were turning. Anyways, the last 3 times I've engaged it, it took forever to engage, like 100yards or so and went in with a grind. Slow speed(under 15kmh) with wheels straight as to avoid any clash of front/rear wheel speed, but still grinds. I'm gonna check vaccuum for the slow engagement, just the grinding is scaring me a little. Anyone else encounter this and have any luck finding the cause?
IMHO, if shifting on the fly I would be at a snails pace. As for taking its time to connect I would look first at vacuums lines. If the truck has never had the lines replaced start replacing them. Its typical to see weather cracking where they slip over the hard nipples and where they make 90 degree turns. You can often look at them and they look good but bend them and you can see a crack.
Those who have cleaned your solenoids am I doing something wrong ? Clean and still won’t engage 4WD (will disengage with button , after I’ve manually engaged 4WD) some of you have noted you swapped vacuum lines to confirm one solenoid was bad. I swapped vacuum line and it still won’t engage 4WD.