I have a 1998 Pajero (Montero) I have only just got it and the 4x4 light stays on, the selector seems to go in and out ok but I have pulled the engine to do some repairs but neglected to see if it was actually stuck in 4x4 or could it just be the switch, is this a common thing? Is there a way of testing before I put the engine back in
Stuck in 4x4
- Thread starter Kevvy
- Start date
nwoods
Expedition Leader
There are two basic kind of issues. 1) the actuator is sludged into place, resulting from seldom being used. Working it in and out of 4wd a number times helps free up the lubricant again and it will start to work properly.
2) the shifter has a "ball" of hard plastic that engages the tines (or forks) in the transfer case. This ball is made from red plastic and distentegrates over time. The original (1991-1997) shifter used a white plastic that lasts forever. Look up "shifter ball replacement" or "White shifter ball" and you'll find threads on this. This is more involved to fix, but still easy to do yourself if you can find a replacement.
2) the shifter has a "ball" of hard plastic that engages the tines (or forks) in the transfer case. This ball is made from red plastic and distentegrates over time. The original (1991-1997) shifter used a white plastic that lasts forever. Look up "shifter ball replacement" or "White shifter ball" and you'll find threads on this. This is more involved to fix, but still easy to do yourself if you can find a replacement.
Thanks for that, so it is most likely not the sensor, it seems to shift fairly easily I put it into high 4 and it showed orang lights but when I shifted into low 4 all the lights went out.
I assume changing out the ball can just be done from the top, I dont need to take out the gearbox
Yes that's correct, sorry for being a bit vague, since I have started to dismantle the vehicle there is no battery and so asking questions from memory
CharlieNorth
Well-known member
Did you drive the vehicle after shifting out of 4wd? Or just shift it and note that the light was on?
The light was on when I got it I drove it and tried shifting through all gears but only around the block, it was not registered so am doing a rebuild
I’m not 100% sure, but I think what you are seeing with those green L and R lights is only an indication of the front diff clutch being engaged or not. They are not necessarily indicators of anything happening in the 4x4 transfer case (“transmission”).
When you shift the 4x4 lever into the Active Track mode (or the “lowest level” of 4x4 function, basically a crude all wheel drive), this sends a signal to the pneumatic system to engage the front diff clutch, and those lights turn green. They then stay green through all the other 4x4 modes. To my knowledge the only time an indicator on that display should have any relation to what’s going on in the transfer case is when you lock the center diff (it will turn orange then).
Real life example: I’ve recently had a behavior starting when I am NOT in 4x4, where if I’m climbing a big hill and using a lot of throttle, those green lights will flicker on me, and if the road is smooth, I can actually feel a slight drag turning on and off, similar to what a/c does but not as much, as that front diff is barely engaging on and off. Even though I’m not in 4x4, if the front diff clutch is engaging it is forcing the driveshaft and some gears inside the transfer case to turn, and that adds drag you can feel. Why is this happening? I believe my pneumatic controllers are slowly failing (leaking) and when under long duration high vacuum during heavy throttle, vacuum is getting past the valve and engaging the front diff clutch even though I’m not in 4x4. I think the system is designed so that if the pneumatics fail, the default condition is to engage the front diff clutch so that if you ever did need 4x4, it would still work even with failed clutch pneumatics. When you are not in 4x4, the vacuum system is actually constantly holding back the clutch actuator. If it fails somehow, the system will engage whether you want it to or not. Can anyone confirm this?
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So for Kevvy, I think the short version is that if those lights are on constantly, it’s either a failed sensor, OR your pneumatic system controlling the front diff clutch has failed and your spinning your front diff and propellor shaft all the time. I think one way to diagnose this would be to put truck in neutral and push it, and have someone eyeball the front driveshaft. If it turns and you aren’t in a 4x4 mode, your clutch is engaged when it should not be. Only thing this hurts is gas mileage! Of course you’d want to do this with an engine running since that’s the source of the pneumatic vacuum.
When you shift the 4x4 lever into the Active Track mode (or the “lowest level” of 4x4 function, basically a crude all wheel drive), this sends a signal to the pneumatic system to engage the front diff clutch, and those lights turn green. They then stay green through all the other 4x4 modes. To my knowledge the only time an indicator on that display should have any relation to what’s going on in the transfer case is when you lock the center diff (it will turn orange then).
Real life example: I’ve recently had a behavior starting when I am NOT in 4x4, where if I’m climbing a big hill and using a lot of throttle, those green lights will flicker on me, and if the road is smooth, I can actually feel a slight drag turning on and off, similar to what a/c does but not as much, as that front diff is barely engaging on and off. Even though I’m not in 4x4, if the front diff clutch is engaging it is forcing the driveshaft and some gears inside the transfer case to turn, and that adds drag you can feel. Why is this happening? I believe my pneumatic controllers are slowly failing (leaking) and when under long duration high vacuum during heavy throttle, vacuum is getting past the valve and engaging the front diff clutch even though I’m not in 4x4. I think the system is designed so that if the pneumatics fail, the default condition is to engage the front diff clutch so that if you ever did need 4x4, it would still work even with failed clutch pneumatics. When you are not in 4x4, the vacuum system is actually constantly holding back the clutch actuator. If it fails somehow, the system will engage whether you want it to or not. Can anyone confirm this?
.
.
So for Kevvy, I think the short version is that if those lights are on constantly, it’s either a failed sensor, OR your pneumatic system controlling the front diff clutch has failed and your spinning your front diff and propellor shaft all the time. I think one way to diagnose this would be to put truck in neutral and push it, and have someone eyeball the front driveshaft. If it turns and you aren’t in a 4x4 mode, your clutch is engaged when it should not be. Only thing this hurts is gas mileage! Of course you’d want to do this with an engine running since that’s the source of the pneumatic vacuum.
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plh
Explorer
Hoses are on the front differential - LH tube
plh
Explorer
Correct. When the vehicle is off (or no vacuum for any other reason) the front differential jackshaft clutch is in the engaged position.