Effects of vacuum on 4wd.
- Thread starter scrubber3
- Start date
off-roader
Expedition Leader
Yup use 4H when driving through the desert. We have lots of that in the southwest.
Nothing funner than blasting through the desert at speed... well, except maybe stopping in time before you hit something. LOL
Monterorider
Adventurer
So you had grinding noise before you replaced (because of stretched chain?) t-case and now after some wheeling with new t-case? No noises in the interim? Is you floor shifter ok (shifter rail in t-case?). You've got to be able to move in with center diff locked.
Monterorider
Adventurer
With center diff properly locked in 4Hlc or 4Llc power will go to rear wheels and truck is going to move not matter what's going on up front. Sounds like it' snot moving at all. Right? Then it has to be t-case.
scrubber3
Not really here
That's why I replaced the tcase to begin with.
The noise started just as I was starting the trails. I decided to keep it out of 4wd the remainder of my trip..... I find it hard to believe that I have been involved with 2 bad t cases in a row giving the history of these. At least , I certainly hope not. Since I am having the exact same issue as the last one at that. I can also deduce that if this is the case then it would be a common thing to happen. (2 in a row?) I have better chances of winning the lottery.
The noise started just as I was starting the trails. I decided to keep it out of 4wd the remainder of my trip..... I find it hard to believe that I have been involved with 2 bad t cases in a row giving the history of these. At least , I certainly hope not. Since I am having the exact same issue as the last one at that. I can also deduce that if this is the case then it would be a common thing to happen. (2 in a row?) I have better chances of winning the lottery.
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scrubber3
Not really here
As it turns out, if you disconnect the vacuum from the front diff diaphragm, the differential will disengage. So let it be known that the 2nd generation montero does not have a fail proof system. Unless mine is just jacked up.
Now it makes a little more sense.... The way I see it is that I was losing negative pressure to the engagement slide therefore lessening the grip of the slide to the diff itself. I will open the differential this week to see the theoretical damage.
Now may be a good time to fab up a solid front axle for this thing.. I'll compare the cost to the benefit and go from there.
Sent from my iPad
Now it makes a little more sense.... The way I see it is that I was losing negative pressure to the engagement slide therefore lessening the grip of the slide to the diff itself. I will open the differential this week to see the theoretical damage.
Now may be a good time to fab up a solid front axle for this thing.
. I'll compare the cost to the benefit and go from there. Sent from my iPad
Now may be a good time to fab up a solid front axle for this thing.
unk03:Shucks. I liked the idea of the fail safe. Perhaps just finding another diaphragm? I'll be making a trip to that local junk yard soon and will probably snatch the two there.
Monterorider
Adventurer
Interesting. Did it in fact disengage taking vacuum off or was never engaged in a first place?
scrubber3
Not really here
Seems as though there isn't enough negative pressure to pull the slide into place. With the line attached to the diaphragm, it will somewhat work. Though very loose and pops out. When I just take both of the vacuum lines off, the front will not even attempt to engage. The test consisted of placing the tcase in the 4hi position and disconnecting the lines. The truck won't move and makes a whiring noise. When I connect the lines, the truck will move but not much. I think something is amiss in the area where the slide engages the differential.
Pending what I find tomorrow the fix will entail repairing any vacuum leaks/ diaphragm. And either replacing the slide or differential, or both. I also found that all 3 of the differential mounts are busted.
Sent from my iPad
Pending what I find tomorrow the fix will entail repairing any vacuum leaks/ diaphragm. And either replacing the slide or differential, or both. I also found that all 3 of the differential mounts are busted.
Sent from my iPad
Monterorider
Adventurer
Duh. Just realized there is no spring so. Diaphragm move rod one way or another vi vacuum so that even if your later release vacuum if you could say so, it still stays at whatever position it was before. So if you were in 4WD it will stay engaged and visa verse. hence if it never engaged or didn't have enough force to do so because of vacuum leak it could grind not in the diff itself but in disconnect between output shaft #1 hub #2 and connecting gear (#10) on driver's side.
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I'm very interested in this... in case I ever need to do this in the field.