4X2X4?

Trebissky

Active Member
Joined
May 16, 2005
Location
Durham, NC
Anybody know what might make 4High NOT work while 4Low does? I've been trying mine out (S-15 Jimmy) and it seems like that's what's happening. I'll try to gently roll up to and over A CURB, and in 4Hi it won't but then, I don't hear or feel it going into 4WD either. When I put it in 4Lo it'll pull up over the curb with no prob, AND when I shift into 4Lo I hear and FEEL the transcase clunk into gear. :confused: I should mention that the 4WD Indicator panel (on the floor) doesn't light up at all any more, either.

Just for comparison I took my wife's Front Drive Camry and tried to go over the same curb the only problem I had was it scraped because it's so low slung, but it pulled up same as the Jimmy in 4Lo.

Any ideas gratefully accepted. Chase?
 
In 4-lo it will pull up easier naturally. The low range is also a different collar mechanism than the 4wd. Easiest way to know for sure is jack up the vehicle, or pull the shafts and watch the yokes for spinning.
 
Trebissky said:
I'll try to gently roll up to and over A CURB, and in 4Hi it won't
Click to expand...

Are the rears spinning and the fronts aren't?

It's quite possible for a chain-drive Tcase like a NP208 to not work in 4hi, but work fine in 4lo. The forks can wear, springs go soft, etc and cause all sorts of weird behavior.

But it doesn't sound like you've done enough troubleshooting. Could be nothing wrong, and you're just noticing the mechanical advantage of low range.
 
Not sure on you truck year but there used to be a vacuum control on the tcase that ingaged the front axle. since your indicator light does not come on I would look at that vacuum Switch for the possible problem. it might work in 4lo but not in 4hi
 
Are you sure it doesn't work in 4-hi? My '03 taco doesn't clunk into 4-hi either but I'm fully confident that it is actually in 4wd. It makes the same clunk into 4-lo that yours does.

My initial thought is that your "climb the curb" test isn't the best one. I'd find a dirt road, put it in 4-hi, and try to "burn rubber". If you spin in the front and back 4wd works. :)
 
saf-t scissors said:
Are the rears spinning and the fronts aren't?
Click to expand...
In 4HI the right rear will be the one trying to push forward, and so hard it digs a nice little trench in the gravel I'm on. But the fronts do nothing but sit there against the curb. I open the driver's door so I can see part of the tire and it's not even trying to turn. Once I go to 4LO the fronts pull along with the rears.

But it doesn't sound like you've done enough troubleshooting. Could be nothing wrong, and you're just noticing the mechanical advantage of low range.
Click to expand...
No, like I said I tried the same thing with a Camry and the front wheels pulled right up and over the same curb. There's a whole different feel to it. I get that feel with 4LO but not 4HI.

Not sure on you truck year (1990) but there used to be a vacuum control on the tcase that ingaged the front axle. since your indicator light does not come on I would look at that vacuum Switch for the possible problem. it might work in 4lo but not in 4hi
Click to expand...
That may be it. Also, the vacuum hose that runs to what must be that switch (small black cylinder right near the radiator?) from the (carburetor?) under the air filter had slipped off at both ends. The end near the cylinder had a lot of oil all over it from a leak elsewhere, I cleaned it off and hope it'll stay put now.

Question: assuming that cylinder IS the switch you're talking about, how much would it cost to fix? And what do I need to get that indicator working again?
 
That may be it. Also, the vacuum hose that runs to what must be that switch (small black cylinder right near the radiator?) from the (carburetor?) under the air filter had slipped off at both ends. The end near the cylinder had a lot of oil all over it from a leak elsewhere, I cleaned it off and hope it'll stay put now.
Click to expand...

The vaccum engagement should have a line running from the t-case to the front axle vacuum connect, a big boxy looking thing in the middle of the axle tube.

If the vac-disconnect is broke you can do like Chris said with the posi-lock. Or you can purchase a 1-piece axle to put in that side. Won't allow 2-lo but will be stronger than a 2-piece axle.
 
To accurately tell if you 4wd is working simply engage the 4wd with the vehicle in gear allow it to move forward an couple wheel revolutions to ensure engagement then turn the truck off and set parking brake then jack up the passenger side front wheel. If you can turn the wheel by hand then 4wd isn't working, if the wheel won't turn then you are in 4wd. I also have a s series jimmy and the vaccum system is prone to failure but if it fails you won't have 4wd at all because the front axle won't engage. If the vaccum actuator is the problem they can be bought for around 60 bucks on ebay.
 
i dont understand what you mean by an entire different feel to it. My Jeep feels the same in 4H as it does in 2wd...I only notice a difference if I do a tight turn, thats when i can feel the front tires pulling as well.
 
ok seriously if its not your vacume 20 bucks says its your linkage cause you have that 3"body lift it porbably wont let you shit all the way into 4hi. I had the same prob with my Z71 for a while but with 4 lo lo would engage but no 4, well i got under there and my linkage is threaded so has adjustment built in so i just adjusted it waaaay out and bingo. Give that a try cause those body lifts almost always require linkage adjusting.
 
Thanks for all the tips. Here's the thing... I went out to DPG Saturday for the "Meet & Greet" and had it in 4LO all day, then somehow cut my radiator hose. I got it Ducktaped up and kept running for a while, until a guy got me a new hose to swap out. As soon as I did that, the 4WD quit again. I had popped the vac hose off the (carburetor/fuel injector?) and put it back on again, but it still didn't work. I found this out for sure when I tried going through a mudhole I'd already been through twice, and it wouldn't climb back out now. :(

So how can it be working one minute and not the next? :confused:

Anyhow, I probably will get one of those Posi-locks whenever I can get the $ together, meanwhile I'm still trying to figure out what's going on with it. I'll check on that linkage adjustment and all, too.

Meanwhile... I think I know HOW that radiator hose got cut, too. After I washed off half of DPG I noticed that the two body lift disks that are supposed to be at the front of the frame... aren't. Nothing there at all. So I figure I went over a rock high enough to make the frame flex, but the body didn't flex with it and ZIIIPPPP, the alternator caught it good.

So how much do JUST TWO sets of 3" lift disks, mounting bolts and whatever else is needed cost and does anybody have some?
 
Back
Top