vac line to t-case?? *New info added!

[hippymill]

my t-case won't engage after my motor swap. I think that i have the vac lines connected wrong. there are 2 plastic lines (green and yellow) going to the t-case from the firewall, and 1 red line into the firewall(presumeably for the switch. This line is connected to the vac lines that connect the 2 ball shaped vac canisters. there is a vac line from the canister lines to the small connector on the pcv valve. is this right, or do i need to connect this line directly to manifold vacuum?

[ January 13, 2004, 05:17 PM: Message edited by: hippymill ]

[hippymill]

up

[grand_wag_85]

There should be a hose that goes into a black "soup can" looking thing on the driver's side also. Do you have a black rubber hose that comes out of the top of your tc? If so where does it go?

[hippymill]

haven't had a chance to check yet. i thought that the only lines to the tc were the yellow one and the green one that connect to the metal tubes and run to the tc. my rig has a ball type vac cannistr on the firewall, and one on the drivers fender. these are connected together on the same vac line.

[Ernzo]

There are some very good diagrams on this site that detail the lines.The ball canisters are vacuum reservoirs, they hold vacuum so that when you engage, there is vacuum available regardless of the engine condition. The one of the firewall is for the cruise control, as I recall.

In 4, the vacuum pulls the mode lever towards the front of the jeep. In 2, the vacuum pulls the lever back towards the rear. The range lever ought to be lined up straight up and down in 2, and lined up with the mode.

The vacuum motor that drives the mode lever has 2 nipples. IT is a drag to get to but you have a 50/50 chance of getting it right, and if wrong, it will work the opposite of what it should. Or, you can looK up the colors and charts, which I would recommend of course!

In any event, it is really not that hard to do after you look at it for awhile, and when it is working, it is very good!

[hippymill]

vac lines are connected on the t-case. crawled under to check tonight. don't get it. it should be getting vacuum off the small nipple on the pcv, shouldn't it? if not where does this connection go?

[Ernzo]

Link here:

http://www.ifsja.org/tech/tcase/seltrac.shtml

Hmmmm, the vacuum from the PCV ought to go to the reservoir. From there, as I recall, the red line goes into the firewall. I would check to ensure that you have vacuum in the green/yellow lines. I assume the 4x4 is not engaging? Have some one switch the lever while you lie underneath and look.IS it moving? Is there any movement at all? BE sure the jeep is in PARK, Brake on and wheels chocked. Never make the mistake of not adhering to generally accepted safety rules. A friend was killed here in Denver (not a jeep guy..) when his floor jack gave out and his sons wheel without the tire (brake job) fell on his chest. Jack stands, and he is alive today. Terrible.

[fulsizjeep]

Over time the yellow and green plastic tubes get very brittle. Mine worked fine until the tranny replacement and I discovered they had crumbled, so used new rubber hoses in place of the plastic and that fixed the vacumn problem.

[lil' red wagon]

I am not sure if yours has the select-trac or not , but I just added vacuum diagrams that I used for my 83 wag to my gallery at fsj world

[lil' red wagon]

sorry I did not do that right

[kenny1221]

I have a similar problem. Switched trany and motor in my 89 GW and now the vehicle won't move. When I put the xfer case selector in neutral and the transmission in gear and try to put the xfer case into hi or low I get a grinding noise. This tells me that the tranny is turning . I also get the clicking noise when I try to go back to Park. But after I shut the engine down and engage the transfer case I get no response. Is this what yours is doing H M? I'm not trying to hijack this thread but your problem sounds so similar to mine and I really want to get my Jeep on the road. My Vacum lines are corect and working properly. Any Ideas?

[hippymill]

mine simply won't engage. no grinding, etc... I do get the small hiss when i flip the switch inside the cab. I will do the check on the t-case vacuum motor tonight(wife willing), and post the results.

[hippymill]

ok-vac motor does move when switch is flipped. doesn't move much, but i would assume that would be because the wag isn't moving. when i listen inside the cab as the switch is flipped it hisses like i'm used to, but will let out an extra hiss after a few seconds. it never did this before. could it be a small vac leak that is just enough to prevent the vac motor from fully engaging the t-case? also did the gravel test(gravel road and spinning tires) to see if maybe the light just wasn't working, and it definitely doesn't engage 4wd. I DON'T GET IT!?!?!?!?!

[letank]

if you have a hiss you have a big leak.....

if you have a vacuum gauge... how much vacuum do you have.....

try to connect directy a good hose between a good vacuum manifold source and your TC hose (bypass the switch) i suspect a big leak somewhere; the hose the vacuum or the switch......

yes even hose that look good... may be so porous ... that you will barely see any vacuum.... this is why a gauge is good.

Michel

[Ernzo]

Hippy. First, check to see that the vacuum motor moves in the correct direction. ie, when switched to 4x4, it pulls the lever forward. Then when switched back it pushes the lever back. A little movement is what mine does, however it does, in fact, pull / push it all the way, but I have to gun the motor a little and drive it a little as well. I would put it in 4x4, check to see that the motor pulled the lever forward, then quickly rev the motor / pulse the motor a little, drive it a little. Stop, turn off the jeep. Lie underneath and see if the lever has moved completely into the forward position. You can check it with a big screwdriver as a lever. There are adjustments, but I would not fool with them until you figure out if there is enough vacuum to engage / disengage. I would not drive much with knowing that it was either fully engaged or disengaged, just a little like 20-30 feet, slow. Another test is to try to pull the rage lever into low, it will only move if and when the unit really is in 4x4. Do not pull that lever too hard, and I suggest that you do it with the motor off, or in neutral. IF the range lever moves at all, it will pull up a little, and this is where I usually have to turn off the motor or she grinds to beat the band.

If, after all, the mode (4x4) lever will not really pull or push itself, then you have either a vacuum leak. The hissing at the switch is normal for me, when I switch there is a little hiss. It is fairly easy to take that select-trac switch off and check the manifold to ensure that it is fully engaged. If you do not have a vacuum tester, you can use the old "suck on the little hose and use your tongue to see if it will hold vacuum at all. On mine, the hidden leak was under the hood right at the firewall. I believe it was the accelerator cable rubbing against one of the colored hoses. I could not see it until I moved the accelerator hose away, and there it was! I (actually Michael from the CFSJA) simply cut the hose and spliced it with a piece of rubber hose and zip ties. Works great!!