1984 Grand Wagoneer Transfer Case Stuck

[teardrop74]

I need some help (besides my mental stability); Got my truck back from the machine shop and it appears to be stuck in low range. I have been poking around the threads and could not find an answer to my question so here it goes.

The Jeep is on the 2wd setting on the dash switch and when I set it in park and engage 4wd you can here the vacuum line hissing behind the dash but it continues to hiss unless you switch it back to 2wd. However....if I move the transmission into neutral I can select between high and low range but it appears to do nothing. When I get it on the road it only wants to go about 30mph and nothing more...so I feel like it is stuck in low range.

I have been reading up and a lot of GW it seems suffer from vacuum line related issues to the transfer case and the 4wd system. My mechanic is trying to tell me that I need a new transfer case.

My question is could it be stuck in 4wd low due to a vacuum leak AND would it still allow me to engage / disengage 4wd high and low? Any help is appreciated.

Kris

[The Colonel]

You have a NP229 case, correct?

If so, the vacuum controls the 2HI and 4HI. The lever controls low range. There is a detent in the TC that shouldn't allow you to switch into low range unless it's in 4HI first.

Take a look at the troubleshooting here:

http://oljeep.com/edge_tcase.html

BTW: Welcome!

[teardrop74]

Thank you for the reply;

AFter further inspection NONE of the vacuum lines are hooked up to the transfer case. It appears the machine shop disconnected them when they pulled the block and did not hook up the lines.

The metal lines running from the vacuum motor tot he TC are not hooked to anything but the interior switch still seems to be getting pressure.

However I can still pull the lever in neutral to engage low and high gear...but I do not think it is actually doing anything.

[Chevelleguy]

When the lever is in HI, it will still only do 30mph? Does it feel like the lever is even hooked up to the transfer case? If it feels like the lever is moving something, and it is indeed hooked up, someone may have bent or broken the shift fork in the transfer case. It has to be in HI before you can shift it back to 2WD.

If you just can't get it figured out, or need someone else to fix it correctly, take it to David Yackley at Texas Auto Gear. 281-448-4371. He is on the north side near Gulf Bank.

[joe]

The switch is first in line from the vacuum reservoir. While you're hooking up vac lines check the one that controls the front axle too.

[teardrop74]

Okay this is what I am seeing; Start the Jeep and it says it is in 2wd....pull the switch to 4wd and endless vacuum hissing comes from the switch and no light on the dash saying it is in 4wd. I can then (in both 2wd and 4wd) set the TC into low or high (and it feels like it is moving something....I can feel a mechanical clunk when i switch between the two)

The steel hardlines are completely disconnected at the top end of the motor (literally laying along the motor) and the lines coming from the switch through the firewall appear to be hooked into the intake manifold and to various other lines.

Also the lines to the front axle do not appear to be hooked up as well....it looks like the machine shop just disconnected everything and did not know how to put it back together. I am tying to find a good diagram to re-pipe the vacuum lines to get pressure to the axle and the TC.

I was under the impression that if I had no vacuum running to the TC is would not allow me to engage low range.

[teardrop74]

Okay; this is the layout I am dealing with can somebody explain this to me:

http://oljeep.com/gw/vac/84-86/selectrac_vac_layout_84_85.jpg

In the diagram above...does #18 go to the front axle? I have three vac lines coming out of my diff and I do not know where they should go.

Also from the lines coming from the switch through the firewall...the red one goes to the vac canister correct? and the blue and yellow lines go to #17 on the diagram correct?

[Chevelleguy]

That is a parts diagram. There is a much better, routing diagram that you need.http://oljeep.com/gw/vac/axle/83-84-...tAxle4-whl.jpg I will give you a rundown of how the system works.

Manifold vacuum goes to a reservoir under the hood then to the switch under the dash. From there it goes to the front axle (through the metal lines next to the engine). When the front axle shifts (and only after) it sends vacuum to the mode selector motor on the transfer case. Once the transfer case shifts to 4WD, you can then shift to Lo range. You can only move the range lever when the case is in 4WD.

You mentioned that there was no light on your dash. My '83 did not come with one as there is no switch or a provision for one in the transfer case. There is a spot in the dash (far right hand side) but this was for other years and case options. I have a 208 in the garage that I got out of an '82 that does have a switch in the case.

[teardrop74]

Okay that makes a lot more sense, thank you;

Now see if you can answer this; If I can move the transfer case lever into low range even though the switch on the dash is in 2wd does that mean the jeep has to be in 4wd somehow? Or could the transfer case just be busted?

Whoever hooked the vacuum lines up ran the green output from the switch directly into the front differential vacuum pump and ran the yellow line from the switch directly into the transfer case shift actuator and bypassed hooking up the steel vacuum line system that is stock.

The part that I am getting confused on is that I can move the TC lever into low range even though the switch is set to 2wd but it will not let me go into hi range (no matter what I try). I am going to go get new vacuum lines this afternoon and attempt to hook up the system to the stock method and see if that solves my problem.

Does any of that make sense?

[Chevelleguy]

You say you can move the lever, and it feels like it is doing something. Does it go into neutral? You have three positions, 4hi (down), neutral, and 4lo(all the way up). Try shifting it with the engine off and the tranny in neutral to make sure nothing is binding. If you can't get it into 4hi, you will never be able to get it into 2wd, doesn't matter what the dash switch says.

With the way the PO had it hooked up, I am going to bet that the transfer case is going to be toast. But you need to get the vacuum lines run correctly first.

[teardrop74]

Okay...all afternoon under the waggy:

The PO had the system completely backwards; the green vac line (which was spliced onto a manifold line that was receiving constant vac) from the switch was run directly into the axle and the yellow vac line was run directly into the transfer case (backwards I know) with all of the stock setup removed.

So I am assuming, with the green line going directly into the t-case with contant vac pressure...that is how it was able to engage low range without going into 4wd....with constant vac on the t-case shift motor....it was thinking it was in 4wd.

I replaced all of the vac lines and got the stock system up and running....from the manifold to the vac canister down to the axle and back to the transfer case.

Flipped the switch and finally it engages 4wd (transfer case still stuck in low)

I took for a test drive and I can def tell its in 4wd now....a lot more power when i take off...not dogging out. I stopped the truck, put it in neutral....set the swith to 2wd....pushed the transfer case down into high range and it started to drive when i put it in gear....then it slipped out.

So now I think I need to adjust the throw of the shift arm for the transfer case and see if it still stay in high range. I agree that the transfer case might be toast but I will keep trying to see if I can get it to work.

Thank you for all of your help.

[Chevelleguy]

It didn't THINK it was in 4WD, it was. The difference being that the front axle was being unlocked as the vacuum was routed wrong, so it acted like 2WD. Try pushing the lever down while the engine is off.

[Suddendeath]

This thread confuses me...

You should have a NP229/228 with the vacuum-disconnect front axle. If your transfer case was in 4x4 this whole time and your front axle was disconnected, your viscous coupler would be shot/dying and the truck wouldn't have moved at all...let alone at 30mph. Read to the bottom please, extra info added in.

Do me a favor and try this out...

1) Get under the truck and disconnect the transfer case vacuum shift motor from the linkage that goes into the TC

2) Put the transmission in neutral. Crawl under the truck and grab the linkage the vacuum shift motor was attached to. Push it towards the rear of the truck. THAT is 2wd.

You will feel it lock into 2wd. If it won't go, then you're stuck in low range and need to do this...

3) Look "Up" past the 2wd/4wd linkage and you'll see where the shifter arm comes through the floor for the Hi/Lo. Grab it and push it to the rear of the truck, see if you can move the transfer case out of lo (farthest setting towards front of truck) into Neutral (middle setting) or HI (farthest rear setting). If you get it into HI, go back to step 2.

If the Hi-N-Lo linkage refuses to move, you will need a friend for the next step.

4) Have a friend sit in the driver seat. DO NOT BE UNDER THE TRUCK FOR THIS. Start the truck in park. Shift into drive and let the truck drift forward a few feet. Stop the truck with the brakes and shut it off with it in drive. Then go back to step 3. DO NOT put the truck in park, have your friend sit in the driver seat with his foot firmly on the brakes. This tricks the truck into letting the HI-N-LO lever shift with the transmission/transfer case in a meshed state.

It sounds like you have a classic case of poorly adjusted/tightened linkages and a bad vacuum shift motor. Virtually all of the NP229/228 vacuum shift motors I've ever seen have been bad, so I always like to think they're dead on arrival.

Good luck, let us know how it turns out. If none of this works for you, and the linkages are all telling you that youre in 2wd and the truck is still acting goofy...then you probably toasted your viscous coupler/transfer case.

EDIT:

Check your transmission control lever that hooks up to the carb. After thinking about this for a few more minutes, your problem may not be getting stuck in low range...you may not be shifting out of first gear. Take it for a drive as it is right now and listen and feel for the 1-2-3 shift, even in low range it will shift through all 3 gears. If you dont feel any shifts, then you're stuck in 1st gear and need to adjust your transmission control linkage.

[teardrop74]

Did your adjustments; I think the transfer case is toast.

The shift motor arm was bent to hell and I believe the motor itself is shot. Got under...made the adjustments....it went into hi range...i started to back up and it slips out and does not make connection....rolls back like its in neutral.

Low range still engages for some reason.

The transmission is a newly rebuilt transmission and it does shift through the gears even in low range so I don't think that is the problem. I think whoever hooked up the system wrong drove on it and just trashed the system.

Time to start saving some money.

[Suddendeath]

Did your adjustments; I think the transfer case is toast.

The shift motor arm was bent to hell and I believe the motor itself is shot. Got under...made the adjustments....it went into hi range...i started to back up and it slips out and does not make connection....rolls back like its in neutral.

Low range still engages for some reason.

The transmission is a newly rebuilt transmission and it does shift through the gears even in low range so I don't think that is the problem. I think whoever hooked up the system wrong drove on it and just trashed the system.

Time to start saving some money.

Just trying to help ya trouble shoot and save some $.

Hand-shift the transfer case from under the truck like I described in step 1 and step 2 above. Make sure that it's all the way towards the rear of the vehicle with the transmission in neutral and the transfer case in 4x4hi. That will set you into 2wd. If you still have your slipping problem, then your transfer case is toast...but I've never heard of them going out the way youre describing. The viscous coupler is a center differential that prevents driveline bind when youre in 4x4 on the street. If the front axle is accidentally unlocked and youre not in 2wd and actually in 4x4hi all of the power will get sent to the front axle, creating the slipping problem you're describing. Make sure the truck is actually in 2wd, or make sure your front axle is completely locked-in while youre in 4x4hi.

Your front axle disconnect may be shot, preventing the front axle from engaging and causing the VC to slip.

Edit:

Check this website out, its all about the front axle disconnect system. I know it says Cherokee XJ, but the system is basically the same.

http://jeep.zerok.ru/index.php?page=180