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79chiefs 12-06-2012 02:22 PM

79 Cherokee Chief TRASNFER CASE HELP
Ok... so I have been working on a 79 cherokee chief I found in the woods and bought. I am in high school so I cannot afford to do a lot i bought some tires for it but 2 were bad. I put them on to replace two that were originally on it and wouldnt stay up. I know I cannot drive it with two different size tires on it, because it is the Full time Quadra-trac High/Low range, and it may burn out a differential. I took the front drive-shaft out to drive it but now it will not lock into any gear, and grinds when I put it back to park. I read i needed to put it in E-drive, but I do not know how, and I also looked at the wiring diagram and found that I do have the wiring for it on the t-case, but I think the bulb was out of the spot in the dash, when I took it out to replace some gauges, also I know it is supposed to be a orange wire which is also the color of other light bulb wires, and I found one cut under my dash. I do not know which wires go where, for lighting, also do not have lights to light my dash up when i pull the headlight switch. next I looked at the vacuum diagram and found on vacuum hose just dangling coming from the engine bay with one other. The e-drive diaphragm has the two vacuum hose hook ups on the t-case, but they only have on hose that connect the two hose hookups. I need to know how to put it in e-drive and how the vacuum hoses are supposed to go. It has and engine swap from 360 to chevy 350(79-year), with th400 trans, and Full time Quadra-track with high/low range. PLEASE HELP

jeepdaddy2000 12-06-2012 04:54 PM

The E drive is vacuum operated through a switch in the glove box. You will want to inspect the vacuum lines going from the engine through the switch, down to the vacuum motor on the top of the t case.
If everything is intact, start the engine and rotate the switch to see if the bulb comes on (e drive engaged). If so, you are in business. If not, place the transmission in gear and see if the rig moves. If it does, then the bulb is most likely out. If not, or it moves very slowly (do not drive it this way or you will destroy the ls in the t case), then put the trans in P and check for vacuum at the vacuum motor to see if the switch is working. Check both sides, since sometimes they get switched. If nothing, then work your way back till you find the leak. If you have vacuum and the e drive won't engage, then the vacuum motor may be bad. Try getting it to move with a vacuum pump. You can pull the motor and move the arm by hand if you have to in order to get the rig moving.
If all you are just moving the rig a short distance, reinstall the driveline. It won't hurt to drive it in poor traction conditions or for a short ways on pavement as long as the tires aren't ridiculously different in size.
Here is a pict of the motor and cover,
Here is a schematic of the vacuum lines.

79chiefs 12-07-2012 01:57 PM

I understand what i need to do, but i have no glovebox behind the glovebox door just bunches of wires, also no switch, but just a sticker telling me how to do it, also when i took the dash out to replace bulbs, i noticed a cut orange wire, and not light ion the e drive slot. Under the jeep there is a vacuum line not connected, and a vacuum line connecting the two vacuum hookups on the diaphragm, i was going to try to connect that vacuum line directly to the activate side of the diaphram

79chiefs 12-07-2012 02:21 PM

Also can you tell me what exactly i can do with e drive, because i have heard a lot, like it disengages the front driveshaft because that is what i want because i have the drive shaft out to be able to drive with two different size tires till i can afford to get a whole set, b/c i do not want to burn up and of the drivetrain being it is full time 4wd or can i just stay in normal to do this or do i need to be in e drive to drive without the front driveshaft

jeepdaddy2000 12-07-2012 08:20 PM

You can drop the front driveline and safely drive the rig with the e drive in the emergency mode. This will cause no real problems unless you have an LS in the rear diff (a large difference in tire size side to side will cause the LS to work). You will also want to stay off the throttle, as only half of the driveline will be pulling.
You can not drop the front driveline and drive without engaging the e drive. If you do you will destroy the LS diff in the t case.
If you apply vacuum to the engage (inner) side of the motor, it should engage the e drive. You can do this by connecting the vacuum hosed directly from the manifold to the vacuum motor or with a vacuum pump.

79chiefs 12-26-2012 07:25 PM

I tried to put the vacuum hose directly on it but no difference also when i try to drive with the dhaft out it does not want to move, also what is LS mean

RockRollin 12-26-2012 08:10 PM

Limited Slip(front to rear). I believe the e-drive locks it in place. You may have to remove the vacuum motor from the t-case and get it freed up and moving easily. Check the diaphragm for leaks.

79chiefs 12-27-2012 01:11 PM

How do I check for leaks i just finished putting the driveshaft back in(finally had some time to), and i made sure the vacuum hose from the engine bay is hooked to the apply side, but i am waiting for my battery to charge a bit before i start it, since I cannot seem to find a battery that does not die when in this jeep. I have redone wiring and it does not die as quickly but still. Also how do i know if my e-drive is engaged, because as i mentioned in earlier posts i have no light in my dash and do not know which of the cut wires goes in its place., next I have on orange wire in the dash cut how can i tell if its the e-drive wire, because it disappears into the wiring harness.

RockRollin 12-28-2012 04:00 AM

Could use a vacuum pump, could compress and hold finger over hose nipple to see if it holds at release. I'm not real familiar with QT , but it will not go into low range if not locked into e-drive, from what I've read elsewhere.

CSP 12-28-2012 08:08 AM


Originally Posted by RockRollin (Post 14686390)
but it will not go into low range if not locked into e-drive, from what I've read elsewhere.

That would be incorrect. There's nothing to prevent it going into low range that has anything to do with the e-drive.

olliehopnoodle 12-28-2012 11:37 AM

How big of a difference are the tires?

You don't want to just hook the t-case up to manifold vacuum. If you do it will jump in/out of e-drive basically everytime you put a load on the engine. To keep it in edrive you want to hook it up to the vacuum canister. The canister maintains a vacuum even when the engine is under load. You will want to test to make sure it is working.

Best bet is get some tires that match. It will be cheaper than buring out your T-case.

79chiefs 12-28-2012 11:53 AM

They are 31's on front 32's on back, also how do i know when its in e-drive

olliehopnoodle 12-28-2012 02:06 PM

I am not sure how you would know for sure, especially if you bypass the system. I don't know that running it in E-drive is a good idea either. If my understanding is correct, E-Drive 'forces' the front/rear drive shafts to spin at the same speed. If the tires are different size it is going to bind/unbind over and over.

How much do you expect to drive it like this?

RockRollin 12-28-2012 04:29 PM


Originally Posted by CSP (Post 14687026)
That would be incorrect. There's nothing to prevent it going into low range that has anything to do with the e-drive.

Right, just reread. I'm off:o .I'll take the cotton outta my ears and stick em in my mouth and listen;)

Dumpy 12-29-2012 06:45 AM

Easiest solution is to replace all the vacuum lines, and find an EDrive glove box switch. Sign up at IFSJA and post on the wanted section. You CAN drive with EDrive engaged, without the front drive shaft. The Quadratrac is an excellent system as long as its been maintained. Make sure you put the correct fluid in. You can get it at BJ's off road. ATF will destroy it. Yu can also get a new glove box insert at BJ's. They Are cardboard from the factory. They offer cardboard and plastic. Don't hurry this and ruin it. Get the correct parts, make sure it works as it should, then drive it.

For IFSJA, make sure you read the READ FIRST section, and email Tad, one of the moderators, and he will let you on. He's the manual spambot filter.

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