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Making Vacuum disconnect work with a 99 TJ T-case

Bronco

Bronco

NAXJA Forum User
Location
Swansboro, CA
I’ve hit one little snag. I’m swapping out my 87 BA-10 tranny for a 91 AX-15. (SEE http://www.naxja.org/forum/showthread.php?p=168577#post168577) I got a 99 TJ T-case to put in with my AX-15 so I didn’t have to mess with changing the Input spline thing out, but it doesn’t have any provision for the vacuum actuator stuff for the axel. What to do? I wouldn’t mind having a Posi Lock cable anyway so that may be a solution for engaging the axel, though I’d rather not spend the cash right now. I could switch my axel to a one piece to solve the problem as well; again I’d rather not spend the cash at the moment. Either of those options still leave me with the problem of the hoses being a Vac leak if they are not connected. I could swap the back end housing from the old t-case but that would really complicate the whole thing because I would have to do it with the jeep apart and I’m planning on having a shop do the bolt up, so how would I get it to the shop. I guess if I just leave it off for now it will be drivable if I could find a way to stop the leak. Anyone else run into this?
 
I didn't run into that snag but you could probably just shim the shift fork into the engaged position. I'm sure there's a post somewhere that says what to do but it should be fairly straightforward. I have no firsthand experience though.
 
Hey Mark, since now I have working knowledge of the dsico mechanism. I also have some spare parts if you want them. The inner axle another shift motor and all that.

Anyway, to lock it tempararily, I would just take off the shift motor nad just put a wedge on the fork to keep it form moving. Since your planning on maybe doing the posi cable thing anyway.

I can't take pictures of mine if it helps any.
 
I don’t really want to do anything that will damage the lines because I think I may want to fix the case to work with the disco some time soon; just not before I do the swap. I have the Lock right in the ft axel so I’m not sure I want to keep the axel locked all the time.
Dose anyone use the Posi Kit? How dose it deal with the vacuum lines?
 
May sound kind of off the wall but if you really are that attached to having the vac disconnect on that diff you could always run a vac line into the dash and put a vac switch in there next to whatever fog or driving lights you have. When we got the 89YJ all I saw was that vac disconnect as a problem waiting to happen and probably in a mother of all snow storms, in the dark and on a deserted road when I'm wearing a suit. I count my blessings my 98XJ an the two TJ's don't have them... I would manually lock it permanently by whatever means necessary.
 
It's really not that hard. You should have a vacum line connector near the passenger firewall that joins the lines coming up from the vacum motor to the switch down on the old transfer case, etc.
The red line is manifold vacum. Plug it if you want to wedge the vacum motor.
On the other hand, I believe that if you connect it to the yellow line, it should "pull" the vacum motor into the 4wd position and hold it there. If you connect it to the green line, it will move it to the 2wd position. The third line (I forget the color) on the vacum motor goes to the "part time" light switch. When the motor is in the 4wd position, vacum is passed to this port and goes to the switch. You will need to either leave it connected to the switch, or plug the port or line.

If you want, you could set this up to do it manually when you wanted to go off road. It would be kind of like getting out and locking hubs on other 4x4's.

I kind of recall that someone used an old manual vacum switch from an old FS Cherokee and ran the lines inside the cab. I simply used solenoids and put a switch in the dash. It works well and is a lot cheaper than the posi lok method.
 
By the way, what I was suggesting does not require any cutting of lines. You just unplug the connector at the firewall and connect vacum tubing to it there. If you want use the transfer case switch again, just pull the lines off and reconnect the original connector.
 
The posi lock is a real easy install, and Collins Bros http://www.collinsbrosjeep.com/main.htm has it for $159.95, which I'm betting is far less than what you'll be paying someone else to install that tranny & tcase.
Mike B.
 
It's great, I never have to worry if it will work or not.... I like nice solid mechanical connections vs the vac or elec stuff that is getting so popular. Hell I even had one salesman try to talk me into getting that goofy ass electric shift tcase when I ordered the myself a new F350 PS last week, he even tried to argue that it was better???? Needless to say I went elsewhere and even got a better deal... but that's getting way O/T, sorry.
 
Hey Bronco, i don't know if you want to spend $130 on some wire so you can actually engage your axle to 4X4, i was thinking about it too when i got in situation where i had no vacum from T-case. Here is what i did, i went on e-bay and bought 3 way vacum switch 12 volt so what it does it switches vacum from one oulet to another with just regular swich that you can wire up to vacum switch. On the axle disc there are 3 hoses coming out of there you only need too one is just a breather i gess, but other two is the way to controll your locking or unlocking axle. So my set up costed me about $27 and now i can go in to 2low or 4low with just a switch, here is the link to a Vacuum selenoid i got: http://cgi.ebay.com/ws/eBayISAPI.dl...4&category=4660&sspagename=STRK:MEBWN:IT&rd=1 you can get something simular to that and use it very effectevly. If you want me to give you full write up just PM me.


Rodion
 
gtride said:
Hey Bronco, i don't know if you want to spend $130 on some wire so you can actually engage your axle to 4X4, i was thinking about it too when i got in situation where i had no vacum from T-case. Here is what i did, i went on e-bay and bought 3 way vacum switch 12 volt so what it does it switches vacum from one oulet to another with just regular swich that you can wire up to vacum switch. On the axle disc there are 3 hoses coming out of there you only need too one is just a breather i gess, but other two is the way to controll your locking or unlocking axle. So my set up costed me about $27 and now i can go in to 2low or 4low with just a switch, here is the link to a Vacuum selenoid i got: http://cgi.ebay.com/ws/eBayISAPI.dl...4&category=4660&sspagename=STRK:MEBWN:IT&rd=1 you can get something simular to that and use it very effectevly. If you want me to give you full write up just PM me.


Rodion
Click to expand...

Third line is to activate the switch which lights up the 4wd light in the dash.
Mike B.
 
Well I like your suggestion and I’ve been considering that kind of an approach. I was looking at http://www.mcmaster.com/ PN 5360T11 and my bro is sending me a 73-79 center dif e-drive switch from a quadra-trac. Using a valve like this would have the advantage that I wouldn’t have the constant current drain when the solenoid in active, on the other hand it would be somewhat more complex to run the vacuum to the dash to use this switch.

Can anyone give me a bit more info on the roughing of the lines? So the red one runs straight from the Manifold back to the T-case switch. The yellow goes from T-case switch to the side that will lock the axel. Green moves it to the unlocked position. The other one should be hooked to the yellow one to turn on the light. Dose that all sound right?

With the posi lock, where dose the cable come through the firewall and where do you mount the lever? Anyone have pics?
 
why don't you just build your own "posilock" search the net there are plenty og good writeups using a choke cable to engauge/disengauge the axle

this might cost you $15 if you go all out
 
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