I have 2 questions I have read up on here about the q-trac system. Which there is some really good write ups explaining what the function does.
My first question is,
I have been playing with the switch in the glove box. I turn it one way and I hear a vacuum noise and turn it the other way it goes away, although I dont feel a difference in driving it. The light stays on saying Emergeny drive which I know is directly tide togother. Since nothing seems to change when I drive it with the switch either way. Is there a vavle that could be plugged, or something else I should check next? I have followed the vacuum all the way thru and it seems to be there.
I have been playing with the little lever on the floor next to the drivers seat. It should change it from H-N-L or visa-versa. If I put the transmission into nuetral and move the lever from HIGH to LOW, and then put the transmission into drive it does nothing. When I out it back into PARK to change out of the gear, it grinds and then will make a popping noise before it shifts. What could be the problem? any ideas?
Its a 1976 with a 258, and has a 400 trans, with q-trac.
I still haven't mastered shifting mine with the engine running. I find it easiest to turn the engine off to shift from low range to high range or vice versa. Sounds like you aren't getting it from neutral into low.
If you hear a vacuum noise with the switch in any position, you have a vacuum leak, which is probably preventing it from unlocking the transfer case (or locking, but you indicate that the e-drive light is on.)
quadra trac is a full time 4wd system. It has to be in high when you are driving around town. The low gear is used off-road (generally speaking). When in either high of low range, the transfer case acts like a limited slip differential. It sends power to whichever axle (front or back) that isn't slipping. The vacuum operated switch in the glove box locks the transfer case. What this does is send 50% of the engines power to the front and 50% to the back, no matter what kind of conditions you are in. You should never drive the jeep with the transfer case locked on dry pavement unless you have lots of time and money on your hands.
I hope this helped.
2009 JKU Rubicon. stock now.... I'm working on it.
Does the emergency drive engage or disengage by the vacuum being on or off?
Kinda, it the vacuum pulls on either side of a rod on the transfer case. It pulls it in one direction to lock it in e-drive, and pulls in the other direction to pull it out of e-drive. Once it is in one mode or the other, the vacuum is no longer needed to hold it into position. While the switch could be leaky, I'd say it's more likely that a hose is loose behind the switch.
A brief description: A vacuum hose runs from the intake manifold (providing vacum) to the switch. Two hoses then run from the switch to the transfer case, one to engage e-drive and one to disengage e-drive. They attach to the transfer case on the upper right side. When you turn the e-drive knob, vacuum switches from one hose to the other.
AJeep, just another thing for you. If your vac. hoses are all good and you find no leaks, the shift actuator on the xcase can go bad and not shift either into or out of E drive. But it does sound like you have a vac leak at the glovebox switch.
Seems like everyday is a Monday.
Thanks for all help and ideas, now I understand how it all works and that helps when I am trying to resolve the problems.
The switch for the glove box had the three lines in all the wrong places. So after moving them all around, that was fixed.
After being explained about the shift actuator. I double checked it and there was a vacuum leak fixed it and now it works.
Still cant shift from HIGH to LOW or visa versa, with out shutting it off and then changing gears. Does any one have any ideas on how to fix this? It just grinds if I dont shut it down and then restart it.