quadratrac transfer case

quadratrac transfer case

giantsfan

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lakehurst, new jersey
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79 cj7, 304 thm 400 automatic, quadratrac transfercase, stock rears.
i have a 79 CJ7 automatic with the quadratrac transfer case, couple of questions. is that a decent transfer case? if not what can i bolt up to be a little better? does anyone know if i can change out the air actuated switch to something a little more positive locking! was driving down the creek this weekend and got stuck cause the diaphram would not lock! :mad: looking for a lever type, any help would be greatly appreciated thanks.
 
I am not sure about what bolts in directly, but that is not a very sought after tc. It is good for on road, but not off. I belive you can get a cable actuator for the axle disconnect, i can't remember where though. I am sure someone on here will beat me to the punch with finding it.
 
Nothing bolts up in place of the Quadratrac directly. It has a unique tail shaft in the transmission and I believe a unique (or at least uncommon) bolt pattern to mount it. Any kind of swap is probably going to involve a conversion kit for the transmission at least and that means a new tail shaft which involves a complete transmission rebuild.

It's not a terrible t-case. Jeep put them in the full size Wagoneers, Cherokees and J-trucks. For the 401 V8 it was the only t-case available. The smaller engines could run a Dana 20 but the 401 would break the adapter. So it's plenty stout.

That being said, the vacuum diaphragm that shifts the differential lock is prone to going out and there really isn't a replacement available anywhere. And with the Quadratrac, there is no axle disconnect. It's a full time case with a viscous coupler on the front output. Disconnecting an axle will cause that coupler to blow out in no time. You can't even use locking hubs with it in full time mode.

Trouble is, that leaves you with only four options.

1. Live with an unlocked center diff
2. Force it into part time "E-Drive" permanently and rely on locking hubs to give you 2wd mode.
3. Build your own mechanical shifter by cutting up the one you have and adding a cable shift or electric solenoid.
4. Swap out the t-case for a Dana/Spicer 18 so you have the t-case outputs in the right place to match your offset axle.
 
Quadratracs came in 2 types, full locking and not, they were a great move in technology, just not a good case. Weak if wheeled hard.
also they have a few unique issues you will need to deal with when changing them out, such as offset of the rear axle.
research hear is the key, it will be easy to adapt a new t case to the tranny, 2 big companies offer kits, and as always drive shafts are going need to be ordered, it is just that you are going need a new rear axle if you do not go with a D18 t case.
 
Does anyone know of another lubricant to use on the quadratracs, instead of the special one that is only for them?
 
Thanks derf. I have another question for anyone, today I put my quadratrac in emergency drive, it engaged. I turned it off and it dis-engaged but the emergency drive light stayed on. It has been quite a while since I have put it in emergency drive. I was wondering if I forgot anything?
 
If the light stays on, it didn't disengage. There's a mechanical switch inside the case that triggers the light. You may want to check your vacuum lines and vacuum diaphram on the shifter to make sure they're not leaking.
 
thanks again derf, those hoses need replacing. hopefully that will do it.
 
Quadratracs came in 2 types, full locking and not

really ?
what years and models are you thinking of ?
they were all the same
they could be ordered with or without a low range unit
the low range unit could be added easily to one not so equipped
but " full locking and not" ?
 
I think you pretty much have to use an "approved" fluid because of the additives needed for the viscous coupler.

yes, you need the specified fluid.
no, there is no viscous coupler inside a BW Q-Trac
they are clutch driven units with cones
you might be think of the the NP series of transfer cases, 219, 229 etc.
 
really ?
what years and models are you thinking of ?
they were all the same
they could be ordered with or without a low range unit
the low range unit could be added easily to one not so equipped
but " full locking and not" ?

He may be thinking of QT units with the Mile Marker part time kit. It converts the t-case from an AWD/part time 4WD to a 2hi/4hi operation by replacing the clutches/cones on the front output (and probably a few other things as well).

But as far as I know, the factory never installed anything like that. The conversion was strictly aftermarket.
 

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