[jjh40]

I suppose this question has been by you guys a hundred times already, but how about once more. Can I put lockouts on my 79 quadratrac cj-7 and get two wheel drive, or do I have to spend all that money on a two wheel drive conversion kit for the transfer case? I have one other question too. I don't have the low range on my Jeep, can I install one off another Jeep, such as a waggoneer or something? If so what years and models should I look for in the junk yard?

If your kidneys don't hurt, it's not a real Jeep!

 

[291]

I have only done it with the part-time conversion kit, was worth the $$ to me

/wwwthreads_images/icons/cool.gif Big Ed
'88 YJ, 4" susp,3" body,33's,283 Chevy V8,TH350,4.11's,D30,D35c

 

[CJDave]

/wwwthreads_images/icons/cool.gif Yes.....that would be a fine idea. What you would do is flip the case to "Emergency" drive, and lock the center differential. That way, the front shaft would tumble but would not be hooked to the wheels because of the Warn hubs. The advantage here is that it removes any binding that is caused by tire mismatch, and is a little easier on the drive train and on the fuel consumption. We have considered this on our CJ as well, AND....it makes it possible to TOW the Jeep with the rear wheels up if you had to. We use a fixture that I invented for checking the tire rolling radius, and we get them PERFECT to avoid wasting fuel, both on our '79 CJ7 QT TH400, and on our '97 ZJ Select-trac. Yes....you can add the low range on your lunch hour at work in the parking lot. Be aware that it will make more "slop" when you drop it in gear due to the wear on the planetaries, but there is really nothing that you can do about that. We think Quadra-Tracs are cool/wwwthreads_images/icons/cool.gifand are modifying ours to be totally open center to run in snow and use less fuel zipping around town on the dry./wwwthreads_images/icons/cool.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[035]

hey CJDave,
how about putting 4 lockout hubs on "Snojeep" would make it nice to tow (i'm sure you could buy a trailer for the price of this/wwwthreads_images/icons/smile.gif) i would guess you would want to carry a couple spare "drive flanges" in case you blow a hub, my thinkin is one stripped hub and you would be stopped cold? (with 2 open axles and an open transfercase)
also about all i know about a "Quadratrac" is that it's got an open differential in it somehow.
after re-reading you post, could you please expain to me (in layman terms) how you can "lock" the open diff. by going into "emergency" drive?
i'm just curious.

3/4tonYJ
My Jeep Page

 

[Guest]

In normal driving the quadratrac distributes torque between the front and rear. Unfortunatly it's like an open diff in that it sends more power to the axle with less resistance. It works good in the snow though. When you turn the switch to emergency drive there is a vacume operated fork that slids a coller and locks the front and rear together so it no longer floats. My buddy had a quadratrac behind a 360 and the vacume fork would not hold the torque of the motor, it woould pop out under full throttle, we never did get that thing to work right. I ran lockouts on my quadratrac when it was still in my jeep. Just lock it in emergency drive. Of course my tranny blew about a week after installing the lockouts but I don't think they were connected, the tranny had been whining for years.

Al
My web page

 

[CJDave]

/wwwthreads_images/icons/tongue.gif It did not take me long to determine where the weak point was in the Quadra-Trac system. In order to make it so the driver had LESS CHOICES to make, they put in some cone clutches in the center differential to make it TRY to lock up a little when you give it a lot of power and one axle has very little traction.....like pulling out of a service station with gravel on the pavement......so the stupid driver just had to sit there and the transfercase does all the work....theoretically..... BUT the PROBLEM is that the center differential holds A LITTLE BIT, ALL THE TIME. And that makes the system sort of "tight" due to tire mismatch. Every time the stress builds up to a certain point, the clutches POP loose and the differential gears move all at once to a different spot. If you are trying to engage "LOCK" or what is called "Emergency Drive", the teeth on the slider cannot ease into the differential housing, but must wait till it slips, and then try to get in. Usually the clutch POPS ahead too far and the vacuum operated slider just gets a corner of the spline and any power applied just blows it back off. FOR THAT REASON, we are disabling the clutches and going totally open center just like the '97 Grand Cherokee that we love to drive in snow so much. It has open center and can be locked manually. On our Quadra-Trac we are also setting up a cool indicator lamp system that shows: Green-Open; Yellow-Has vacuum signal but has not shifted as yet; and Red-Locked. That way, Jeepchick will know when to stop turning figure eights to get the vacuum operated collar in or out. She will select the mode, and watch for the yellow to turn to red or green before she gets back on the throttle. It's a great transfer case, but those clutches have GOT to go! /wwwthreads_images/icons/crazy.gif And yeah, we DID consider rear locking hubs, but we would also have to go to full floaters. If you blow the rear hub or axle, you CAN come home in front drive, with or without the rear driveline if the QT case is in "lock"./wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[Guest]

I had a quadratrac and drove it for a couple of years before I converted it to part time. I bought the kit with a different gear
ratio. To me it didn't help the gas mileage at all. In fact I had to learn to drive the jeep all over again in snow. It was nice
driving down the road and hit a patch of snow and not worring about swapping ends.

 

[Guest]

all you qt guys, i have a freshly rebuilt one with a part time kit for sale. everything in it new. email [email protected] if interested or know someone who is.

 

[CJDave]

/wwwthreads_images/icons/smile.gif Yeah....glxdriver sold me his pull-out differential from the Quadra-Trac, and if the part I bought is any indication, that case was only driven to church on Sunday.....with an egg on top of the throttle pedal......it was absolutely PRISTINE!/wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[Guest]

Thanks Dave, how has it been working for you?

 

[CJDave]

/wwwthreads_images/icons/smile.gif We have not driven the CJ since we re-did the Quadra-Trac. Our own differential looked like it had been through a war, and we did not want to invest in a the machine work necessary to "open" the differential unless we had a real good unit. Your QT, as I said....was a real creampuff. At least the part we got was. We are dyed-in-the-wool snow drivers and we wanted all-four-all-the-time with an open differential, so Quadra-Trac was the way to go as long as we could disable the clutches and get completely "open"./wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[WILL]

for what it's worth, here's my setup. i have lockout hubs on the front axle and leave one hub unlocked and the transfer case locked most of the time. with the low range unit there is a lot of driveline slop, but i just take it easy when going from forward to reverse.

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner

 

[CJDave]

/wwwthreads_images/icons/smile.gif Sounds good to me..../wwwthreads_images/icons/smile.gif You are saving the differential in the QT case from needless wear that way. Do be sure that your front tires are "matched" perfectly to the rear, however, so that the front differential gears are not needlessly turning. If the engaged front wheel is a perfect match to the rear, there will be zero differential action in the front./wwwthreads_images/icons/smile.gif A buddy just bought a new Dodge FWD 3/4 ton pickup and it has 4WD Open...4WD Locked....4WDLo Range Locked. Im making him a fixture to "match" the tires because as he loads or unloads, it does change the rolling radius of the rear tires./wwwthreads_images/icons/tongue.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[Guest]

Im making him a fixture to "match" the tires because as he loads or unloads, it does change the rolling radius of the rear tires.
-----------
Question: How does loading effect the tire match. Though the radius would be distorted (lowering the center of the wheel under load), the circumference of the tire remains the same and therefore would turn at the same rate as the unloaded tire (one revolution of the axle = one revolution of the tire inflated or deflated) Am I forgetting something? I don't have a quadratrack, but was just interested in this fixture.

 

[WILL]

circumference is computed from the radius, not the radius from the circumference in the case of tires. the rubber will flex with the pressure and change the circumference. sort of like a balloon. the more air, the larger the radius and circumference. though a tire is not quite that exaggerated.

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner

 

[Guest]

True, but the vast majority of the flex is in the sidewalls, not the tread, and if you use a tape measure to measure around the circumference of the tire instead of using the radius formula, they would remain almost identical. I mis-spoke when I said deflated, what I meant was under load versus not under load, you have a different tire profile, but the same amount of air inside.

 

[CJDave]

/wwwthreads_images/icons/smile.gif The key word is "radius" the Jeep doesn't know what the circumference is...it only knows how far it is to the ground. As the "footprint" gets longer, the rolling radius for that same circumference decreases. The fixture checks from the top edge of the metal rim to the ground. Adjustments are made by air-up or air-down./wwwthreads_images/icons/smile.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.

 

[Guest]

Here's a test: Draw a chalk mark on the sidewall of your tire where it meets the ground and a mark on the ground. Now roll the jeep forward one full revolution and mark the ground again. Now air down a bit or add a load of bricks (2 tests really) and roll the jeep back one full revolution. Does the tire mark line up with the original ground mark? I'd bet it would because the circumference is the same no matter what the rolling radius is.

 

[Guest]

Lets do some extremes here... Your test sounds good, air up to 50 PSI, mark and roll forward, then air all the way down, pull the valva core, and roll back, will you test still work??? I dont think so. We went over this a while back, Effective crawl Ratio or something along those lines.


It was my undeerstanding that limited slips are the best thing to have in the snow, ice, etc. would it be possible to run limited slips in the F/R axles, as well as in the transfer case???

Later
BJ

to hell with it, lets go wheelin'

 

[CJDave]

/wwwthreads_images/icons/tongue.gif Well, David.....my moonguy-in-charge-of-slide-rules is kind of old/wwwthreads_images/icons/crazy.gifbut he STILL maintains that the tire does not act exactly as a tracked vehicle does where you have a given number of feet of track and a given number of revs of the drive sprocket. He claims that the tire "works" and the footprint changes enough to invalidate the circumferential method of calculating turns per mile. Try to remember the last time someone said: "Rolling Circumference" instead of "rolling radius". That's right, you've never heard of it; and my moonguy/wwwthreads_images/icons/crazy.gifhasn't either. Here's another test you could run. Noticeably deflate one tire on the rear axle of a brand new Dodge pickup equipped with the limited slip axle......Drive 200 miles......use the EPA smoke measuring system to check the cloud of smoke off the rear axle center section.......then check to see how far out to the axle ends the paint burned off. If it doesn't smoke and the paint's OK, my moonguy/wwwthreads_images/icons/crazy.gifstands corrected./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.