Tell me more about this milemarker 16% OD kit

[2man]

Ok Jeepjake says that because my QT chain might be slipping it might be time for the milemarker 16% OD lockout kit. I have a truck with 67000 on the odom and i am assuming the QT is original with no work done to it. What does it do, is it worth it, is it cheaper than any other option, BUT MOST IMPORTANTLY IS IT A GOOD IDEA? I've got 5 days off and am ready to do it!! :confused:

[joe]

It essentially removes the clutch cones. So when the E-drive switch is in it's normal position you are in 2WD. When you engage the E-drive you are in 4WD. In 4WD you need to be on a loose traction surface etc. It makes it work just like a conventional part-time case like a D20 except shifting from 2H to 4H you'll be doing it with the vac switch rather than a floor lever. The 16% OD version does just that...adds an OD but to the x-case instead of the transmission. It in effect raises(lowers numerically) the gear ratio of the axle. It does this by changing 1:1 ratio of a normal QT to 0.84:1 in H/range but it also changes the 2.6:1 L/range to 2.18:1
Stock gearing on a 76 J-10 would be 3.54's(4.09's optional) so if you run the 3.54's your effective axle raio will now be somewhere around 2.97 Not real good gearing IMO :(
Pesrsonally I wouldn't recommend an OD unit for a rig unless it had at least 3.73 gears and preferably lower(numerically higher).
I don't know what the OD version of the kit goes for but the last time I looked the standard kit w/o OD was about $450 and don't know if that included unlocking hubs or not.

[2man]

Your right joe i looked at the mile marker sight and their own numbers talked me out of doing it. According to their RPM chart i would only be taching about 2423 with the 32's im going to be adding. Great fuel mileage but not to good performance wise. Guess I'll just rebuild the QT and install the 32's to help a bit on the road mileage. Thanks again for you insightful info. BTW the info on RPMS with tire size and the 16%overdrive is at:4wheelparts.com (http://www.4wheelparts.com/Tirel_gear_ratio.asp)

[joe]

There's also the option of the conversion kit in the standard non-OD vesion that won't effect your overall gearing.

[2man]

Maybe thats the way to go. Its 2wd while in normal and 4wd while in emergency?

[Mikel2]

Well... Myself I'm a BIG fan of the good ol' QT. I loved it while I had it in my truck, and I sure wish I could mate one to the T-18 I have now. If I were you, I would just change the chain in your QT and keep it as it is. Good luck.

[joe]

<BLOCKQUOTE>quote:</font><HR>Originally posted by 2man:
Maybe thats the way to go. Its 2wd while in normal and 4wd while in emergency?<HR></BLOCKQUOTE>


Yup ;)

[78WagLimited]

2man.. I converted my '78 over back in April... Bought the Mile Marker kit and Warn hubs from 4 Wheel Parts, about $400.00 for those parts..a new chain from Border Parts in San Diego, CA for $100.00.. It's an easy conversion..

[nightflyers]

Mikel2 is right, The QT is a good t-case. The only thing is you will probably run into a messed up cone in the diff. The cones are no longer made and are hard to find. Mine were so messed up that I could spin the rear yoke by hand. you may want to test it before you take the case out. The milemarker kit eliminates the ceter diff so you don't have to worry about the cones.

[Mikel2]

Hello again,
As Nightflyers pointed out, parts for the QT are getting hard to find, but vehicles with QT's are still plentiful in the junkyards. When the cones in a QT wear, you end up with a central open differential instead of a LSD. But you can still lock it using the E-drive anyway. One of 1FSJ's members wrote an interesting page on the QT and the PT conversion: http://www.t-r-j.com/Auto/QT/quadratrac.htm