Selectable lockers, what's the skinny?

[csuengr]

Now the True Trac and all the diffs like it are NOT torque sensing, they are "Differential Wheel Speed" sensing. I'll post a pic so anyone following along can see, but most people see those sideways worm gears and figure an engineer hit it with a slide rule and it's full of magic that makes it sense torque.
http://www.summitracing.com/parts/dtl-9 ... 7AodrXwAeQ

Truth is, those are oil pumps. Helical gear oil pumps, so now do a brain exercise; Imagine you cranking a hand-crank oil pump, but over the discharge port is a pipe cap. Obviously, once you build up pressure, you can't turn it anymore because the outlet is capped. Now drill a very tiny hole in the pipe cap. Now the hand crank turns and oil squirts out the hole, but the faster you turn the hand crank, the harder it gets. That's how the True Trac works. The more differential wheel speed there is, the more oil it tries to pump and the more resistance there is to that differential speed. I often get myself in trouble for calling the True Trac the "ladies limited slip", but it's got tons of manly applicability, but they are all at speed, which is why they are so popular in rally racing and found in high speed performance cars. Now if you think about your mom, your sister, or your girlfriend/wife and picture them doing a three point turn on a dirt road and backing a tire into the ditch, what's the first thing they do when a tire starts to spin? If they're anything like the ladies I know and love, they floor it while gritting their teeth. Same thing with an iced over driveway, or after sliding into a snow bank, or accidentally driving into a mud bog. This is where a True Trac shines and why I call it a ladies limited slip.

Wrong. The Detroit Trutrac is a torsen type diff. Torsen being a contraction for torque sensing. There is no oil being pumped anywhere.

[REDONE]

Wrong. Torque sensing is a misnomer. It resists differential wheel speed, by pushing gear oil with those worm gears.

[ProTouring442]

Wrong. Torque sensing is a misnomer. It resists differential wheel speed, by pushing gear oil with those worm gears.

Actually, that's not true either.

The side gear is forced against the inside of the differential housing.

http://www.torsen.com/files/Traction_Co ... rticle.pdf

[ProTouring442]

For the non-geek (taken from the Torsen page)...

Okay, so tell me how the Torsen differential works in non-technical jargon! Top of the Page

This, by far, is the most commonly asked question. The Torsen differential is simply a torque multiplier that works through the use of friction generated by thrust forces from the internal gearing. It multiplies what torque is available from the wheel that is starting to spin-up or lose traction and sends that available torque, multiplied by the TBR, to the slower turning wheel with the better traction.


What happens when I have a wheel in the air? Top of the Page

As mentioned above, the Torsen differential is a torque multiplier. The Torsen requires some type of resistance or friction in the system to function properly. A wheel in the air provides zero torque or friction on the system and as the Torsen multiplies the available torque, zero, by its TBR, the end result is still zero. In response to this, we developed the Torsen T-2R with pre-load to combat those wheel in the air situations.

[tndonor]

Looks like Im the only one thus far with an OX. I run one in the front. As stated, it is beefy…… I was really impressed with how the unit was made. I wanted a selectable in the front when when i drove to the trails or my mountain property which was 50 miles from my house. Once I got to the trail, pull lever and presto. Most of the bad reviews I have seen about the ox are cable not shifting and cable set up. I would entire to guess that nearly 100% of those are folks who didn't read the instructions and tae the time to set the cable up properly. You can't have sharp bends (it is a push pull cable), and there are some tolerances with the shift fork and threaded end of the cable you have to measure (Im guessing most don't). Took me about an hour of fiddling and it works great.

The over nice thing is that in the event of an actuator failure, you can screw in a bolt and its locked back up. It was the only locker I found that had this redundancy. Will it ever be needed, probably not. Nice to know I can lock it up by hand threading a bolt……you bet

[haminawag]

Looks like Im the only one thus far with an OX. I run one in the front. As stated, it is beefy…… I was really impressed with how the unit was made. I wanted a selectable in the front when when i drove to the trails or my mountain property which was 50 miles from my house. Once I got to the trail, pull lever and presto. Most of the bad reviews I have seen about the ox are cable not shifting and cable set up. I would entire to guess that nearly 100% of those are folks who didn't read the instructions and tae the time to set the cable up properly. You can't have sharp bends (it is a push pull cable), and there are some tolerances with the shift fork and threaded end of the cable you have to measure (Im guessing most don't). Took me about an hour of fiddling and it works great.

The over nice thing is that in the event of an actuator failure, you can screw in a bolt and its locked back up. It was the only locker I found that had this redundancy. Will it ever be needed, probably not. Nice to know I can lock it up by hand threading a bolt……you bet

I'm assuming this will fit in either the front or rear axle? (D44s both) If so, do they give you enough cable to reach the rear axle? What is the inside lever assembly like, where did you mount yours, I have limited space in mine due to my obsessive radio hobby. Thanks.

[tndonor]

They do fit rears, I have seen a few TJs that had OX front and rear. I elected to stay with a detroit in the rear. Most people I have seen running an OX or ARB for that matter put a detroit in the rear as rear selectability versus what you can drive and live with out weighs putting in two selectables. As mentioned earlier, the ARB and OX replace the whole carrier with a stronger and better built unit with generally tighter tolerances. That is the main reason they are "stronger"

The shifter actuator is a little aluminum box with a throw handle. Mine is mounted in between the door and drivers seat and rollbar. It will fit in very tight spots. Ox has many cable lengths. I would imagine unless you have a crew cab something it could be done. If you fond my build thread here. jungle rot, towards the end there are a few pictures of the lever mounted on the floor between the cage and door. The shofter even screws down to positively lock it in.

[tndonor]

Forgot, you have to purchase your cable seperatley. They do not include cable becasue the applications are so varied..... I just measured and ordered.

[Jeeptchr]

I have the OX also in the front of my TJ. I got tired of adjusting the cable (installer, not me, didn't use loctite on the cable to shift fork connection) so I attached an air actuator to the diff cover in place of the cable and that solved all of my adjustment issues. We also have installed one on a buddies YJ that has the electric actuator, it still uses the cable but the actuator is mounted to the frame or fender, it works pretty good. He's happy with it. After running both full time lockers and selectables, I'll always spend the extra couple hundred if I'm buying new (used is a different story) to install selectables if possible. very well worth the extra couple of bucks.

Oh, yeah I never got the cable caught on anything while wheeling. I wheel pretty seriously cutting trails on the farms so I'm always in the brush and rocks. I did forcibly remove the air cyl once, but that was because I hit a deer at 60. after that I build a little skidplate that bolts to the diff cover for some extra protection of the cyl. I've been running this ox since '03 not once ounce of problem once i fixed the cable issue.

[haminawag]

Well my decision has partly been made for me, a guy here in town has a new-in-the-box Ox Locker for the D44, says he bought it at an estate sale, he's asking $100 for it, so Saturday I'll go take a look at it. And if I go with a PT-TC (will have questions about THAT) then I'll probably go with a limited slip rear diff., but not until I make a decision on the TC. Thanks to everyone for their thoughts and advice.
Mike

[will e]

Well my decision has partly been made for me, a guy here in town has a new-in-the-box Ox Locker for the D44, says he bought it at an estate sale, he's asking $100 for it, so Saturday I'll go take a look at it. And if I go with a PT-TC (will have questions about THAT) then I'll probably go with a limited slip rear diff., but not until I make a decision on the TC. Thanks to everyone for their thoughts and advice.
Mike

Wow, that would be a killer deal.

[KJ Ryu]

Even if you don't use it, you should buy it. That's CHEAP!!!

[haminawag]

Wow, that would be a killer deal.

Yeah, that's what I'm thinking, WAY too good a deal I'm afraid. Several months ago I bought a 3/8" thick D44 diff cover for $20 bucks from this same guy and it WAS brand new in the box, old but new, so I'm hoping he'll come through again, that would be very cool indeed, but I'm too old to go getting my hopes up about sh_t like this, my spidey senses are telling me it ain't gonna fly, too good to be true, but I'll hafta wait until Saturday to find out. I'd sure love to go through this guys shop, he had some cool stuff when I was there the last time.

[will e]

My suggestion is you show up with extra cash in your pocket and see what else he would like to liquidate.

[haminawag]

My suggestion is you show up with extra cash in your pocket and see what else he would like to liquidate.

Ha ha, Yessir, he's got a clean 1967 BSA Thunderbolt with the A65IT engine, very much like one I used to ride back in the '70s, but I'm a bit long in the tooth to be riding around on death-mobiles now. It's always a conundrum for me, if I bring extra cash I might spend it, but if I don't bring it I might find something cool I shouldn't spend the $$$ on. Ya know?

[haminawag]

Wow, that would be a killer deal.

Yeah, that's what I'm thinking, WAY too good a deal I'm afraid. Several months ago I bought a 3/8" thick D44 diff cover for $20 bucks from this same guy and it WAS brand new in the box, old but new, so I'm hoping he'll come through again, that would be very cool indeed, but I'm too old to go getting my hopes up about sh_t like this, my spidey senses are telling me it ain't gonna fly, too good to be true, but I'll hafta wait until Saturday to find out. I'd sure love to go through this guys shop, he had some cool stuff when I was there the last time.

Well guys my sixth sense ran true to form, his new-in-the-box D44 Ox Locker was a plastic ice cream bucket full of parts soaking in a half inch of 90 weight, no papers, no way to ID the maker, nothing stamped on it, I walked away. At least he was friendly about it, I was a little pissed since he said, NEW. Oh well, I kinda felt it coming, no big deal.