It looks like JEGS has TrueTrac's - but I don't know what rear axle you have... .
http://www.jegs.com/i/Detroit-Locker/357/915A567/10002/-1?parentProductId=1032953
"... The install on the power trax is super easy, jsut pull the side and spider gears and replace with the locker, no shims... . "
... . By the way this is a 5900 pound truck with a 350 horsepower early Hemi so it did get a workout.
I suggest you use a ARB air locker if they are available for your diff. It works as an open diff on road and a fully locked diff when activated. It is the best of both worlds, considering the type of roads you have , especially in winter. Mostly you need the locker at very slow speeds and it isn't needed going down the road.
Install requires complete change out of carrier(you will have to move your ring gear to ARB unit and install new carrier bearings) This requires someone with experience at setting backlash, but pinion does not need to be touched if bearings are good.
They are very hard to find. Especially when you are looking for particular options. I took me years to locate the rear I was looking for. Dana 80, srw, disk brake, 4. 10s. It was like looking for a purple unicorn with two tails. It will soon be in. The stock powerloc limited slip is an excellent diff. I believe rebuild kits are readily available again. Unless you are doing serious off roading, the stock unit is very good. One of the best. You cannot deny the superior traction of a true locker, but it comes at a cost of drivability. I have never towed with a detroit, so I cannot comment. The ARB seems to be an awesome choice for thoughs who want to do it all. Open when driving around town, locked at a touch of a button. But WOW $$$$$. I believe the OX and electric lockers are only available for the Dana 60. I could be wrong though. Please keep us posted.