I think even with the hubs locked, transfer case in 2wd, a front Truetrac will not misbehave because it requires a torque mismatch between the axle shafts, and with the front driveshaft effectively free-spinning there isn't enough torque to lock (again, using loosely) the differential. Maybe someone that has one up front can confirm this but based on the design of the differential I am pretty confident.
That is to say that not only will the truck drive fine with a front Truetrac when in 2wd unlocked hubs, it will also drive fine when in 2wd and hubs locked, which might come in handy if you are doing things where you might need 4x4 (so you lock the hubs), but don't need 4x4 at this moment (so you haven't shifted the transfer case yet).
Outside of the weird scenario in my previous post, driving mine with the tru-trac up front in 2wd but the hubs locked in, you don’t know by feel that it has anything going on up front. On pavement it still steers normally, same on dirt. It does not have the “push” in the front end when turning like an actual locked front axle in 4wd would do.
I’ll even take it a step further if you are in 4wd hi or low range the tru-trac does not make it harder to steer like a locked diff would.
Keep this in mind too. Every limited slip diff of clutch type or helical can fall victim to still sending more power to the wheel with the least traction in a worst case situation. Example being hanging one front tire in the air on an obstacle or one tire on ice and the other on pavement. How “tight” that limited slip is will dictate how much goes to the wheel with traction. If that clutch type version is worn it’s going to behave looser and have more tendency to have the wheel without traction get the majority of the torque. A helical unit like a tru-trac does not have any clutches to wear out. You’ve got 4 helical gears in constant mesh that if you had that one side hanging 2 ft in the air or on ice a simple light drag on the brake (enough to stop the free wheel from turning) is all you need to force more torque to the wheel with traction.
It is a weird feeling to do and a tad harder in practice with a manual transmission like mine has but it totally works. I didn’t even know I could do that until
@AgDieseler told me about it on a trail we were on in Moab. Here I was crossed up hanging my left tire in the air and I wasn’t making any forward progress. Just before I was going to back down and take a different line he reminded me. I drug the brake just a tad with my right foot as I rolled onto the throttle (big feet for the win here) as I let out the clutch with my other foot. It was at that point the truck started climbing up the rock with the right front and the left side settled back down and I drove right on through the rest of the obstacle.
I will admit I have broken front axle shafts with the tru-trac. Which after reviewing the three times I broke one it did have to do with the differential but not in the way most would assume you would break one. Meaning getting to heavy on the loud pedal with a wheel bound up or at full lock on the steering. Which don’t get me wrong you still have a pretty good chance of snapping one if you are on 35” tires or bigger. But in each case of mine i had gotten stuck driving into an obstacle and quickly shifted to reverse to back out of the problem. Each time, one of which I caught indirectly on video that you could hear the snap as it started to move backwards.
Each time I broke an axle shaft I was running the 5.3 with an automatic trans. I’ve yet to break one since I put the 8.1 manual trans in the truck. This is important to note as a change to my process when stuck could have avoided the problem.
When I got stuck with the automatic it was super easy to just take the shifter and shove it from D to R. No pause just jam it in reverse. The reason stuff broke is due to how tight tru-trac is and the fact that I was bound up moving forward. All that torque is twisting in one direction and has taken up the slack of all the lash within all the gears in the drivetrain. The tru-trac holding it all like a wound up spring. Now imagine quickly reversing the direction we have to take up the slack in all the gears from one direction to the other. All that torque now being released in the other direction in a split second. Snap!
Had I taken a moment to pause in neutral before going to reverse the torque/load on the drivetrain would have relaxed and I would have backed up without snapping a shaft. It’s why I’ve not broken a shaft since switching to the manual transmission because to go from a forward gear to reverse I have to push the clutch in and effectively disconnect the driveline and all the bound up torque in the system relaxes.
So it would be the only word of caution I would add to the suggestion of using a tru-trac would be to pause in neutral if you get stuck before changing directions.
