- Joined
- Nov 3, 2003
- Messages
- 48,143
It's not that your old information was completely wrong. It might have been the recommendation for a particular 4wd system (there have always been variations) or it was just someone's misinterpretation of the instructions.
In our case, the Dana 20 t-case is non-syncrhomesh, so you're only supposed to shift into LOW-range at very slow speeds. Into HIGH-range you can shift into 4wd at substantially higher speeds, but should probably still limit that to maybe 45 mph or so. I think 55 mph was the original recommendation, but I'm not sure about that anymore.
And that's just for shifting the transfer case. No limit on the hubs themselves. In fact, if you think about it, most, if not all modern 4wd trucks don't even have lockouts (locking hubs) any more.
Now you have to buy an expensive conversion kit to get 'em!
With our type of t-case, you're getting equal torque to the front and rear through the driveshafts. Without some sort of TAD though, you're never guaranteed to get equal torque to the left and right tires. There are exceptions of course, but one of those is that when both tires are spinning on ice, you probably have equal torque to both sides!
And Early Broncos did have optional limited-slip differentials available from the factory. So you could have some still. What year is yours? Look at the glovebox or kick panel tag to see what axle codes it's got. Or if they're still there, look for the metal tags under a bolt at each differential (front cover, rear housing) to see what it says.
Someone here can interpret them for you, but basically, if you see an "L" in there, it came with a limited-slip originally. No guarantee it's still there of course, or if it is, that it's still fully functional, but it's a good place to start.
Nice feeling eh? You might as well spend some quality time in your Bronco with just you (and any interested parties of course too) tooling around the neighborhood to get a real feel for how it works and feels in 2 and 4 wheel drive.
Can't hurt, and it's fun to play around and find the limits when you're in a safe zone, rather than out on a highway or next to a school zone!
It's a good thing to learn especially the basics. What you're doing with the hubs UNLOCKED is simply spinning the front axles inside each hub. They're doing nothing useful except spinning merrily away inside the differential and hubs.
Once you lock the hubs, you're literally tying the axles to the drive hub assemblies to turn the wheels. Without them being locked, the wheels are free to spin. The only exception to that rule is some models of Automatic Locking Hubs that will self-lock into drive when power is applied to the axles in 4wd. But as soon as you reverse, they can unlock.
Some of those older automatic hubs were not fully locked in until you got out and did it manually.
Sorry to add more stuff that you probably already know, but visualize what's going on by following the path of power. Engine to transmission, then to transfer case that "transfers" power to both ends, then through both driveshafts to the differentials, which turn the torque 90° out the axle shafts to the drive hubs. Without that last little bit of hardware locked up, nothing of any real meaning can happen.
Piece of cake...
Paul
