I'm in the process of purchasing a 94 FJZ with a center differential lock but no front or rear lockers. I understand front and rear lockers but I'm not entirely clear on what the center differential lock accomplishes. I assume that if the front and rear were locked the center lock would lock all 4 together but with front and rear unlocked I'm not sure what's it's advantage is. Is it that it always provides power to either front or rear axle even if one has lost traction, whereas without it, loss of traction on one axle can result in loss of traction on both?
Mmmkay.
Think of a single axle. When turning, the outside tire has to turn faster the inside tire right? Hence why we have a differential instead of a live axle.
Now the 80 is full-time 4wheel drive, so the front axle is always engaged and power is sent to both axles from the t-case. Well, again in turning situations, you now have 4 different tires turning 4 different speeds. The axle differential can balance the two parts of tires but what balances in the middle... the center differential does. Lock all three and you truly have equal distribution to all 4 wheels.
Clear as mud?
... I don't know why but I don't have a clear understanding of the advantage of locking the center differential when both axles are unlocked. Is that with the axles and differential unlocked losing traction on one wheel will cause all traction to be lost whereas with the center differential locked, and the axles unlocked, you would have to lose traction on one front and back wheel together to lose all traction?
Yes, theoretically with an open center differential and two open axles, one tire could break lose while the other 3 are stagnant. Lock the center diff and each axle will have one moving.
Not in a 93+. The viscous coupler will provide power differentiation to the front and rear regardless. In the 91-92 there is no viscous coupler, so all the power will go to the slipping tire unless the CDL is engaged.
......He took the recommendation of a small service station in Moab to pull the shaft and drive home...
Too bad they didn't tell him the rest of the "fix" for driving a 93+ without a dash switch for CDL when you pull a drive shaft. Put it in 4LO, after the ABS and CDL lights come on, pull the CDL fuse and put the shifter back in 4HI. You won't have ABS, but you can drive a very long time on one shaft that way..........
Dave
Too bad they didn't tell him the rest of the "fix" for driving a 93+ without a dash switch for CDL when you pull a drive shaft. Put it in 4LO, after the ABS and CDL lights come on, pull the CDL fuse and put the shifter back in 4HI. You won't have ABS, but you can drive a very long time on one shaft that way..........
Dave