ZR2.com wrote:Eaton Gov-Lo(c)k. It's a hybrid design that incorporates elements from the traditional limited slip (also called a "posi" or "positraction") and a traditional "mechanical locker" (brand names like "Detroit" or "Lock Right").
The way it's supposed to work is that when one wheel slips (spins faster than the other wheel on the axle), clutches in the differential are engaged. The clutches trigger a mechanical system that solidly locks the two axles together, preventing one wheel from spinning faster than the other. The Gov-Lock system will disengage the locking mechanism when torque is no longer applied to the pinion (the part of the rear diff that is connected to the driveshaft).
The Gov-Lok differs from traditional mechanical lockers in a couple of important ways (I'll use a Detroit Locker as an example of a traditional mechanical locker):
Detroits are always locked, they unlock when torque is applied by a wheel being spun faster by the road (i.e. your outside wheel tracking on a turn causes the diff to unlock, and the engine applies power to the inside wheel)
Gov-Loks are always unlocked, and the outside wheel on a turn is the powered wheel
Detroits do not need to sense wheelspin, because they are already locked - they only sense when the road is making a wheel spin faster, and then they unlock (usually with a BANG)
Gov-Loks must sense wheelspin (by the clutch mechanism) and lock when one wheel has gone faster than the other (the threshold for locking is set higher than normally occurs in a turn).
Detroits will instantly cause a vehicle to slide sideways when on an icy side incline
Gov-Loks will let one wheel spin, then engage the locking mechanism, causing the vehicle to slide sideways on an icy side incline (audio imitation: whiiiiirrrrr, BANG, sideways sliiiiiiiide)
Is one better than the other? Not necessarily.
Detroits can cause funny handling characteristics on short wheelbase vehicles (reference the inside wheel being driven on a turn). Gov-Loks have a tendency to engage harshly, causing slides and unexpected wheelspin on both rear tires. Gov-Loks also exhibit a tendency to self-destruct when a lot of torque is applied to the locking mechanism. (Imagine the force of a 31" wheel/tire quickly spinning up to 30 mph and then the locking mechanism trying to engage the other axle/wheel/tire which might be barely moving and on a high-traction surface). The extreme situation like this is when you're 3-wheeling to get over an obstacle.
You can sometimes modulate the locking action of the Gov-Lok by applying the brakes gently when you're spinning a single wheel (this is also a trick you can do with a limited slip differential). It sometimes makes the engagement of the locking mechanism less harsh. My advice is to not floor the gas when you don't have both wheels on similar surfaces -- you'll be less likely to have any of the"bad" locker characteristics bite you in the butt.
Eaton Gov-Lock product brochure info:
-- Submitted By Chuck Conway
