RE: Re: RE: locker conversation
I'd like to add a little more information on how Detroits work. I've got a lot of off-roading experience in heavy 4 wheeled vehicles and have had opportunity to observe, use and wrench on them in all kinds of configurations. Germaine to this discussion, I've got a lot of experience with the following types of differentials:
Open - What the M35 has stock
Spooled - Both sides turn at the same speed no matter what
Limited Slip - Clutch packs, work best when the traction difference between sides is "limited", not extreme
Torsen - Torque sensing, extreme differences in traction can be compensated for with brake pressure, essentially turning it into a spooled differential on demand, and a limited slip at all other times (but with no clutch packs to wear out)
Selectable (ARB, Eaton, etc) - open differential normally, when engaged it functions like a spooled differential
Detroit - Output must meet or EXCEED the input
More on the Detroit, since that's the topic here...note how I said "exceed". What that means is the following:
When applying drive power to the input of the differential, it will cause both output flanges to turn as if locked, HOWEVER, both output flanges can turn FASTER than the input is driving them. For example, if you are turning and applying power, the inside wheel will be forced to turn at the minimum speed allowed by the input. The outside wheel will be pushed faster because it is on the outside arc of the turning vehicle. The detroit locker allows this wheel to turn faster than it is trying to drive it via, essentially, a ratcheting mechanism.
When applying braking power to the input of the differential (like when using engine braking), the differential will cause both output flanges to turn as if locked, HOWEVER, both output flanges can turn SLOWER than the input is driving them. In the same turn as described above, the outside wheel will now be receiving the braking power from the input and the inside wheel will be allowed to spin slower since it is on the inside arc of the turning vehicle.
This is why you often hear people complain about a truck with a Detroit locker being loose in the rear in turns. If you enter a turn under acceleration and then let off of the gas during the turn, the vehicle is forced to slow suddenly (due to the transfer of power/slip between the left and right outputs on the differential) and the entire weight of the vehicle will shift as a result. At higher speeds this can brake traction on the axle(s) with a detroit locker, especially on a low traction surface (snow, wet pavement, etc).
Driving a vehicle with a detroit locker on pavement is no big deal, you just need a little more forethought and understanding of the dynamics involved. Detroits in the front are definitely doable, you just have to be aware of the dynamics of how your truck will react to different actions on different surfaces and different turning scenarios.
In my opinion, Torsen and Detroit differentials are the two best options out there for a truck that will be used both on and off road. I don't generally like to modify a vehicle from stock (I'd rather buy it purpose built), but if I were to change differentials on an M35, I would go to Detroits before I went to anything else.
KISS. ARB's require air, Eatons and others require cables or electrical connections. Detroits are rock solid and proven.
Regardless of opinions on which differential is better, the fact is that a truck with a Detroit locker in the front WILL turn just fine. Just be aware of the dynamics involved when going between power vs no power. It could make for some hairy moments if you're not prepared for it. It WILL turn, maybe just not at the exact point you expected it to if you change between powered and not powered during the turn.
Just my two cents.
