Positraction Chatter

When looking for great off-road traction an aggressive positraction is one of the most popular ways to go. But, when driving on the street every day that great off-road posi may be annoying.

I have found that it is very difficult to make a positraction work really well off-road and still not chatter during every day driving. Many say that they can do it but my question is can they do it consistently without any customer complaints?

Positraction function has been described well by many before me so I will skip that for now. I use the words “positraction” or “posi” as generic terms for all limited slip differentials (not including lockers).

Posi chatter happens when there is a lot of friction in the clutches. The friction causes the clutches to bind during a turn and twist the axles. Then the clutches let go and the energy stored in the twisted axles is violently released shaking the whole vehicle. It is kind of like a bomb with energy stored in the twisted axle instead of being store in an explosive.

Posi slip happens when there is not enough friction in the clutches and they do not hold when they are needed. Sometimes this can be helped by applying the brake or parking brake lightly in order to add resistance load to the carrier assembly which increases the clutch loading. Even with aid from driving technique a slipping posi is disappointing when off-road and really disappointing when stuck with one wheel still having good traction.

The ultimate positraction would slip during every day driving and then sense that one wheel is slipping a lot relative to the vehicle speed and then apply more friction. Many manufactures have attempted to achieve this through many different types of positractions. Every time I see someone promote the final solution they find a way to upgrade it a year or two later and promote the replacement as the final solution.

For those of you who are really serious about off-road I suggest getting some sort of locker but that can be left for another time.

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