Transfer case actuator motor

[vince59it]

Originally Posted by JCL

Hmmm.

I suppose it makes some sense, but I would go back to why it is failing. It feels like it is addressing a symptom, instead of the root problem.

If in fact the gear is inherently weak, then I think we would see a lot more failures of these actuators. If the gear strips, it can function like a type of fusible link. Making it stronger may just move the failure point along to the electric motor.

What the actuator is doing is applying pressure to the clutch packs to vary torque output. If it strips, either it is too weak, or the torque is too strong. My gut reaction is that perhaps it is trying too hard to apply pressure, ie the normal pressure isn't sufficient and so it pushes harder, and strips the gear. If that is true, I would be more concerned about why the pressure is not sufficient. Additional pressure would be required if the clutch packs weren't initialized to the controller (which is part of the servicing procedure) or if the clutch plate friction was out of spec (which could be caused by fluid being out of spec, or the adaptations not set correctly). All of those very possible mechanical problems could cause a stripped gear. So when I hear about a stripped gear, I think more about those likely causes, than whether or not a stronger gear is the solution.

That doesn't tell you what to do about a stripped gear, I just don't know. But it does give some background to potential causes for it being stripped, none of which would be solved by replacing it with a bronze gear.

Basically we have the same approach as I would primarily investigate for the reason of the damage, but so far it seems someone had the bronze gear installed but no feedback.
I have been told that the problem is probably due to the fac that during the "set" cycle (when the engine is switched off,the actuator makes one full run open/close with the clutch in order to reset its values) it is required 1/4 of the full power thus forcing the gear.
I do also agree with the idea of the plastic gear being a kind of "fuse" (the idea is already in my marine outboard engine propeller) but it does not make any sense when BMW asks to pay the full transfer case when the fuse blows (crazy way, isn't it? with a very very high cost.
Do you know anything bout the major fault of TC. I mean, is there any evidence that the stripped gear is the main problem?
Regards from Italy