Transfer case actuator motor

[JCL]

Ray,my opinion is that what are generally all lumped together as transmission problems (bumping, slamming, etc) can be caused by engine DME issues, by the transmission itself, or by the transfer case. All the systems are integrated, so a problem in any one can cause a hesitation or hard shift that is usually blamed on the transmission. I think that sometimes it is the transmission, just not necessarily always.

If your mechanic is getting transfer case codes, and the actuator is suspect, I would go ahead and change it. I would check the wiring to the actuator closely. I would change the transfer case fluid at the same time, using the OE fluid. I would also reset the transfer case using the BMW computer, after changing the fluid.

Good luck with it, let us know how it turns out.

Jeff

[rayxi]

Just trying to get a handle on what is cause and what is effect. I'd hate to spend >$1k only to address the symptom and not the cause.

Good point about changing the fluid at the same time. Sound advice as usual Jeff, thanks.

[vince59it]

The solution seems to be working as an italian company is producing a bronze gear. But the aspect we are trying to investigate is why this happens? Is this a problem coming from the electronic or is it a problem coming from the plastic gear that is not strong enough? definitely the BMW solves the problem in the easy way...change the TC for about 2000 €!!! and no way to have a replacement gear. Is anyone so kind to post a pic from a stripped gear?
PS: are youtalking about ATC400 or ATC500 TC?

[JCL]

ATC 500 in the X5 E53

ATC 400 in the X3 E83.

Ray has an X5.

[vince59it]

Originally Posted by JCL

ATC 500 in the X5 E53

ATC 400 in the X3 E83.

Ray has an X5.

oK GOT IT!
What is your opinion about replacing the stripped gear with another one made of bronze. Here in Italy we have a company that is doing that.

[JCL]

Originally Posted by vince59it

oK GOT IT!
What is your opinion about replacing the stripped gear with another one made of bronze. Here in Italy we have a company that is doing that.

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.

[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

[rayxi]

Originally Posted by JCL

If in fact the gear is inherently weak, then I think we would see a lot more failures of these actuators.

You also have to consider how many X5's actually need to activate AWD with significant load to the front wheels. Those of you in milder climates never really put much stress on it. We live in the snow belt with frequent melt/freeze cycles and my neighborhood is very hilly. There are times when the 4x4 light is on almost as often as it is off.

It may be a similar situation to the window regulators. Some have replaced 4 or more and some have never had an issue.

[neilrmp]

The problem is the gear, it's made from an inferior plastic, once the motor is replaced the problem is solved, I would imagine if there was another issue with the transfer case the computer in the car would disable the DSC, ABS and 4x4 to protect the actuator from getting damage.. IMO

[vince59it]

I forgot: is anybody willing to post a good pic form a TC gear (a good one and a stripped one)

PS: actuator is the same on ATC400 and 500. Book says only difference is one more clutch disk for the ATC 500.