Should I Replace Transfer Case for $3400?

[BMW_E53]

So today I opened the TC actuator motor to see what the gear looked like before ordering parts and I found that its in relatively good condition. What are your guys' thoughts? I know I didn't take pictures along the gear itself because I didn't want to bombard you all with a ton of photos, but there wasn't any damage or much wear on the teeth like in the youtube videos from other DIYs.

Attached below are the pics of the black gear and the white gear as well. Looks like the white gear is starting to develop a crack so I was planning to purchase the whole Genuine BMW kit from ECS and replace the whole thing. Anybody know a reason why the three lights appeared and then went away?

[14thbmw]

Originally Posted by BMW_E53

So today I opened the TC actuator motor to see what the gear looked like before ordering parts and I found that its in relatively good condition. What are your guys' thoughts? I know I didn't take pictures along the gear itself because I didn't want to bombard you all with a ton of photos, but there wasn't any damage or much wear on the teeth like in the youtube videos from other DIYs.

Attached below are the pics of the black gear and the white gear as well. Looks like the white gear is starting to develop a crack so I was planning to purchase the whole Genuine BMW kit from ECS and replace the whole thing. Anybody know a reason why the three lights appeared and then went away?

There is enough black on your white gear to make me want to look at the gear it mates to - the one in the TC. Mine came out completely white after 165k miles.

The trifecta can come on for a sensor or a transient fault. I get them sometimes when a puddle or spot of ice makes one wheel slip, and it will reset after two minutes with the key out. Or there could be something wrong inside the tc.

[BMW_E53]

Originally Posted by 14thbmw

There is enough black on your white gear to make me want to look at the gear it mates to - the one in the TC. Mine came out completely white after 165k miles.

The trifecta can come on for a sensor or a transient fault. I get them sometimes when a puddle or spot of ice makes one wheel slip, and it will reset after two minutes with the key out. Or there could be something wrong inside the tc.

Here are some pictures of the inner gear on the transfer case itself. My car has just over 126,000 miles.

[14thbmw]

Originally Posted by BMW_E53

Here are some pictures of the inner gear on the transfer case itself. My car has just over 126,000 miles.

That looks pretty clean. Mine didn’t have any grease or dirt on the white gear/spline, and the TC side of yours looks clean too. Certainly no visible damage.

There are much better mechanics/diagnosticians on this forum than I; Pending their replies, since you have a new actuator coming I would put that in and call it good, unless/until the trifecta returns and stays on.

[BMW_E53]

Originally Posted by 14thbmw

That looks pretty clean. Mine didn’t have any grease or dirt on the white gear/spline, and the TC side of yours looks clean too. Certainly no visible damage.

There are much better mechanics/diagnosticians on this forum than I; Pending their replies, since you have a new actuator coming I would put that in and call it good, unless/until the trifecta returns and stays on.

I appreciate your reply and help though! Hopefully after changing the gears and fresh new fluid will help solve the trifecta issue for another 120k miles.

And I see you have a 2018 M5 in your signature......Great choice my friend that car is a BEAST!!!

[cn90]

Original Poster,

The computer calculates wheel rotations, so if they do not match, then Trifecta light.

- Most of the time the plastic gear is stripped from repeated activation of the xDrive on slippery surfaces such as rain or snow.

- Since you live in California, the plastic gear does not have much of a work-out.

- A rare possibility is your electric motor is kaput. I guess you can apply some battery current to the motor to see if it runs. Anyway, the new actuator should answer the question.

[BMW_E53]

Originally Posted by cn90

Original Poster,

The computer calculates wheel rotations, so if they do not match, then Trifecta light.

- Most of the time the plastic gear is stripped from repeated activation of the xDrive on slippery surfaces such as rain or snow.

- Since you live in California, the plastic gear does not have much of a work-out.

- A rare possibility is your electric motor is kaput. I guess you can apply some battery current to the motor to see if it runs. Anyway, the new actuator should answer the question.

Oh that makes a lot of sense now. And I wanted to test the motor but I was unsure which pins control/supply the power. Do you know which pins on the motor supply power so I can test it?

[cn90]

Originally Posted by BMW_E53

...Anybody know a reason why the three lights appeared and then went away?

Classic reason is "low tire pressure".

Let's say the LF tire is 40 psi and the RF tire is 20 psi, you will get the Trifecta lights.
I learned it the hard way, don't ask LOL.