I think that would be true of the X drive version as it is infinity variable and works in conjunction with ABS and DSC systems. Earlier transfer cases were mechanical with constant split between front and rear. Could still be true of the mechanical version if only because of the effects of cold weather has on most things, like my fingers and toes.

its nice to know you can just get the gear instead of replacing the whole unit assembly.

Mine lasted 170.000Km (105K Miles) and we have some decent winters over here.

Update: I ordered the gear over the weekend at ECS Tuning and from the tracking number I should be getting it on Thursday ( Very impressed with ECS btw) ...
My X is going to my Indy for oil leak on Friday so I'll have him remove the actuator so that I can replace the gear. I'm still questioning myself on what caused this failure the same day I changed to my winter setup and afraid I'll strip the brand new gear. Hopefully it was only a coincidence.

I'm debating on whether I should flip the old gear and drive with it and see what happens or install the new one and risk it...

:dunno:

I subscribe to--there are no coincidences.

I assume you measured the diameter or circumference of the tires to see if there is a variance of 3% or more?

When the indy read the codes did he clear them so you can see if they all returned?

The change from 20" to 18" wheels can effectively change the gear ratio. That means that at any speed you travel the engine will very likely run at higher RPMs with the 18"wheels. I think that means that anytime the transfer actuator is engaged the gear will be under greater stress than with the 20" wheels. If that is correct and the gear was already worn the change could cause the gear to fail.

The fact that the 4X4 light was on the last time the 18" tires were on means to me that the tires sizes are at part of the problem.

I would do complete any troubleshooting to confirm the cause of the lights and then if I couldn't find a cause other than potentially the gear I would put in the new one.

I would think the smaller wheels and tires would effectively reduce the moment of inertia thus reducing the stress on the system (less rotating mass).
Comparing stock 20" tires vs winter 18", on tire rack, the winter tires are actually 0.3" larger, so drivetrain would actually run slightly slower, not higher.

To answer some questions:

Yes my indy erased all the codes and will read again on Friday when I bring it in but all the light came back on.

Also , I mesured the tread depth of all 4 tires: (pirelli scorpions ice&snow) 255/55R18

Both rear = 10/32
Right front= 9/32
Left front= 8/32

I am fine using your point of view, it doesn't matter.

I don't know if there is additional stress on the gear or how much it would take to strip out the gear if there was. It was just a scenario to suggest how it might not be a coincidence. I don't have enough information to know what is fact.

My guess is mass moment of inertia is insignificant but I don't have enough info to know that for sure either.

The diameter of the tires could be smaller. I don't know because I don't know if OP has snow tires and if he does if they are Tire Rack recommendation. What I would need are the diameters of the summer and winter tires.

The input OP was interested in--should he flip the gear or install the new one?

My summer setup is the usual 20's staggered

and my winter's are 255/55R18 Pirelli Scorpions ice&snow
Mesurments:
Both rear = 10/32
Right front= 9/32
Left front= 8/32
If someone tells me the uneven wear of my front is the cause of all my headache I kid you not, I'M SELLING THE X!!!!! :wahwah:

The tread remaining is not the issue.

What are the diameters of each tire? Lay a straight edge on the top of the tire and measure to the ground passing through the center of the of the wheel.