Transfer Case Tuneup and Fix (2 Viewers)

[2021 LC200]

Some folks have been able to R&R these motors. Some have found they're in bad shape and need to replace the whole actuator. The beginning of this thread shows how to pull the external motors off and clean them up.

Actuating 4Lo and the CDL can help, but for slightly different reasons than some people think. It has nothing to do with the transfer case internals engaging or the diff fluid... engaging the mechanisms causes the externally mounted motor to spin which pushes the rod into the transfer case to engage it. There are metal contacts and switches and the activation can essentially help "remove" very minor corrosion - particularly the semi-circle metal contacts.

Nobody is 100% sure why we get the fast flashing CDL light, but because it happens instantly at startup I highly suspect it's because something inside the motor isn't making good contact (or is making contact where it shouldn't, or simply is seeing the motor in an invalid position) and the flashing CDL is the systems way to deactivating the motor to avoid damage. It's always been odd to me that driving for about 5 minutes and then restarting the truck seems to clear it for most people as the external motor isn't being exercised or lubricated like the internal transfer case components. Maybe it's a bit of heat coming off the exhaust or warmth from the transfer case or warm air flowing out the breather that makes things function?

You can also see the above "fast flash" issue if you push the CDL button, particularly when the vehicle is cold. If the CDL flashes slowly that means it's trying to engage and in that case driving and/or turning a bit will usually cause it to lock in as the CDL doesn't want to lock unless the front and rear shafts are spinning at the same speed (50/50). It's why finding a gravel parking lot and doing figure 8's will help - if there's a bit of binding, which could even be because your front and rear tires are slightly differently sized due to wear, then your transfer case might be splitting power 49/51 and so turning slightly will alter the ratio just enough to engage.

Linuxgod, I see the same from reading up on this and watching the online videos. Makes sense after driving and heat and/or vibration and alternator voltage on the system (~14.5 vs 12.5 battery) that things can clear.

Some things to consider as part of longterm maintenance:
- Checking and as required replacing the TC vent line to prevent water ingress, key for the transfer case internals and possible prevention of water ingress into the actuator (having to pass the seal which during actuation seems possible by low viscosity (1cP) water). This is where TC oil replacement can also be your friend. The Ravenol package for LC200 Diffs and TC is not that expensive so that is one good route so it seems.
- Opening up the actuator at say 100k intervals and reapplying dielectric grease. When doing lots of water crossings potentially at shorter intervals.

Is this really needed? Maybe not when all keeps working right. Would it be worth doing when you do not mind wrenching a bit? I would think so.

 

[linuxgod]

Linuxgod, I see the same from reading up on this and watching the online videos. Makes sense after driving and heat and/or vibration and alternator voltage on the system (~14.5 vs 12.5 battery) that things can clear.

Some things to consider as part of longterm maintenance:
- Checking and as required replacing the TC vent line to prevent water ingress, key for the transfer case internals and possible prevention of water ingress into the actuator (having to pass the seal which during actuation seems possible by low viscosity (1cP) water). This is where TC oil replacement can also be your friend. The Ravenol package for LC200 Diffs and TC is not that expensive so that is one good route so it seems.
- Opening up the actuator at say 100k intervals and reapplying dielectric grease. When doing lots of water crossings potentially at shorter intervals.

Is this really needed? Maybe not when all keeps working right. Would it be worth doing when you do not mind wrenching a bit? I would think so.

Mine didn’t have any signs of moisture or any visible corrosion, FWIW