Transfer Case Tuneup and Fix (11 Viewers)

[BrennMan]

What an extremely helpful thread!

Slight anecdote for my specific scenario incase anyone encounters the same thing. I had been having the typical flashing lights that everybody reports and slow engagement. I started engaging the diff lock and 4lo daily to hopefully get everything smoothed out and working better.
All worked as it should for a few weeks and suddenly the 4lo stopped engaging. No issue with center diff. No lights or sounds of struggle with 4lo just no response. Very frustrating.
Followed every ounce of advice in this thread and tore into the actuators multiple times (many thanks everyone!) and couldn’t make any progress.
Finally realized the 4hi/4lo selector knob on the dash had cracked and wasn’t actually turning the switch. Turned the switch with a pair of pliers and *bam* engaged.

 

[Artie]

How quickly should the CDL engage? Mine is sort of all over the place…. Sometimes instant other times 10-30 seconds. There’s no consistency and it doesn’t matter if I’m moving or not or in 4H or 4L. It’s a ‘21 but probably wasn’t engaged for the 1st year after it was built.

I’ll engage it a couple times every time I get on dirt just to use it some weather I need it or not.

 

[linuxgod]

How quickly should the CDL engage? Mine is sort of all over the place…. Sometimes instant other times 10-30 seconds. There’s no consistency and it doesn’t matter if I’m moving or not or in 4H or 4L. It’s a ‘21 but probably wasn’t engaged for the 1st year after it was built.

I’ll engage it a couple times every time I get on dirt just to use it some weather I need it or not.

Mine takes maybe 2-3 seconds if I haven't used it in a while. After that it'll engage within a second. You can hear a relay under the dash click when it is successful (on or off). If yours is slow it could be the actuator motor.

 

[Artie]

Mine takes maybe 2-3 seconds if I haven't used it in a while. After that it'll engage within a second. You can hear a relay under the dash click when it is successful (on or off). If yours is slow it could be the actuator motor.

I’ll take it up to some gravel or dirt this week and do some proper testing on it. I tried to engaged the CDL last week while in 4L sitting at a dead stop, it just blinked for 10 seconds or so until I turned it off and chose the rear locker instead. I had to pull someone out of some mud and was on questionable terrain myself. I should have engaged it again after the recovery just to get it moving but didn’t.

 

[linuxgod]

I’ll take it up to some gravel or dirt this week and do some proper testing on it. I tried to engaged the CDL last week while in 4L sitting at a dead stop, it just blinked for 10 seconds or so until I turned it off and chose the rear locker instead. I had to pull someone out of some mud and was on questionable terrain myself. I should have engaged it again after the recovery just to get it moving but didn’t.

That's not unheard of, if the mechanism isn't perfectly aligned you may have to drive a little bit to get it to engage... hence why doing turns and driving on loose gravel can all help.

 

[Omsok]

I got my little bearing and the tiny $57 tub of grease, assembled the motor assembiles and put it all back together. HURRAH,,, everything works, no christmas tree. Lucky me , now off to fix other stuff. Mitch

Did you cannibalize a new actuator? DO you have an electric motor available?

 

[cruiseroutfit]

For the record, AISIN PN for the actuator is SAT015

It depends on the month/year/market, there are a handful of different 200/570 offerings for the same part from Toyota and thus AISIN

 

[linuxgod]

Re-reading the thread as I've been having issues with my CDL flashing pretty much every morning recently. Thinking I'm going to have to finally bite the bullet and disassemble the motors and clean them. I'm hoping they aren't so corroded that they're unrecoverable

Interestingly when re-reading the thread I noticed the info below. I'm trying to find out at what temperature the sensor operates. The FSM says pins 5-to-27 on the 4WD ECU should show between 0 and 5V. I'm assuming that when the temp sensor closes it reads 5V and when it opens it reads 0V. Beyond that I'm not sure what's happening when it closes as the FSM shows all voltages measured are typically 11-14V, so it's not like the system is kicking up to 24V or something. It does make me suspicious that this sensor is why many of us only see issues when it gets cold though

 

[TeCKis300]

Re-reading the thread as I've been having issues with my CDL flashing pretty much every morning recently. Thinking I'm going to have to finally bite the bullet and disassemble the motors and clean them. I'm hoping they aren't so corroded that they're unrecoverable

Interestingly when re-reading the thread I noticed the info below. I'm trying to find out at what temperature the sensor operates. The FSM says pins 5-to-27 on the 4WD ECU should show between 0 and 5V. I'm assuming that when the temp sensor closes it reads 5V and when it opens it reads 0V. Beyond that I'm not sure what's happening when it closes as the FSM shows all voltages measured are typically 11-14V, so it's not like the system is kicking up to 24V or something. It does make me suspicious that this sensor is why many of us only see issues when it gets cold though

View attachment 3319461

I don't believe it's related to this compensating logic. At some point regardless of compensation, it cannot deliver enough current because of contact corrosion. The fault is temperature sensitive, and battery voltage sensitive, because the switches in the system are electromechanical. Wear and corrosion creates resistance making them more sensitive to these factors. Then the faults can occur even before actuation which is why I'm suggesting this.

From what I've seen, it's the wiper switches switch leading to further wear of the motor brush commutators. There's also a microswitch that corrodes then reporting false actuator position.

 

[linuxgod]

I don't believe it's related to this compensating logic. At some point regardless of compensation, it cannot deliver enough current because of contact corrosion. The fault is temperature sensitive, and battery voltage sensitive, because the switches in the system are electromechanical. Wear and corrosion creates resistance making them more sensitive to these factors. Then the faults can occur even before actuation which is why I'm suggesting this.

From what I've seen, it's the wiper switches switch leading to further wear of the motor brush commutators. There's also a microswitch that corrodes then reporting false actuator position.

Certainly could be, it's just very strange that it never ever happens for me above ~55-60F. TBH I'm just hoping for an easy fix... i.e. "just apply 5V across these 2 leads and it always steps up the motor voltage as if it's cold out and so the issues that happen when it's cool out but not cold enough to normally warrant the extra kick when the sensor closes no longer apply".

Really I'm just avoiding the effort to crawl around on my back and do this. I have skids to install so now that it's warming up a bit I'm going to end up doing it when I pull the factory transfer case skid off.

 

[TeCKis300]

Certainly could be, it's just very strange that it never ever happens for me above ~55-60F. TBH I'm just hoping for an easy fix... i.e. "just apply 5V across these 2 leads and it always steps up the motor voltage as if it's cold out and so the issues that happen when it's cool out but not cold enough to normally warrant the extra kick when the sensor closes no longer apply".

Really I'm just avoiding the effort to crawl around on my back and do this. I have skids to install so now that it's warming up a bit I'm going to end up doing it when I pull the factory transfer case skid off.

When I had the actuator apart, I jumpered the motor directly to a 12V source. The response was sluggish. I don't imagine any compensation logic to provide much boost beyond a direct battery connection.

That's what drove me to clean the motor brushes via electronics cleaners. It woke up the motor dramatically.

 

[isthatalexus]

When I had the actuator apart, I jumpered the motor directly to a 12V source. The response was sluggish. I don't imagine any compensation logic to provide much boost beyond a direct battery connection.

That's what drove me to clean the motor brushes via electronics cleaners. It woke up the motor dramatically.

I've been getting cold-start, but intermittent fail lights again too. Even post surgery, and it's not really that cold where I am. I will pull mine off again soonish and document/report what I find, if I find it.

 

[JohnJB]

I've been getting cold-start, but intermittent fail lights again too. Even post surgery, and it's not really that cold where I am. I will pull mine off again soonish and document/report what I find, if I find it.

So you're not the first person I've heard of who has done the repair only to see the startup issue periodically return. I'd be curious to hear of any more reports of folks who disassembled the actuator and have since had the lights return.

 

[linuxgod]

So you're not the first person I've heard of who has done the repair only to see the startup issue periodically return. I'd be curious to hear of any more reports of folks who disassembled the actuator and have since had the lights return.

TBH I’m tempted to just buy a new actuator and pull off the motors for this reason. I hate doing jobs twice. The only thing stopping me other than a spare $700 is the fact that this is still likely to return after a few years

 

[linuxgod]

I've been getting cold-start, but intermittent fail lights again too. Even post surgery, and it's not really that cold where I am. I will pull mine off again soonish and document/report what I find, if I find it.

Is your breather hose still ok? Any chance the motor isn’t sealing to the housing tightly and is letting in moisture? I’ll be curious what you find as well

 

[JohnJB]

TBH I’m tempted to just buy a new actuator and pull off the motors for this reason. I hate doing jobs twice. The only thing stopping me other than a spare $700 is the fact that this is still likely to return after a few years

I’m in the same boat. I’m fortunate that engagement is quick, it’s just the flashing on startup from time to time. It seemingly comes for a week or two a couple times a year and then disappears with no particular rhyme or reason.

 

[isthatalexus]

Is your breather hose still ok? Any chance the motor isn’t sealing to the housing tightly and is letting in moisture? I’ll be curious what you find as well

I will def check the breather hose, and potentially do the lengthening trick someone on here suggested. Note: I have zero issues with engage/disengage of either CDL or 4L, and 100% of the time does an ignition cycle eliminate the blinking for the day. Of note, however, is that the blinking is not a morning or cold ambient temp thing; it can just as well pop up in the afternoon heat and while in motion. The only hypothesis I have is that something is off with the wheel position sensors, or that the system barfs when I corner too sharply at low speeds, e.g., parking lot maneuvering and sharp turns with articulation as I exit parking lot and get on the road. Who knows, maybe I have to adjust the BP-51 in the rear. A puzzle inside of an enigma.

What I find, I will report.

 

[linuxgod]

Need some RTH guys. I did my 4Lo motor and it worked fine. Did the CDL motor and first time it fired up and no lights, drove a bit and when I’d engage the CDL it would just flash. Took it apart and determined the micro switch wasn’t making contact. Fixed that but reassembled and the CDL light flashes slowly immediately. Pulled it apart again and checked and the actuator rod wasn’t all the way in, probably due to the first attempt. Pushed the actuator rod all the way in, reassembled the gears clocked as shown, but same issue when I start, the CDL light just slowly blinks and the button does nothing. Going to pull it apart one last time before I give up and just have the dealer swap the entire actuator assembly, but hoping someone has an idea why it’s flashing on start without having touched the button

 

[linuxgod]

Update. Micro switch was always making contact. Bent the leads slightly and now that part works ok. No flashing CDL at start. However it’s still not engaging, and I can’t seem to push the actuator rod into the diff, it looks way too far out to me. Anyone have any ideas how to force it back in?!?

 

[linuxgod]

Well after 5 attempts i gave up. If anyone knows WTF might be wrong please let me know. (Paging @bloc, @TeCKis300, et al). The actuator road won’t move in or out, and I don’t know how far is “fully inserted” but I can see all the teeth plus a bit of smooth rod so I’m assuming it’s all the way extended, or close. I tried pushing it in with a bit of leverage as well but didn’t have any luck moving it