Another 4x4 probem... (System won't shift into 4Lo)

This is extremely helpful! Wondering where you found these details? You have to subscribe for a service?

 

Glad to help. It used to be publically posted on the Interweb, but Toyota lawyers sent nasty grams to get it taken down. If I were you and wanted access, I'd Pay a little bit of $$ to have access to the same info Toyota techs do. http://techinfo.toyota.com

 

cool thanks!

 

Is the truck an auto or manual? If it's manual, you may not be depressing the clutch far enough, or the clutch has enough wear it won't allow 4 lo to engage?

 

So you're shifting into 4LO while moving? Unless its changed my manual says to be stopped, and in nuetral before shifting into 4LO. If I try it on the move and at low speed it beeps like crazy and the 4x4 light flashes.

 

Don't start tearing into anything before you verify, with a meter, that a switch is bad. It wastes time, and usually causes other problems!

Don't lie where a tire could roll over you

 

^^you can use an ohms meter you can tell if any switches or accuaters or wiring is bad or has problems without taking anything apart.

 

Have you figured anything out on this?

 

Unfortunately I haven't... I was really hoping it would be the failure of either of the 2 transfer case indicator switches that are located on the transfer case #84222 forward switch and #84222b aft switch (Easy cheap fix). I tested each switch and they show no resistance which means they should be working properly. However, i looped a wire (paper clip trick) to complete the circuit on the the aft selector switches and was able to get the 4hi light to stop blinking but it also illuminated the 4lo light and than would not allow me to operate the 4x4 system at all...

My next guess is the shift motor on the transfer case. Maybe its not actuating all the way since the transfer case seems to be getting electrical. Or maybe there is an issue with the vaccuum system? Starting to think the $105 isnt such a bad price for pinpointing the issue...

 

I had a similar problem. I hadn't used my 4x4 in quite a while. So due to that, I decided to look at the contacts, inside the actuator.

I VERY CAREFULLY removed the plastic cover, taking note of how things were lined up inside. (Basically where the contact pads/finger were with the truck in the 4x2 position)

I ended up finding that there was a lot of carbon or other buildup on the contact strips. I cleaned those off with electrical contact cleaner, and a soft rag. Put it back together, and BAM. Worked like a charm.

I also had to replace a portion of the breather hose on the cover, as it was dry rotted and cracked through.

I hope that helps.

 

thanks dude!

Ill give that a try before i surrender

 

You're welcome. Just be careful taking that cover off. Little gears are in there and need to stay properly aligned. Still a simple check though.

 

In the manual trans going into 4 lo have to be stopped out of gear and clutch to the floor to engage to 4 l id imagine same for autos in neutral. But outside of that. I had the same issue, i crawled under the truck and the connections on the accuator on the transfercase came loose. Clipped them back in with a cleaning and back in buisness

 

X2 on this........the contacts inside the Transfer Case Actuator gets "gummed up" and needs to be cleaned with Electrical Contact cleaner....put i back together and you should be fine. Good Luck

 

Any luck on solving the issue?

 

Well i cleaned inside the transfer case actuator with electrical contact cleaner and no luck. It was pretty clean and there seemed to be plenty of grease on the contactors.

I posted on ih8mud.com the problem and a toyota service guy posted the electrical diagram for the ADD. Referencing the sequence of the 4wd on these trucks he believes its the indicator switch on the ADD.

I have since tested the ADD switch indicator wire and it shows resistance while in 4hi (grounded). If this confirms what the toyota service guy believed my next step will be to take apart the ADD (pain in the ass) and clean the electrical contactors on that actuator. Hopefully this does it... other wise i might just take it to the dealership and have a diagnosis performed because i would hate to replace the ADD without that actually being the problem (since it does engage the 4hi).

 

The FSM calls for removing the front differential in order to remove the actuator.

That's a PITA, with removing and reinstalling the CV axles.

But if you're going to DIY it - you don't need to do all that; you can drain the oil, leave the CV's connected, loosen/remove the bolts holding the differential in place, and let gravity lower it far enough that you have access to remove and reinstall the actuator. Be sure and support the differential with a floor jack.

Make sure you reconnect the two rubber vent tubes - as they will come off when you drop the differential down.

Here's a photo documentary thread:
http://www.fjcruiserforums.com/foru...differential-actuator-repair-replacement.html

 

Yea i found this writeup which is extremely helpful since its way easier than the book instructions. However, I was hoping to just remove the plastic cover that houses the electrical contacts and the motor to clean them before i replace the ADD. Im assuming there is no gear lube in these areas of the ADD is this correct?

Just trying to avoid the drain n refill of the axle if i dont have too...

 

Yes - the electrical connections are sealed off from the actuator arm. You might be able to access that separately.

Be advised there are tiny parts inside that area of the actuator though, and it's not a real easy area to work in. You may find drain-n-refill to be worth it in order to get better access to the electrical parts of actuator on your workbench.

Or not.

 

Well a little good news i guess... The system is now working properly (not sure for how long though).

I posted the same thing on "Ih8mud.com" and a very knowledgeable toyota tech service guy posted the electrical diagram of the ADD and his guess was the indicator switch on the ADD was not relaying back to the ECU that the vehicle was in fact in 4hi (due to the sequence of the 4x4).

So My brother (electrician) tested the indicator switch wire on the ADD with an ohmeter and it was showing significant resistance. Therefore the switch wasn't closing or completing the circuit which is why the light would continually blink eventhough it was in 4x4.

My next plan was to open the actuator and clean the electrical contactors in hopes of it just being a contactor issue that could be cleaned. However, It warmed up out here last week and i washed my truck including the underbody (wash the salt away) and for whatever reason the 4hi light works now (stays on) and i am able to once again engage the 4Lo. Not sure if its because it got warm out or the water did something or it was electrical contactor cleaner i had sprayed a week earlier inside the ADD electrical actuator housing that had finally settled. Either way it works but im sure ill end up replacing the ADD at some point in the near future...

Also, it would have been wise to actively engage the 4x4 actuators every month rather than just the winter season to ensure smooth operation.