Yet another 4wd not working....but rear locker works??

Hi all,

I have a 2004 5-speed manual 5MT Tacoma with the J-shift transfer case. I cannot get the 4wd to engage, I don't hear the normal click under the dash when it engages and the 4wd green indicator light doesn't come on the dash when I switch it to 4wd. I do however hear the little electronic click near passenger footwell, indicating maybe the relay is working?

I put it in 4lo and engaged the rear locker, and it engages the rear locker no problem. Confused because if it's not in 4wd how does the rear locker still work? I can hear the lower gears working when in 4lo as well, because it has the typical gear whine when in low.

I just don't think there's any engagement going on with the front diff to the wheels.

I've read countless threads on all the variations of the TC over the different years, and those with vaccuum VSV, those with electric switches, ADD, etc etc etc.

So, I need some help narrowing this thing down. I want to start with the ADD relay in the passenger kick panel because that's easy, but I need to find the right part number for that relay so I can switch it out with a new one. Does anyone know the part number for this? Does the 2004 EVEN HAVE the relay??

And sorry for yet another 4wd not working thread, I've read every thread on this topic but I just wanted to post this to get more specific assistance with my particular situation. Almost all of them had either a j-shift or a push-button and no clear specific route of diagnostics for a J-shift with manual on an 04 (and it's particular differences).

 

The rear locker computer looks for the 4WD selector position switch (similar to the reverse light switch on the manual trans) so if the J shift case is in 4WD low and you're moving less than 5mph the locker sees all it needs to engage independent of the front diff ADD tube engagement.

I know the early first gens were all vacuum actuated but I think the laters had some electronics.

Do you have manual locking hubs?

Has the 4WD worked before?

 

Makes sense on the locker, well, at least that works. It does not have manual locking hubs.

I just bought the truck recently, and the previous owner says it has worked in the past yea. I just dont think he used it much though.

So I thought that:
04 Jshift Buttonless=Electronic ADD actuator= no vacuum from Tcase to front diff. So the only thing controlling front diff to engage are: the actuator it self, and if my 04 has a 4wd relay? Would the relay click if the relay not sending juice to the front actuator? So am I right in thinking those are my two most possible causes (relay or front ADD failing) ?

I do hear a slight click noise in the passenger footwell behind the kick panel when switching to 4wd. So not sure if that means it’s working or not, but I would replace the relay if I knew it’s part number. Seems NLA.

Does the ADD have a switch on it that I could replace?

 

You may have gotten moisture in the ADD actuator through it's vent hose that has corroded the small drive gear, servo motor or electric connection inside.

 

Anyone have a part # handy for the actuator? I guess I'll just go ahead and swap that out.

Would any of these be suggested?
https://www.partsgeek.com/catalog/2004/toyota/tacoma/driveshaft_-ar-_axle/4wd_actuator.html

 

https://www.partsgeek.com/gbproduct...JBrRDOD0Pe4J0C98Q1SjHNCGS8-VAf5xoCHf0QAvD_BwE

 

Check the 4hi switch on Tcase and electrical connection on ADD Actuator before buying new actuator.
If the ADD vent is broken off or hose has been missing replace actuator.

 

Can you help me locate that 4hi switch on T-case? I think theres like 4 switches on the T-case.

 

Ok, I am hoping this is an electrical issue or just an issue with the front actuator. (ADD).

My truck doesnt even have that rear actuator attached to the transfer case thankfully... so I will not have to be opening that can of worms... seems very complicated.

 

Correct on both
Jshift without 4WD button does not have a Tcase actuator.
Start with switches and wiring on Tcase AND ADD Actuator vent broken off or hose disconnected.

 

Before going too far with removing/rebuilding/replacing actuators, etc.. I'd suggest just removing each harness clip in the exterior 4wd system and spraying them with an electric part cleaner first.

 

I'm trying to locate the switches now...are there any in the engine bay on the 04s?

 

I would be more concerned about the clips on the actuators as they are prone to getting wet, etc..

My 4wd was not consistently engaging, and I feared the worst and began looking for a new ADD actuator.. but I pulled all the plugs, cleaned them, put some di-electric grease on them, and everything has been working great since.

 

Thanks... and sorry for the elementary response, but I'm still learning how this 4wd system works. Which plugs are you referring to? Can you please provide me with perhaps a photo so I can begin cleaning them first?

 

3 switches are shown in this pic

Electrical connection (plug) is on end of each switch.
@bmwahba

 

Does anyone have the part number for the 4wd relay in the passenger footwell for the 2004??

I cannot find the part anywhere.
The only thing I can find is this:
89531-35020

Listed as the transmission control relay, and says it does not fit a 2004....

 

Also, can someone please make a definitive post on the part numbers for these switches. I have searched the entire forum and can't find it. I want to order all 3 of them and just replace them all. Does anyone know if all switches are the same part number? I am unsure if this one will work in all 3 or 4 of the switches that are on the TC:

https://parts.lakelandtoyota.com/p/...H--TRANSFER-Indicator/4153906/8422235090.html

Part number:
84222-35090

What a mess....I have never had this much difficulty finding replacement part numbers.

 

Found another.... different part number, this being the "Transfer 4WD Position Switch" and it's part number is 84222-35110.

I'm pretty sure all of these switches are identical...but... if I can find them I will just replace them all.

This diagram does not listed the 8422-35090...... for what I can only seem to see that it is for an Automatic transmission only not manual..





So is it safe to assume they're all basically the same?

 

The switches are the same but some have attached wiring and electrical connection (plug)
84222-35110 is correct 4lo switch.
84222-35090 is correct 4wd position switch.
84222B-35110 A/T neutral position switch.
The transmission control relay module (4WD ECM) is located under passenger side kick panel and the #s are printed on it. 89531-35050 for 2004.
Have you cleaned and lubed ALL switch connections (plugs) and checked Front differential ADD Actuator vent hose for breaks/leaks that would allow moisture inside ???

 

Ok. Update, Got under the truck today. I found this plug on the driver side of the Transfer Case broken, and the connection was likely not being made.

so two questions:
1. How does one even get this threaded switch and plug out? The thread is large maybe 20-24mm… no way I can fit a wrench in there.

2. maybe , just maybe, since I’m having such a hard time replacing the whole plug and switch (with the wiring like mentioned in posts above) is there any luck in perhaps just replacing the plug end itself? Does this plug end exist somewhere online where maybe I can just cut the old plug and wire up the two wires to a new plug that matches the engine wiring harness?

of course, that would mean I am assuming the switch itself is operational, since I wouldn’t be switching the switch end (the end that threads into the transfer case) since I’m having such a hard time removing it without dropping the transmission.