4x4 Issues, Front diff actuator or t-case actuator?

Really easy to diagnose. Put your truck up on the jack stands so all your wheels are off the ground. Shift it into drive and then shift in to 4wd and take a peek under your truck to see what's spinning (front driveshaft and/or BOTH axle shafts). If the front driveshaft isn't spinning it's your t-case actuator. Here's what I did when I found out my front actuator was bad (notice front driveshaft does spin.

http://youtu.be/sZYRJgfVvFM

If it is your 4wd ECU I have one I call sell you for cheap when I did the FJ case conversion.

 

I will also add that I've NEVER heard of an ECU going bad, it's almost always those junk actuators from Toyota.

As stated earlier it may be the 4hi/4lo position switches on the actuator as well, those can simply be unscrewed and measure continuity on the pigtails while pushing in the sensor ball to verify they open and close as expected. Another very very small possibility is the 4wd switch itself on the dash, but once again those rarely fail. 99% of the time it will be the t-case/front diff actuators.

 

Yeah I mean it didn't make a whole lot of sense why it would be the 4x4 ecu especially since I heard the "clunk" right below me. Anyone in the Denver area have time to swap 4x4 ECU's?

Also what happens if the shop is wrong and its not the ECU? Am I out that money or can I have them put the old one back in? the 4x4 ecu is about $400

 

I will sell you mine for $20 + shipping if you want, it works fine. But I am telling you are wasting your time to swap them out.

 

They didn't have one to swap. Said it had to be ordered in and it would be in next week.

Is there any way to to test the sensors to tell if they are bad?

 

Yes. Did you go to a dealership? They would hopefully know enough to follow this procedure-
http://www.customtacos.com/tech.old.../06toyrm/06toypdf/06rmsrc/rm2006ta/034000.pdf

Although these days it's hard to find a good dealership tech. Get yourself a $20 multimeter and follow the procedure man.

 

I often wonder why people ask questions on this site and then don't listen to any advice. Good luck with your $400 ecu that's not broken OP

 

Few things here:
1. The front diff actuator has a known issue with its electrical connection. If you unbolt it and expose the wire terminations you can actually solder the loose connections. This fixes the "blinking 4wd light" issue most of the time.

2. The actuators require maintenance. That is to say you must "use" them to keep them operational. Otherwise you risk them locking up. The manual tells the owners about this requirement to "exercise" the 4wd system.

I was stuck in Death Valley off the side of a trail and had my front diff act lock up. Couldn't pull myself back up on the trail in 2wd. It sucked and luckily had a guy near me to tug me up on the trail.
The soldering of the act fixed it, so well in fact that it now engages into 4wd faster than it did when the truck was new.

There are write ups on this fix if you search.

 

Didn't go to a dealer, they told me it would be 3 weeks before they could get me in so I just went to a local transmission shop.

 

Ha, trust me. I trust more on this site then anything else. I question the ecu quite a bit! I plan on working on the things posted this weekend. I have a friend with a 2007 FJ cruiser, are those 4x4 computers the same? Could I test it with the FJ comp?

 

Fj cruisers have a Manual transfercase with a lever not a computer. That's why Psu offered to sell you his ecu. He'd did the fj transfercase swap so now he doesnt need the computer.

 

Got a bunch of information at this link that may help
http://www.tacomaworld.com/forum/te...ase-transfer-case-2nd-gen-truck-write-up.html

Did anyone mention anything about the TSB http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=174188

 

Alright so got my truck back from the shop today and sure enough wasn't the 4x4 computer. They in fact told me they had no idea what it was and that I should take it to Toyota. Great. So start driving in 2 wheel drive as usual, go to a friends to see if he has any bright ideas. He got under the truck and spun the front drive shaft maybe 3/4 turn while the truck was running and in neutral and the truck went into 4 low. Great! except now it wont come out of 4 low. I have tried everything, forward, reverse, shaking it back n forth. Does any one have any ideas what could have caused this and how to get it back out of 4 low so I can at least drive again?

 

Are you sure it's in 4L and that the front actuator does not just have the front wheels locked. Mine felt like it was in 4wd but just the front was locking up. Jack up the truck and see if the front wheels are actually turning?

 

I mean it wont go over 25 mph and definitely feels like its in 4 low. Did some tight turns and felt the front wheels chatter so I figured it was in 4 low. Haven't jacked it up yet to really tell for sure.

 

hmmm big surprise there

To get it out of 4lo just unbolt the actuator off the t-case and push the shift rail all the way forward. The actuator is the black thing in this picture to the left of the rear output flange.



Sounds like you need a new t-case actuator, they are only around 800 from the dealership

 

So I have taken off that black cap on the t-case actuator and didn't really see anything to push all the way forward. Is there any images with the actuator off so I can make sure I am doing the right thing? As of right now the truck is almost undrivable.

 

Not the cap, that's just the motor. You need to remove the whole actuator off the transfer case, it's three 12mm bolts.

 

I already said that on page one. I can understand ignoring our advice on someone else thread, but we are spoon feeding this dude the answers and he is not smellin' what we're sellin'. You can lead a horse to water...

 

Ha, OK. I do appreciate everyone's advice, but your post was a little misleading. You said remove the 3 10mm bolts, to me that meant the cap since the whole actuator is held on by 3 12mm bolts and in order to get that out you have to remove the cap as well. I just wanted to make sure I was doing the correct thing to get it out of 4 wheel drive, so I asked again. PSU Taco85, thank you for the correct info, got the truck out of 4 wheel drive this morning.