How to: Deleting ADD system

Think I finally got it straight and to the right depth. Such a narrow range of acceptable depth. 4/100ths of an inch. It’s not exactly easy to measure consistently either since the seal face is rubber and gives a bit when measuring against it. Oh well, should be fine.

 

Swapped mine yesterday in a 3rd gen. Took a few hours, around 3.5 working pretty slowly and taking a while to refill the fluid (a pain).

Overall not too bad, just not a fan of working under the front of IFS trucks. Kind of cluttered and not much room to breathe. Anyways, things are working great now. I kept the electronic shift case, for now at least. I may swap it eventually but I don’t really dislike the electronic case. I dislike the ADD much more. I just don’t think the ADD is a great thing to have, in theory or in practice. I don’t care about negligible loss of mpg or added “wear.” The parts spin but at no load and they are lubricated, so I really don’t think there is even a wear argument to be had.

 

This is a 2nd gen thread and I don’t want to hijack that with 3rd gen specific stuff, so I will just mention some info once so it’s out there. I can elaborate more in PM if interested, or a 3rd gen thread could be created.

For what it’s worth, I have been testing solutions for 3rd gens and I have learned that the ADD can be spoofed with one SPDT (5-pin NC/NO) relay. The transfer case can be spoofed with five SPDT relays. All in all, 6 relays to keep everything happy if deleting the ADD and installing a manual case.

I deleted the ADD yesterday and have been running a delete harness for over a week leading up to the physical swap (the harness meant I was limited to 2WD for testing all week). Works great. I hacked up an old 2Lo harness since it had the connections I needed and just repurposed the wiring for what I was doing. Leaving old actuators hanging out plugged in is not my style, so I wanted to figure out any alternative I could to make it work.

I just did this on mine. As I mentioned above, a pretty simple wiring trick using a purchased harness repurposed for the task will make the truck happy with the new change.

 

After soldering the ADD actuator pins it has never ever given me any more problems.

I would only ever delete ADD if I also went with a manual t-case to delete all the electronics from the 4WD system. Perhaps eventually… I see very little good reason to do only one but not the other, but to each their own I guess

 

I can see all sides. Many people would rather leave it alone and most won’t have problems. I’d rather have as active of a system as possible.

2nd gen is nice since you can just delete both actuators and wire the manual t-case switches to the dash. Unfortunately a 3rd gen is going to need its ECU no matter what and will need to be fooled regardless, so I can see more reason to delete one component separately since the ECU is staying no matter what.

I wanted to delete my ADD just to get it done. It’s in the plans to do something with the tcase eventually, but for now electronic case is fine for me. I have a few tcase options that all require work that I haven’t decided if I want to proceed with or not. I could do a manual part time case and keep it stock, I could do a a manual part time and twin stick it, or I could do a manual full time. The full time is what I really want, but I’m worried about getting new driveshafts made and having vibes. Also shifter clearance, and clearancing the shift rods to the transmission are all considerations. Regardless, my front diff is ready for whatever I decide, so I’m happy with it.

 

Guess i have to delete my ADD. Just tried to go into 4lo, and my lights were flashing and beeping. Guessing my actuator is dead from non use

 

Turn that frown upside down. You're more better off without it.

 

Were you in neutral? Fully stopped? Was your four high engage completely first?

 

Yes to all. Good thing Ive got a fj tcase on hand. Just need to do the anytime locker mod first, then I can swap the tcase

i realized i should have posted this in the fj case thread

 

Got a tiny bit of driveline vibe at high speeds (80+) now that the front shaft is spinning all the time. It’s pretty minor but definitely there. Not surprised, the 5.29s are spinning things pretty good. Removed the front shaft and vibes are gone, so I know where my problem is.

Did some digging, calculating critical speed, etc. The Tacoma shafts are 2” X 0.12” and while I’m not quite at the critical speed, there could be a lack of balance or maybe the material starting to give a bit.

I learned that the driveshaft on all 07-14 FJ Cruisers and all non-limited 4Runners 2010+ are basically the same length as Tacoma (0.2” longer), and have a thicker 2.5” tube. They are probably designed to endure more rpm/load. Since the length is so close, I ordered one I’m going to try from the dealer. We’ll see if it solves my problems. Hopefully so.

 

Curious to see your findings on this.

 

Likewise

 

I’ll be posting updates once I receive it. Headed out of town so hopefully it arrives around the time I get back early next week and then I can see how it goes.

 

Just bought a GX470 front diff and tube. I only need the tube. Is the front diff the same for FJC/4Runner/GX470/Tacoma?

If so, Ive got one for sale - $175+shipping obo

 

Where did you get the plug for the truck side of the electrics?

 

You mean in the cab for fooling the ECU? If so, I have a 3rd gen which wouldn’t apply. If you mean the plug for capping the ADD jumper harness connector shown in the pic, that is

https://www.corsa-technic.com/item.php?item_id=1261

and (8) https://www.corsa-technic.com/item.php?item_id=841

need to zip tie the harness afterwards so it
Doesn’t fall down on the CV. In stock form, the harness is mounted to a bracket bolted to the ADD diff tube. The FJ tube has no wiring and so it has nowhere to bolt the bracket that supports the wiring.

 

what you linked is what I was looking for. Thank you!

Regarding cab side, Im going to do the FJ case soon. First I need to do the anytime locker mod.

 

Are you sure? I heard somewhere that the cv axle spline count is different.

@6 gearT444E

EDIT: disregard. The answer is yes. Spline count should be 30

 

Haven't tested the splines yet, but FJ tube acquired! Just needs a little cleanup.

Also, front diff for sale! $250 picked up in Northern VA, or meet halfway for surrounding states up to 200 miles away. Should fit v8 4runner, 2nd/3rd gen taco, manual FJC, Trail/OR 5th gen 4runner, and GX470s

 

Driveshaft finally shipped yesterday, should have it Sunday. Fingers crossed it solves the issue.