ADD front diff?

on the 2nd gens, what does it stand for and how exactly does it work? I know its like the opposite of manual locking hubs but I could be wrong? I'm just trying to figure out how that system works, if anyone know anything i would appreciate it, thanks

 

Automatic Differential Disconnect. It is a motor on the second gen, and vacume actuated on the first gen tacomas. It disconnects the passenger side axle so that the differential and driveshaft are not under laod. It leaves the drivers side axle connected to the differential so the spider gears will continue to spin on that side but there is no load on the drivetrain.

If you need more info on what the spider gears are there is a thread that explains how a differential works up above.

 

okay I didnt realize that much stuff was going on. I thought 4wd was only controlled by the transfer case? how can you get around this system if you want to use an fj t case? do you add another switch that would turn on the add?

 

The ADD (automatic disconnecting differential) allows one to shift on-the-fly into and out of 4WD (High). It was on the First Gen Tacos as well... It replaced automatic locking hubs which required driving in reverse to fully unlock.

 

You can create a circuit to control the ADD motor by a switch. If you search into the FJ case swap there are some wiring diagrams to follow. OR.......... you could SAS and have manual hubs.

 

Or fit an FJ cruiser manual case and put in an ADD switch.

 

yeah that's right, that's why I'm looking into this to see if it is even remotely possible to do a 4x4 swap in a second gen prerunner and how hard it would be, which seems like slim and very.

 

yeah but if I SASd my truck it would be the biggest waste of a SAS here on TW just saying

 

snow

 

...or unbolt extension

 

The easiest way to convert your PreRunner into a 4x4 is trade it in for one. You're going to be spending way more trying to convert it than just trading in your PreRunner for a 4x4 and just paying the difference.

 

I would rather not trade in bc of the good deal i got otherwise I would have bought 4x from the start and trading in would be more expensive then doing the swap the other reason for doing the conversion over trade in is having the manual t case from and fj. I have had 3 different occasions where the tacoma t case decided to take a crap at the worst time. SAS would be ideal, but i would never use it to its full potential IFS would get the job done no problem.

 

I'm one of those. 3-4 60 lb bags of tube sand takes care in snow for me for the last 23 years with 2wd trucks in WI, IA and CO.

But I don't ski regularly and don't head to the mountains when snow is in the forecast or I'd find myself needing 4wd soon enough.

 

If I was going to hook up a switch to use the ADD separately what switch would I use. then would it matter putting into 4wd first then switch or the other way around?