8” IFS Clamshell w/FRS Torsen

Any updates?

 

I’ve been driving the truck as-is for a few weeks now and it’s getting about 18mpg in full-time AWD and Puget Sound traffic. I’m not thrilled with the balance of either driveshaft, so I’ll probably take it to a local shop and see what they can do. I’m getting light, intermittent vibes above 50mph and more intense vibes when I mash the gas to pass above 70mph. It does pass with ease now, traction is awesome.

 

That's awesome, thanks for the update

 

I still haven't figured out if I'm going to use the V8 T4R 4x4 computer or my stock one, but parts are inbound to tie off all the loose ends. I will continue to bury myself in wiring diagrams for a while, but will try to write it all up when I get it working. End result should be all systems functional with triple torsens and A-TRAC.

V8 T4R:
Transfer case wiring harness

FJC:
Brake master cylinder/VSC assembly (good luck finding a used one from a Taco)
A-TRAC switch (in place of currently blank DAC switch)
Main engine room wiring harness

Taco:
VSC Off switch
Yaw rate sensor
RR Diff Lock switch (will be used for center diff)
Brake hard lines from master cylinder
Brake pedal assembly
Brake line clamps

 

From looking at many wiring diagrams and part numbers of different yotes/lexi, I'm pretty sure they all use the same AWD transfer case. The only difference is whether or not you have the ADD up front (and accompanying electronics) or not. I chose to go without, because it's just one more thing to break.

 

No there are a few different transfer cases. Depending on year and trim. For instance the Tacoma case uses 1 shift fork therefore one shift motor. But as far as I know the v6 4th gen 4 runner uses the awd case which has 2 shift forks therefore 2 shift motors. Now a buddy has a 16(iirc) 4runner sr5 and it ls like the Tacoma case with 1 shift fork.

Since your using the v8 4runner case (no 2wd) you might be fine with using your current computer as long as the limit switches and everything are the same ranges as the runner case. The ecu will think it’s in 2wd when actuality it’s in awd. Only consern is will it know how to lock and unlock the center in 4Hi and 4low.

 

I wasn’t saying that all Lexus and Toyota use the same transfer case, I was saying that all the AWD cases are essentially the same, only differences are whether the input is for auto/manual transmission and electronically/manually switched.

The only reasons I’m considering keeping the stock 4x4 computer is to keep the Taco’s factory 4x4 dash switch, compatibility with the gauge cluster, and the ability to turn VSC completely off. From everything I’ve read, you can’t disable VSC in 4WD.

 

Ah, ok. I see what ya mean about the case.

The dash switch should be the same. I’m assuming you compared the wiring diagrams, and they Shound be the same for either computer. As for VSC I have no idea... my truck dosent have it, and if it was me, you could leave that wire disconnected from the tcase ecu if it’s possible?

 

The Taco’s 4x4 dash switch is 2Hi/4Hi/4Lo, but the V8 T4R is only 4Hi/4Lo. I tried the T4R switch in my taco when it was still on the stock transfer case and while it plugs right in, I don’t think it works 100 percent in switching 4Hi/4Lo with the Taco’s 4x4 computer. It also doesn’t plug nicely into the dash hole, so I’d have to do some hacking to get it in there.

I have a LOT of wiring to sort out between the dash switches, VSC, 4x4 computer, and instrument cluster. All I know right now is that I’ve looked at the diagrams long enough to feel like all of this should work.

One thing I know for sure is that the Taco’s DAC switch looks identical to the FJ’s A-TRAC switch and they lead to the same pin on the VSC.

Also, the circuit for the Taco’s rear locker looks very similar to that of the center locker; so ideally I’m envisioning a scenario where I push the RR Diff Lock switch on the dash, the center diff locks, and I get a light on the instrument cluster (if there is one).

 

Man if I weren’t ears deep in my turbo build I’d take time looking into this with you. I’m excited for you and definitely watching this thread. I’d like to see an AWD turbo taco.

 

X2

 

Obviously the next mod for me will be an MP90. No time to tinker on turbo when there’s a fairly efficient, off the shelf boost solution.

 

Which engine do you have?

 

1GR

 

All parts have shipped.

I think I’m going to end up using the V8 T4R 4x4 computer, because the center diff lock switch is to ground and the Tacos RR Diff lock switch is to power.

I have a VSC wiring harness from an FJ and a transfer case wiring harness from a V8 T4R. Time to start splicing

 

I’m loving this thread. If it helps, there was some relevant conversation in this thread from a while back. I have been kicking around the idea of a Quattro taco for a bit too, nice to see others are just as amped about it.

https://www.tacomaworld.com/threads...n-considerations-xpost-from-technical.516067/

 

I didn’t read all the way through that thread, but have you made progress on your Quattro project?

 

Not yet... still in the planning stages

 

started a separate A-TRAC thread here.

 

@JimSnell and more awd action here with info on a gear driven limited slip swap for the front.



@bwawuz02 have you looked into front diff compatibility between the 3rd and 2nd gen Tacomas? I'm 90% sure they're interchangeable and offer more selection of gear ratio possibilities. I haven't been able to compare the 05-15 front diff side by side with the 16+ clamshells.