FJ Transfer Case Swap into a V6 4th Gen
Figured I'd copy the first post here of my thread detailing the process of putting an FJ transfer case into a V6 4th gen.
Thread Link:
https://www.toyota-4runner.org/4th-...er-case-swap-into-v6-4th-gen.html#post3605215
--------------------------------------------------------------------------------------
First Post
Reason for Swap
So swapping in an FJ case is always something I had considered but never pulled the trigger on because of how much effort it takes. But, my electronic case just crapped out on me so that has forced my hand.
This swap will be for retaining the factory J-shift pattern on the transfer case and not doing the twin stick mod.
I managed to pick up an FJ Transfer Case from a 2008 automatic FJ for $160 with only 150k miles on it. Luckily this one came with the shifter, cause a lot of the ones I found before did not have the shifter with it.
I have a V6, and most threads for this swap talk about swapping it into a V8, so I'm hoping to create this write-up to help those looking to do this swap in the future.
Why Do This Swap?
The electronic actuator on the factory 4th gen transfer cases tend to leak and not seal properly as they age, allowing dirt/mud/water/etc. to get into the actuator and mess with the electronics and the shifting process. I've always found the electronic shifting system to be rather annoying to deal with sometimes as mine always struggled to go from 2WD to 4HI.
The reason so many people do this swap is to obtain a manually shifting transfer case that has a J-shift pattern (similar to that of a 3rd gen and older Toyotas). The manual shift bypasses a lot of the complicated electronics.
What Do I Need?
I'll update this list as I get farther into the swap, but this is what I know of so far:
- FJ Transfer Case from an FJ with the automatic transmission
- Longer Rear Driveshaft
- Shorter Front Driveshaft
- Wiring harness to connect with the ADD actuator on the front diff
- Shift boot (if applicable)
- Shift knob (if applicable)
Driveshafts
The FJ case is shorter than the electronic case that comes with the 4Runners, so you'll need to do something with driveshafts to make up this difference. Here's a picture of the two cases next to each other for comparison. FJ case is on top and the 4Runner case is on the bottom:
After taking some rough measurements, I found that the rear driveshaft would need to be 1.25" longer and the front driveshaft would need to be 1" shorter.
My current plan for the rear driveshaft is to use a 1.25" driveshaft spacer from 4Crawler Offroad. This can be installed on either the transfer case flange or the rear diff flange.
Here's the link to the spacer:
4Crawler Offroad Products - Driveshaft Spacers for Toyota, Ford, Dodge & Chevy Vehicles
For the front driveshaft, I'm hoping to take some grease out of the slip to allow it to compress more. If that doesn't work, I'll likely cut the splines on the driveshaft alittle shorter. Haven't thought about that too much yet.
Wiring
To get the wiring to work, there's two main things you'll need to do.
1. Wire up the ADD actuator to a momentary switch to get the ADD to work. If you just slap the transfer case in and put it in 4WD, that will just make the front driveshaft spin. You have to engage the ADD actuator on the front diff to actually deliver power to the CV axles.
To do this, take the plug on the ADD actuator and wire it up to a DTPT switch (momentary switch), 12v power, and ground. This will allow you to flip a switch to engage/disengage the ADD actuator.
My current plan for this is to purchase a wiring harness with switch from a fellow 4Runner guy in NC. Rock Solid Toys does technically still sell them, but a lot of people haven't received parts from them and have been waiting for months. RST sounds like the next Pelfreybilt situation, so avoid ordering parts for now from them if you can.
2. The other half of the wiring involves connecting the transfer case position sensors to the 4wd dash lights. Personally I don't care to have these lights work that much since I'll know what gear I'm in with the manual shift knob, so I'll likely just remove those lights from the dash.
Rock Solid Toys has a pretty good and detailed write-up for all of this wiring for a 2nd gen Tacoma which should be very similar to the 4th gen:
05 + Tacoma IFS T case swap wiring instructions
Other
Outside of driveshafts and wiring, the only thing left to do is cut a hole in the floor for the shift knob to come into the cab, seal that up, throw a boot on it and you're ready to go.
This part has some more specific details involved that I will add to this thread when I get there. Happy wheeling!
