Transfer case swap. Multi mode 2WD AWD VF3AM + VF4AM

Any update?? So you’re using the VF4AM but are you going to make it manually shifted or keep the dual and motor? Are you going with an add front diff?

 

No updates, but hopefully life allows some serious gains to happen this spring/summer.

The t case will probably be a combination of manual stick for H N L and one motor for 2WD/AWD/4WD. I’d like to have all manual, but keeping the electronics happy will require splitting it.

The diff ADD actuator will need to remain to keep the ecu happy. I’m undecided if it will remain and have the physical moving shift fork disabled (just the motor running to trip the sensor), or keep it as part of system. It will probably depend on what diff I run up front.

 

How are you going about converting the the HNL electronics to manual? i wish it were as easy as just welding heim joints to the front of the shift rails and hooking them up with rod linkage or cables. .

As far as the ADD goes, if you ran a VF4B, could you just use the ADD to dis engage the front diff to be able to get 2wd instead of Awd? Then by toggling ADD on and off you are switching between 2wd and AWD/ 4hi. Does it work like that?

 

I’ll have to swap the rail and fork from a manual case. The truck will probably always think it is in high range, though I could add the detection switch, I suspect (may have read this) the ecu won’t accept the signal w/o first running the motor to initiate the shift.

The add will be required if I run the motor shift for 2WD AWD 4WD. The dial on the dash will give 2wd = 2wd, 4WD = AWD, 4L = center diff lock.

 

I get this, I guess I’m trying to figure out if you could run the VF4B in awd with the ADD off to mimic 2wd.

 

Too late now, but I would have called Marlin Crawler on this mod.

 

So after I’ve spent all day on this, I’ve now decided that I’m after a multi node case from a 99-00 limited 4runner. It’s a vf3am with a jshift for 2wd/awd, 4hL, 4LL.

 

I’ve gone pretty far down this same rabbit hole to get 2wd/awd/4hi/4lo modes on an 06 tundra drivetrain so following along on this thread and going to chip in the info I’ve learned.

I’m planning to stay all electronic and use the v6 4Runner 4wd ecu and the rotating style switch, but the 05-07 sequoia transfer case.

the difference I’ve found between the 4Runner transfer case and the sequoia is that the sequoia has a VSS sensor whereas the 4Runner has no vss and uses the abs computer for speed signal. The electronics of the shifting look to be the same. It may also be built for the higher torque but not sure.

I’m swapping the tundra drivetrain with the swapped transfercase into a Volvo 940 off-road/rally build which is weird, I admit, so the direct vss helps simplify things for the swap.

 

Did this swap ever get completed?

I have a 3rd gen 4Runner w/ multi mode (VF3AM) t-case and I love the “AWD” mode it offers. Great for icy or slick road conditions where shifting in and out of part time 4wd would be a true PITA.

@Jowett, instead of wiring up the the dial so that 4H puts it in AWD, and 4L locks center diff and puts it into part time 4wd. Have you considered adding a push button center diff locker switch pictured? You could have the push button put the t-case into AWD mode, and then the dial to put it into part time 4wd and 4Lo.

 

Another user finished a multimode swap, over here:

https://www.tacomaworld.com/threads...wapping-in-the-3rd-gen-4runner-t-case.794828/

 

Good read, but that’s a 1st gen Tacoma getting a 3rd gen 4Runner VF3AM t-case. I’m more interested in the VF4AM t-case from the 4th gen 4Runner going into the 3rd gen Tacoma.

 

Whoops, totally overlooked that this is in the 3rd gen section. Carry on...

 

@Jowett, question I have is how would you integrate the VF4AM’s 4wd ECU into the 3rd gen Tacoma CAN bus? I know very little about CAN bus, but it seems like that problem would need to be solved, if nothing else, to get the 4wd indicator lights on the dash to work.
The snippet below is from the ‘16 -‘23 Tacoma EWD, and shows its 4wd ECU hooked into the CAN system.

 

Thanks for keeping after me here. My Tacoma project is paused at the moment, so I have not gone any further. I’ll need to look into the CAN connection and a way to deal with it.

 

Does the VF4AM ECU use canbus at all? If not, then you could run both ECUs. The stock Tacoma ECU can be fooled with relays, so if you use a knob or switch or something else, that control can tell the VF4AM ECU the requests which could control the shifting, and at the same time your controls could trigger the relays that fool the 3rd gen ECU into operating the indicator lights.

 

I think a better way to go about it would be to keep the stock 3rd gen Tacoma 4wd ECU in place, and re-pin the plugs that go into the VF4AM t-case actuator assembly. So the stock 4wd ECU would drive the VF4AM actuators. That would allow for the least amount of butchering of the factory wiring harness. The stock 4wd ECU would be able to control the ADD for the front diff, and the selection of Hi/Lo range. The stock 4wd computer would not be able to control the center differential lock/unlock functions. This could be solved in much the same way as when people retrofit rear elockers into their trucks and use an aftermarket wiring harnesses that are available to control the rear elocker. With some modification to the plugs, such an aftermarket harness could be adapted to control the locking center differential instead of a locking rear differential, using the center diff lock push button I posted above. Or one could simply create this harness if savvy enough with relays and such. I have one of these aftermarket harnesses when I retrofitted my elocker into my 3rd gen 4Runner.

 

Without reading the actual FSM, it's a bit difficult to determine exactly how the VF4AM shifts the center diff lock.....however, I feel like you're going to run into trouble with it since it has an extra motor in the t-case actuator that appears to be specifically for that CDL function. Our 3rd gen ECU wouldn't have the logic to drive that motor back and forth. If it's like the other motors, then it's also looking for feedback from the actuator to tell it to stop powering the motor once in position. But again, that's a bit hard to tell all of that from the diagram by itself.

As far as I'm aware, the stock 4th gen 4R uses a momentary CDL switch on the steering wheel, takes that signal and applies it to the center diff lock motor as long as the transfer case is in a 4WD mode.

For what it's worth, you can adapt your wiring at the ECU by buying a 2Lo kit if needed. I don't know if the connectors that you would need for the 4R ECU are easily available though. But you could definitely take care of the Tacoma side of things.

 

I'm thinking you didn't read my previous post in its entirety, because you're repeating back to me some of the things I already stated (such as 3rd gen 4wd ECU not having the logic to drive the center diff lock motor back and forth). Yes, the VF4AM center diff would need to be controlled outside of the stock 3rd gen Tacoma 4wd ECU. I think this would be relatively easy using a series of relays that supply power based on the position of the push button, and also the limit switches inside the center diff. The easiest way to do this would be to buy one of the after market rear elocker harnesses that are available (these also drive a single motor with limit switches) and modify it to drive the center diff locker instead. Would make for a cleaner install, and keeps the stock 4wd ECU so nothing changes with the CAN system.

 

Are @6 gearT444E @BassAckwards in here yet?

 

I did read your post, but I guess I am not familiar with aftermarket lockers that use limit switches. So when I read the plan to use a locker switch, I still didn't think that would accomplish the CDL logic you're after. Only aftermarket electronic locker actuation styles I've seen are just simple on-off to an electromagnetic clutch like Eaton. If you found a locker harness that will offer that functionality then you should be fine.