I wonder if you can upgrade your differentials with a limited slip? Or would that be more trouble than it’s worth?

The V6 4th gen actually had the multi-mode transfer case. So it had 2wd, Full-time 4wd, and Part-time 4wd (locked diff in the T-case) choices. It's really the most versatile system.

Some 3rd gens also had the Multi-mode T-case.

Are these the same thing, just different versions?

-gl

Different brands which perform the same function. Which is to amplify/modify the Drive By Wire signal between the gas pedal and the computer.

I think the lack of multicolor also has to do with mpg on the EPA test. The basic transfer case in 2wd is more efficient. But the 4R gets pretty terrible mpg in any trim by modern standards. I'm not sure it's meaningful.

I'm sure it's cheaper to build the simpler transfer case and that's probably the biggest driver. Toyota cut a lot of costs on the 5th gen in various places. This was probably one of them.

I'm really surprised that the new tundra didn't come with a multi mode transfer case. Especially for a $70-80k trim. It's the only full size without it. My guess is that the Borg Warner auto 4wd system doesn't meet Toyota's durability requirements. It's a clutch based system and clutches wear out. Plus they have a torque limit where they'll slip even fully "locked". They're great on the highway. Probably not very good long term in the dirt though. Apparently use like snow plowing will ruin the clutches in short order. They're really only intended for slippery highway use and occasional off road. I can see why Toyota said no to the Borg Warner TOD design. But Toyota could have used an aisin transfer case.

Toyota's torsion differential is much better for longevity, but also more expensive to manufacture.

I had a 4th gen V8 before my 5th gen V6. The V8 had more low end torque, the V6 more high end HP. I'll take low end torque over high end HP any day.

I think the lack of multicolor also has to do with mpg on the EPA test. The basic transfer case in 2wd is more efficient. But the 4R gets pretty terrible mpg in any trim by modern standards. I'm not sure it's meaningful.

I'm sure it's cheaper to build the simpler transfer case and that's probably the biggest driver. Toyota cut a lot of costs on the 5th gen in various places. This was probably one of them.

I'm really surprised that the new tundra didn't come with a multi mode transfer case. Especially for a $70-80k trim. It's the only full size without it. My guess is that the Borg Warner auto 4wd system doesn't meet Toyota's durability requirements. It's a clutch based system and clutches wear out. Plus they have a torque limit where they'll slip even fully "locked". They're great on the highway. Probably not very good long term in the dirt though and may not hold up well to the hybrid's torque. Apparently any kind of frequent use will ruin the clutch packs. That's why you can't snowplow with them for example. The transfer case can't handle constant engagement.

Toyota's torsion differential is much better for longevity, but also more expensive to manufacture.

I would guess that it would be pretty straight forward to swap out the part time transfer case for the limited slip transfer case from the Limited. I would guess that the mounting points and drive shaft (U Joint) connections would all just bolt together. I certainly could be wrong about this.

You'd have to put the dial switch from the limited into the spot where the lever is and wire the electronics, but again, all parts should fit into the same location. It's even possible that the wiring harness is already in place, just plug in the appropriate connectors.

I'm not sure how all the traction control software would work though. Is the software depending on the transfer case being locked? Would a limited slip confuse it? Unanswered questions.

This seems possible, but I have not heard of anyone doing this. I don't want to be the first. If many people have done it and know what to look out for, perhaps some aftermarket manufacturer makes a kit with the parts you need, that would be a different story.

Aftermarket rear lockers are pretty common, if replacing the transfer case were as common as rear lockers are, I would strongly consider it.

To OP: I made that switch, went from 2005 V8 4x4 to 2013 Trail with KDSS.
I do not tow frequent enough to miss V8 and V6 is totally fine for everything else.
I love 5th gen a lot more then I loved my 4th gen…
IMHO 5th gen is just a better SUV overall: size, ergonomics, utility, looks (very biased here, since I have unicorn model).

Good luck with your decision!

My old Hilux Surf had the multi-mode TC, I really liked the versatility it provided. I don't know that I've ever been in a V6 4th gen, I didn't realize that's the TC they came with, good info.