Transfer Case Question

Does anyone have schematics or more information on how the tcase works in the 3rd gen Tacoma’s (MT if it matters). I’m a mechanical engineer (education, not by trade) so I know how transfer cases work in general, but I’d like to know more specifics. I.e. is the gear reduction accomplished through regular gears or a planetary gear set? What exactly is the actuator...ehm...actuating...a hub sleeve?. I’m assuming there’s no synchronizer or anything?

I guess this is what I’m really getting at: Is there anyway at all to shift from LO to HI without stopping? It’s not a big deal, but there are times when I’d really rather shift on the fly than stop and wait for it to do it’s thing. I kinda wish it were a manual transfer case and I could float it back and forth. (If it can’t be done that’s fine but don’t bother telling me it’s a bad thing to do, I’m stubborn and full of bad habits )

Thanks in advance!

 

No thiers not a way to shift from high to low or low to high unless fully stopped BTW you should not try it on any 4 wheel drive PERIOD it's absolute hell on gear teeth especially T cases with planetary reduction IF you can convince the planetary to go into a different range......I doubt it will ever happen without alot of noise.

In the days of the new process 205 you could yank on the lever to do it but omg it sounded very painful......and yes it did alot of damage to the gear teeth

I wouldn't attempt it

 

Gotcha, I was just curious bc I heard of people with older trucks and Jeep’s being able to rev match their way back and forth. I figured if there was a way of doing this then I’d be able to. I drove a Miata for a few years that for all intents and purposes was unsynchronized.

Regardless, I’m a huge nerd and would seriously like any info I can get on the thing. I’ve seen really good videos and animations of trannys and diffs, but haven’t found anything like that for tcases.

 

Its not feasible because the rotational mass of the tires and drivetrain can't just be jerked into a different gear like that.

4wd High is easier to sync because all that has to happen is the front and rear wheels be going the same speed

 

It’s a planetary reduction at the front of the case. 2-4 is at the rear with a synchro. Actuator moves 2 shift rods with forks to slide the L-H and 2-4 sleeves.

Jeff

 

The more interesting transfer cases are the VF4[AM/B/BM] series, which have the following modes:

High-Range 2WD (VF4AM only)
Part-Time High-Range 4WD (Locked)
Full-Time High-Range 4WD (Torsen LSD)
Part-Time Low-Range 4WD (Locked)
Full-Time Low-Range 4WD (Torsen LSD)

On the VF4AM there are 3 shafts - 2 moveable and 1 fixed. The H-L is basically the same as the Tacoma, again using a planetary reduction, the interesting part is the second shaft, which has 3 positions, 2-4F-4L floats the fork on the shaft with end stops (using snap rings) with the shaft using interlock pins to sliders on the fixed shaft prevent the fork from moving in all 3 locations. It's pretty cool.

It would also be very easy to implement Low-Range 2WD on the VF4AM, but Toyota has never done so. The fools.

Jeff

 

Some info here

https://atracom.blob.core.windows.net/webinars/import/toyota_4x4.pdf

Some info in my t-case swap thread, some links are now dead.

https://www.tacomaworld.com/threads/transfer-case-swap-multi-mode-2wd-awd-vf3am-vf4am.627123/

Dig through the new car features in this link. The Hilux, Fotuner, and LC Prado have t-cases that are the same or similar, and much info exists in there.

http://zatonevkredit.ru/new_car_features/

 

Miss my old 4runner and XJ, you could crash into 4LO as long as you timed it juuuuuuuuust right.

 

I used to wish for that on the Taco until I flicked in while moving a bit. Not anymore. That actuator is not gonna stop once it decides to go.

 

Thank you, this is EXACTLY what I was looking for. I’ve given up on my “idea” but like I said, this is super cool stuff to me

 

You are welcome.

There is a synchronizer in there... Less than 2mph in the MT and it should shift. I believe the manual even says this.

 

You can shift a manual without a clutch just as you can with a transfer case. You just need to match the speeds.

 

The big dogs came out tonight. Nice.

 

No. You gotta stop.

 

This is all true.

(Auto won't let you shift 2-4 unless stopped, MT will do it if you're below 2 mph).

Jeff