Shifting Transfercase on the fly in an auto

[leehamescort]

G'day,

I can shift from low to high range while moving if I get the revs right with my hilux geardriven transfercase in my surf with a R151 manual gearbox.

Would I be able to do the same thing with an auto or wont it work as you cant take the load off the drivetrain as there is no clutch? shift the auto into Neutral?

Do most comp truck (cliffhanger/OBC) need to stop to go from Low to High?

I'm trying to choose the best transfercase setup for my new build which i hope to eventually use in OBC/Cliffhanger and was wondering if shifting on the fly is something I need / many people have?

Drivetrain in new build in 350chev + TH350 Auto + ??

Thanks for any help.

Leeham

[DR Frankenstine]

All the auto's ive driven you have to stop. Even to go from 2H to 4H with the hubs in.

[macca81]

hey leeham, the standard surf auto wont allow you to shift from hi-lo or vise versa unless you are stopped and either in neutral or park. shifting from h2-h4 can be done upto 80kph (acording to the manual anyways, im sure it can be shifted at any speed, but who needs to shift into 4wd at 120kph??)

[Turoa]

on my discover (with lt230) I can put it in neutral and shift it, but only at 30k max

[Mr DJ]

Yea, mine is the same, need to be stationary to change between High and Low range.

[leehamescort]

on my discover (with lt230) I can put it in neutral and shift it, but only at 30k max

So it might work then....

I know its not recomended (by the book) to go between high and low on the move. Just that in real life the ablity that i have now to shift from Low range to High range on the move come in handy from time to time and was hoping to retain that abilty with the new auto setup.

Guess i'm just going to have to build it and see what happens.

cheers.

[ozrunner]

Leeham

Just for your info the 4Runner auto will do all that and more no problems as well as shift from high to low while moving, ie it can be accidently slotted into low at 100kph as the ecu won't allow this change to occur until all the rpm's are correct etc so at normal 4wd pace it will also change from high to low range no problems.

But it's 4wd transfer is hydraulic and not something you would use in comps nor the basic toy auto etc.

I'm surprised a normal auto can't be shifted from low to high though as auto's do have slippage via the converter . Shame the Toy transfer doesn't have synchro's

Maybe check what other transfers are available that may do this that will bolt to a T700.

Check with the Pirate 4x4 boys

JD

[Mr DJ]

Just a thought leeham, try a rear housing from an AW4 jeep auto (same aisin auto as Toyota A34#) and you can bolt a dana TC straight up to it.
May give you other options.