Shift to 4H while driving?

[RonJR]

The chain drive J-shift manual transfer case for the 2nd gens (pretty sure this is the same case for the early J-shift 3rd gens) has two synchros, one on the range selector and one on the 2-4 selector.
- Shifts from 2H to 4H are synchronized and can be done on the fly, as stated above.
- Shifts from 4H to 2H do not require synchronization and can be done at any speed.
- Shifts from 4L to 4H are synchronized and can be done on the fly.
- Shifts from 4H to 4L are not synchronized and require a complete stop with transmission in neutral for automatics or clutch depressed for manuals.

20 years of wear may change the effectiveness of the synchros.

This info does not apply to the newer multi mode transfer cases.

 

[phattyduck]

Here's what my card says:

('99 SR5 auto, standard j-shifter)

So, in or out of Low range (notice arrow goes both directions) should be stopped in Neutral with the automatic trans.

Into 4H below 50mph, no mention of limitations on going back to 2H, just suggestions for how to get the ADD to unlock, basically.

-Charlie

 

[BrianSD_42]

Well here's a question for y-all .....

A) How many people here in this thread have an auto with electronic J-shifter and can successfully shift Hi/Lo while moving with zero grinding?

B) 2nd question .. how many miles do you have


Me .... 1997 Auto Limited. 251K miles. I use the button to shift 2HI <--> 4HI while driving with no issues, ever. But I must stop and turn off the truck when shifting the transfer case 4HI <---> 4LO or there will be grinding. I used to be able to do it on the fly, many years ago just fine. Then I had to stop and go in transmission N but could leave the truck on. Now I to turn off the truck as well to experience no HI/LO, LO/HI grinding sound.

:bigok:

 

[RonJR]

I think the auto is tough on synchros, since it is hard to make the auto tranny let go of the output shaft completely. So the synchros have to overcome the drag of the auto transmission. For a manual, if the clutch is releasing properly, the synchros have a much easier time of it.

 

[phattyduck]

A) How many people here in this thread have an auto with electronic J-shifter and can successfully shift Hi/Lo while moving with zero grinding?

I haven't seen one place that says it is ok to shift ranges (H-L or L-H) while moving with the auto trans (j-shifter, electric part time or multi-mode). Can you post something that says this is ok?

Even on the manual trans, it says to stop the vehicle, then mentions that you can do it at less than 5mph.

-Charlie

 

[BrianSD_42]

I haven't seen one place that says it is ok to shift ranges (H-L or L-H) while moving with the auto trans (j-shifter, electric part time or multi-mode). Can you post something that says this is ok?

-Charlie

Look at the visor pic posted twice now. Both imply that doing it at 5mph is ok unless you encounter issues.

Essentially what I'm saying is most of us with an auto will encounter issues.

 

[RonJR]

I mis-spoke in my previous post. After looking at the FSM again, it's clear the manual transmission version of the tcase has a 4L to 4H synchronizer, upshifts can be made on the fly. The automatic transmission version does not have that synchro, so stopping or shifting below 5mph is necessary. This corresponds with the placard posted above.

 

[phattyduck]

Look at the visor pic posted twice now. Both imply that doing it at 5mph is ok unless you encounter issues.

Essentially what I'm saying is most of us with an auto will encounter issues.

I think you need to look at it again. The section that says up to 5mph is for the manual transmission. Auto transmission says stop the vehicle.

-Charlie

 

[RedYota1388]

I wonder what my Son does! He has a two transfer case thing setup in his 87 rock Crawler! I bet something grinds sometime in the crazy shift variables.


Sent from my iPhone using Tapatalk

 

[Scramble]

I think you need to look at it again. The section that says up to 5mph is for the manual transmission. Auto transmission says stop the vehicle.

-Charlie

LOL, I couldn't imaging shifting into 4low going faster than 5mph. It's like downshifting into 1st gear where you bash your forehead on the steering wheel! LOL

 

[BrianSD_42]

I think you need to look at it again. The section that says up to 5mph is for the manual transmission. Auto transmission says stop the vehicle.

Yes it does say that auto ... Stop.

-Charlie

The instructions could certainly have been written better.

:bat:

 

[phattyduck]

The instructions could certainly have been written better.

:bat:

Seriously? What level is your reading comprehension?!?!?

The line above what you wrote says "Depress the clutch pedal" and the line above that is "Manual Transmission" ... as in, doesn't apply to automatic.

Then the line below, that actually applies to the "Automatic Transmission" states, "Stop the vehicle, then shift the transmission into "N" first"

-Charlie

edit: or were you agreeing with me? In which case, I'm sorry!

 

[BrianSD_42]

I don't disagree with you man. But yes the first time I saw that pic it wasn't clear. Could be the picture or just my brain. Thanks for posting clarification btw.

 

[octanejunkie]

"This shit reads like stereo instructions" says the 2WD guy

My 93 4WD standard shift Pathfinder was great and shifted on the fly for the first 10 years - then it wanted to grind, even in Neutral, until eventually it wouldn't shift into 4H anymore at all

The day I sold it I went to show the buyer that 4WD was a no go and it shifted into 4H with no problem at all.

Now I just need to decide WHICH variation of Toyota transfer case I want to put in my rig :hatsoff:

 

[phattyduck]

Now I just need to decide WHICH variation of Toyota transfer case I want to put in my rig :hatsoff:

FJ Cruiser MT transfer case... full time 4WD (torsen center diff) and all manual actuation. :boxing:

-Charlie

 

[octanejunkie]

FJ Cruiser MT transfer case... full time 4WD (torsen center diff) and all manual actuation. :boxing:

-Charlie

This is like feeding the fat kid cake while he's on the treadmill :hungry:

 

[Scramble]

"This shit reads like stereo instructions" says

Now I just need to decide WHICH variation of Toyota transfer case I want to put in my rig :hatsoff:

Manual everything.

 

[octanejunkie]

Manual everything.

That's what I'm used to, TBH, but in LA traffic...

 

[diverscale]

Well here's a question for y-all .....

A) How many people here in this thread have an auto with electronic J-shifter and can successfully shift Hi/Lo while moving with zero grinding?

B) 2nd question .. how many miles do you have


Me .... 1997 Auto Limited. 251K miles. I must stop and turn off the truck when shifting the transfer case or there will be grinding. I used to be able to do it on the fly, many years ago just fine. Then I had to stop and go in transmission N but could leave the truck on. Now I to turn off the truck as well to experience no HI/LO, LO/HI grinding sound.

:bigok:

1998, 220 000 miles, J shift. I live in snowland, 6 months of snow a year. I always shift from 2HI to 4HI on the go. Some days I have to shift in and out 3-4 times while going to work, as I get on asphalt then snow depending on the area.

80KM/h is a bit too fast, as it tend to be hard to get in, and I do not want to force it. But any time, it will go in at 70KM/H and under. I never stop to get into 4HI and never get any grinding sound.

I do always remove my foot from the throttle while shifting to prevent slipping and never shift into 4HI into any kind of curve.

I do always completely stop to get into 4LO

 

[Tyler James Inc]

Omg!
Never in a million years would I even consider going from HI to LO while in motion!
Holy smokes.
No; do not do that.