Neutral is not so neutral.

[MossJenks]

I've rebuilt a couple of manual transmissions and know precisely how they work. My 5th gen though is the first auto vehicle I've ever owned and really don't know much about how an auto box works.

I've noticed lately when shifting from 4high to 4low and back that neutral doesn't seem to be completely neutral. I get grinding with the engine on and in neutral. Sometimes it's slow (clack-clack-clack) but sometimes pretty fast and I have to shut off the motor to shift it. Not a huge deal in itself since I usually air up and down at the same time, but it seems like it might indicate a problem.

So what does it mean when neutral is not so neutral?

Thanks,

Chris

 

[MossJenks]

Transfer case actuator? Mine has a good old fashion lever. The problem here is that the case is still getting drive even with the transmission in neutral. My question is: why is it getting drive in neutral.

 

[wfo9]

N is Neutral nothing is being driven. To shift from between 4L and 4H you need to be at a complete stop with the transmission in N. Do it in one quick movement as there may still be some some slight internal movement of the trans output shaft with no actual tq behind it. The movement can happen as the TCases goes into the N position.. That is the reason to do it as one quick movement.

Also don't go directly in and out of 4wd while doing this. Shift in and out of 4H while moving in Drive.. but do the 4Lo transition while at a complete stop in N.

 

[Hadelson]

I've rebuilt a couple of manual transmissions and know precisely how they work. My 5th gen though is the first auto vehicle I've ever owned and really don't know much about how an auto box works.

I've noticed lately when shifting from 4high to 4low and back that neutral doesn't seem to be completely neutral. I get grinding with the engine on and in neutral. Sometimes it's slow (clack-clack-clack) but sometimes pretty fast and I have to shut off the motor to shift it. Not a huge deal in itself since I usually air up and down at the same time, but it seems like it might indicate a problem.

So what does it mean when neutral is not so neutral?

Thanks,

Chris

I've had an SR5, TE and now TRDP. Find going from 4L to 4H or 2WD a royal PIA. Manual says stop, apply brake and shift smoothly from 4L out to the other selections. Son of a gun always grinds. I've tried multiple different ways with same result.

What I do to avoid grinding coming out of 4L is stop. Apply brakes, turn off engine and then shifts smoothly without grinding to either 2WD or 4H.

Hope this helps

 

[BobsTrail]

To shift from between 4L and 4H you need to be at a complete stop with the transmission in N. Do it in one quick movement as there may still be some some slight internal movement of the trans output shaft with no actual tq behind it.

As [MENTION=106176]wfo9[/MENTION] said, do it in one quick movement. I had the same grinding until another member told me to be quicker on the shift and don't pause in neutral.

 

[Antman]

It sounds bad but it isn't hurting anything. Relax.

 

[MossJenks]

I'm not sure I can relax on that one - I've been driving these things for 30 years and this one is the first one that gives me a nasty grind from the transfer case. As long as it's "normal" for an auto though I won't worry about it, I'll just work around it.

N is Neutral nothing is being driven. To shift from between 4L and 4H you need to be at a complete stop with the transmission in N. Do it in one quick movement as there may still be some some slight internal movement of the trans output shaft with no actual tq behind it. The movement can happen as the TCases goes into the N position.. That is the reason to do it as one quick movement.

If it seems like the input to the case is turning slowly then one quick movement works with just a quick clack-clack grind. But when it seems to be moving faster it's a pretty wicked grind. Of course the only way for me to tell which is which is by grinding it!

I've had an SR5, TE and now TRDP. Find going from 4L to 4H or 2WD a royal PIA. Manual says stop, apply brake and shift smoothly from 4L out to the other selections. Son of a gun always grinds. I've tried multiple different ways with same result.

What I do to avoid grinding coming out of 4L is stop. Apply brakes, turn off engine and then shifts smoothly without grinding to either 2WD or 4H.

Well at least I'm not alone so won't worry too much about it. That's exactly what I do - turn the engine off. Then there's nothing moving to grind.

 

[wfo9]

If it seems like the input to the case is turning slowly then one quick movement works with just a quick clack-clack grind. But when it seems to be moving faster it's a pretty wicked grind. Of course the only way for me to tell which is which is by grinding it!



Well at least I'm not alone so won't worry too much about it. That's exactly what I do - turn the engine off. Then there's nothing moving to grind.

Your statement confuses me a bit.. When it is moving slowly vs faster... It can't be moving at all.

When stopped .. There is no movement. When the t-case moves from 4L past N it may start to move a little (but with no torque behind it in N, D is another story). If you move it fast it should make no noise. Mine never makes a noise and most people using the proper technique don't hear anything. If you do it slow and without a sharp positive yank.. it will make some noise, but nothing to worry much about as long as you are not in D or R

 

[BobsTrail]

Our T4s are confusing sometimes. When I play with Crawl Control, I have to go to 4L first, then put it in D to turn on CC. Since I'm already in D, it's easy to forget and try to go right to 4L and wonder why the shifter won't move.

Another member said that it feels like setting up the Star Ship Enterprise flight deck with all of the controls -- CC, MT, ATRAC, Transfer case.
:iagree:

 

[wfo9]

Our T4s are confusing sometimes. When I play with Crawl Control, I have to go to 4L first, then put it in D to turn on CC. Since I'm already in D, it's easy to forget and try to go right to 4L and wonder why the shifter won't move.

Another member said that it feels like setting up the Star Ship Enterprise flight deck with all of the controls -- CC, MT, ATRAC, Transfer case.
:iagree:

LOL. you should see what it is like to drive a hard core rock crawler.. Some have as many as 15 additional controls that need to be worked. It takes some major skill.
- front steering
- rear steering
- front drive engagement
- rear drive engagement
- transmission gear shifter
- transfer case speed (usually at least 3 speeds sometimes 4)
- individual levers for each brake (cutting brakes) (up to 4 levers)
- locker front
- locker rear
- suck down front
- suck down rear

side note. Atlas transfer cases are synchronized.. So you can actually switch reduction gear on the move.. Pretty cool. Also they all allow you to engage front/rear individually for digs (very useful)

 

[MossJenks]

Your statement confuses me a bit.. When it is moving slowly vs faster... It can't be moving at all.

Well yeah - that's the point of this entire thread!! With the vehicle stationary and the transmission in neutral there IS movement in mine. If there were no movement there would be no grinding. Some times I can tell it's slow because there is a slow grind - clack, clack, clack - and sometimes its obviously moving faster because I get a faster grind - more like a manual transmission with a bad syncro. It can't be movement in the output of the T-Case since the vehicle is stopped, so it must be that the engine is still turning the input.

 

[MossJenks]

Ah crap. Friggin spammers.

 

[wfo9]

Well yeah - that's the point of this entire thread!! With the vehicle stationary and the transmission in neutral there IS movement in mine. If there were no movement there would be no grinding. Some times I can tell it's slow because there is a slow grind - clack, clack, clack - and sometimes its obviously moving faster because I get a faster grind - more like a manual transmission with a bad syncro. It can't be movement in the output of the T-Case since the vehicle is stopped, so it must be that the engine is still turning the input.

Just to clarify. There is no movement of the input or output when you are at a stop in N with the T-case in 4L or 4H. However, when you transition between the two and briefly hit N on the t-case some pressure in the converter is released and the input may start to move. But it should not have a chance if you do it quickly in one quick motion.

 

[Ron4RNevada]

I've driven my cousins 2010 SR5 (lever), my own 2013 SR5 (dial), my brothers 2018 SR5 (dial) shifted them all 2H, 4H and 4L lots of times. None of them make noise or give me trouble.

Perhaps you need more practice and more time in the dirt.

 

[MossJenks]

I've driven my cousins 2010 SR5 (lever), my own 2013 SR5 (dial), my brothers 2018 SR5 (dial) shifted them all 2H, 4H and 4L lots of times. None of them make noise or give me trouble.

Perhaps you need more practice and more time in the dirt.

You're right. I've only got about 30 years of experience in the dirt and have only put around 350k miles on 4Runners. I've only done serious off-roading in a 1957 Willys, a 1975 Jeep. a 1988 4Runner, a 1990 Isuzu Amigo, a 1995 Toyota Tacoma, a 1998 4Runner and now my 2011 4Runner. I need another 30 years and 350k miles. Though that might not help in that I used to know how to work mine but apparently I've forgotten lately. Maybe I should get one with the dial so I can at least attempt to learn that complication.

Please, kind sir, tell me what the proper technique is? I've always stopped the truck and put it into neutral (or just put in the clutch with a manual transmission), then I've done the 4Hi - 4Lo shift. Obviously that's the newb way though. Please let me know the proper way to do it. Thanks :ybrick:

Let me approach this a different way - forget the T-Case. I know all about how it works and how to operate it. This is about the auto transmission - what would make neutral in an automatic transmission vehicle not be so neutral?

 

[MossJenks]

Just to clarify. There is no movement of the input or output when you are at a stop in N with the T-case in 4L or 4H. However, when you transition between the two and briefly hit N on the t-case some pressure in the converter is released and the input may start to move. But it should not have a chance if you do it quickly in one quick motion.

I agree that there SHOULD be no movement but there is. And mine keeps spinning - once I'm in neutral I can't get out either way, even if I keep trying. Repeatedly grinding against it doesn't seem to slow it down at all, so the transmission has to be continuing to drive it. The quick movement thing works when it seems to be grinding slowly but not when it's grinding fast. Part of that is my mechanical sensitivity. I hardly ever break anything but I do that by not forcing the issue - so when I get a big grind I back off instead of just saying "screw it" and jamming it in no matter how nasty it sounds and feels.

 

[keph13]

So I noticed this issue and looked into it, and discovered something fascinating (to me, anyway). Here's my recollection, anyone feel free to correct me if I get anything wrong:

Auto transmissions have a torque converter, which (at a basic level) has two pieces with a viscous fluid between. When you're driving, they're more or less attached to each other (either with a mechanical addition based on wheel speed, or by the friction of the fluid). When you're stopped but in drive, the wheel-side piece is unable to move, so the fluid is sort of aimlessly spinning. This site has a good analogy - think of two fans, one pointing at the other. The first will spin the second, but if you hold the second still the first doesn't get stuck.

However, when you're in neutral, the wheel-side piece is disconnected from the thing stopping it (the wheels and brakes), so it can start moving again. The addition of a 4wd transfer case complicates matters, but essentially with everything in neutral the various pieces between the axles and the engine can spin to some degree, causing your grinding when you go to shift out of neutral. That's why the smooth motion is important - there's not enough time in neutral for the fluid to start the transfer case spinning.

 

[Louise]

I've only done serious off-roading in a 1957 Willys, a 1975 Jeep. a 1988 4Runner, a 1990 Isuzu Amigo, a 1995 Toyota Tacoma, a 1998 4Runner and now my 2011 4Runner.

Okay, I call BS. You can't drive 7 cars at once.

 

[Jeremy556]

Have you flushed or drained/refilled your transmission? Perhaps overfilled or used a trans fluid other than Toyota WS?

As others have mentioned, the torque converter is a fluid clutch - when the transfer case is engaged with the wheels, there is no movement. As soon as you hit neutral on the transfer case between 4hi and 4lo, the small amount of torque coming out of the transmission will begin to turn the shaft and cause the grinding you are experiencing.

If you are familiar with motorcycles, you can see basically the same thing happen with a wet clutch when the bike is on a rear or center stand with the rear wheel off the ground. When the engine is running and trans in neutral, the rear wheel doesn't move. If you put the transmission in gear and pull the clutch, the wheel will turn slowly as torque is transferred through the engine oil between the clutch friction plates.

 

[mo_mo]

I agree that there SHOULD be no movement but there is. And mine keeps spinning - once I'm in neutral I can't get out either way, even if I keep trying. Repeatedly grinding against it doesn't seem to slow it down at all, so the transmission has to be continuing to drive it. The quick movement thing works when it seems to be grinding slowly but not when it's grinding fast. Part of that is my mechanical sensitivity. I hardly ever break anything but I do that by not forcing the issue - so when I get a big grind I back off instead of just saying "screw it" and jamming it in no matter how nasty it sounds and feels.

In an auto trans there is a small amount of torque going through the viscous coupling and the transmission. Even with the planetary set to free wheel there is a small amount of torque on the input shaft that will get transferred since the world isn't perfectly frictionless inside the transmission. That creates a small speed differential between shafts at the transfer case if let the transfer case hangout in neutral for a brief period of time (hence why everyone says to just push the transfer case quickly through neutral from H to L).

Jeremy556 is onto the same small amount of torque being transferred through a wet clutch even when the clutch is pulled to 'open' the plates and allow full slippage on a motorcycle.