Auto Transmission - 2WD Low vs 4WD Low?

[farmerjon]

On my last wheeling trip, I had some steep, steep hills to go down, and I was getting tired of riding the brake in 2WD Low, just wasn't cutting it. So I stopped, and put the truck in 4WD Low, AND, the auto shifter in Low... That got some serious gears kicking in, and it slowed down the truck big time...

My question is, am I getting some kind of "double" effect, or is the 2Low not doing anything if the truck is already in 4Low? How does that work?

And no, I didn't try (that time) with just 4Low - but I think I remember 4Low being faster than what I was going... Should have tried it, but didn't think of it. This question keeps coming back to my back burners of thinking even weeks later, so am curious!

Thanks! Just one of those guys who wants to know how things work... :yo:

 

[Asaspades93]

I read a post about this a few weeks ago so someone point out if I am wrong and I can delete this post.

As I understand it the 2 and L on the shifter will prevent the transmission from shifting higher than that gear, only first and second when on 2, only first on L. Putting it into 4lo actually changes the gear ratio but doesn't affect what gear it will shift up to. I don't think it would have a double advantage. I haven't tried but I wouldn't want to go fast enough in 4lo to get past second so I think leaving it in drive is more than enough.
That is just how I understood the post I read so I hope I explained that correctly

 

[slapdappy]

engine braking

4 low is great for creeping downhill. I keep trans lever on L, figuring if I need 4 low I don't want or need the trans to shift into 2nd or 3rd. I always have OD off when wheeling.
4 hi with trans lever on L is also good for downhill.
Engine braking, my friend. Engine braking.

Where in The Rugged Rockies?

 

[snivilous]

Not sure what you're asking, but if I'm understanding your post then [MENTION=94063]slapdappy[/MENTION] is right. You still need to force the tranny into lower gears to get the engine compression you want to slow you down if you are in low range or high range (for the transfer case).

From my experience the transmission will go into 3rd gear (not into 4th/OD) with the transfer case in low range, but you can still do 20+ mph easily which is why for going downhill you need to drop it into 2nd or 1st gear with the shifter just like for normal engine braking in high range.

 

[BrianSD_42]

am I getting some kind of "double" effect, or is the 2Low not doing anything if the truck is already in 4Low? How does that work?

When you switch the 4WD shifter into 4LO you are actually disengaging from the gears in the transfer case to 2nd set of transfer case gears.

Your transmission still has the same gears 1, 2, 3, O (although O is probably disabled) and you will feel them shift as you drive in 4LO the same as HI.

My strong advice ... always stop the 4Runner completely, put it in N then shift from 4LO -> 4HI or 4HI -> 4LO.


:bathbaby:

 

[KidVermicious]

Let's back up - what do you mean 2wd low, Jon? Unless you've done some expensive modding, you can't put your truck in 2wd low range. You've got 2wd high range (only the two rear wheels are powered, no gear reduction), 4wd high range (where all four wheels are powered, no gear reduction), or 4wd low range (where all four wheels are powered and the transfer case reduction gears are engaged).

The guys above are correct that when you move the transmission selector to L that the truck will hold in first gear no matter how fast you're going, but I suspect that you're confusing the L on the gear selector with low range in the transfer case, which are two completely different things.

 

[GhostDog]

^^ This

"Low" on your transmission has a gear ratio of 2.804:1
When you shift into 4Hi your transfer case has a ratio of 1:1 so it takes your transmission gearing and multiplies it by 1.
When you shift into 4Lo your transfer case has a ratio of 2.566:1 now it takes your transmission gearing and multiplies it by 2.566.

 

[tre9er]

Let's back up - what do you mean 2wd low, Jon? Unless you've done some expensive modding, you can't put your truck in 2wd low range.

I've not tried it, but I always wondered if you put the TC into Lo, but didn't hit the 4WD button, if it would put you into Lo even though the front isn't engaged...? Make sense? A buddy back in the day with his 79 Chevy used to keep the hubs unlocked and put it in Lo and run around town to hear his loud pipes.

 

[KidVermicious]

Couldn't tell you, all my 4Runners have had manual transfer case selectors. Try it and see what happens, but I suspect the computer won't let you do it.

I can accomplish the same thing on my '85 if I put the truck in 4low and leave the hubs unlocked, and if I pick up a twinstick setup I can do it from the cab, but I think a 3rd gen would need to convert to an early gear drive tcase before you'd get the same options?

 

[tre9er]

the T-case has manual shifter for 4L, N, and 4H, but the 4x4 engagement is push-button. That makes me think you'd be in low, whether or not you engaged 4WD

 

[GhostDog]

I've not tried it, but I always wondered if you put the TC into Lo, but didn't hit the 4WD button, if it would put you into Lo even though the front isn't engaged...? Make sense? A buddy back in the day with his 79 Chevy used to keep the hubs unlocked and put it in Lo and run around town to hear his loud pipes.

Not sure what 4wd button you thinking of (center diff lock?) but our 4runners do not have the ability to run 2wd with the tcase in low without mods.

 

[tre9er]

Not sure what 4wd button you thinking of (center diff lock?) but our 4runners do not have the ability to run 2wd with the tcase in low without mods.

This one:


I see now that it's "4L" not just "L", but I always wondered how that works. Can I NOT shift to 4L without hitting the 4wd button? Will it not let me? Or if it will, will no wheels spin or something?

 

[csp]

OP,
The "L" on the transmisison gear selector just means first gear in the transmission and it will not automatically upshift into other gears as you drive. This is true regardless of what position the transfer case shifter is in.
The L on the transfer case means low range, or an additional set of lower gears, regardless of where the transmission gear selector is located.

You need to understand that the transfer case is a separate additional gearbox with its own sets of gears to select from. It also is what sends power to the front axle. In 2wd you are still in high range, so the gear reduction isn't as great.

First 4wd I take it?

 

[papapoopski]

[MENTION=81047]farmerjon[/MENTION]

I was playing with 4L on the transfer case a while back and moved the transmission shifter into L which gave me some serious engine braking for rolling downhill. Is this what you did? and are you looking to find out what the mechanics are? If so, me too...

With regard to shifting into 4L without engaging the 4WD button on the shifter first...IME with my 2002, the front differential will automatically engage when shifting into 4L whether you want it to or not. The middle transfer case will not engage unless you activate it whether or not you are in 4HI or 4L

 

[tre9er]

With regard to shifting into 4L without engaging the 4WD button on the shifter first...IME with my 2002, the front differential will automatically engage when shifting into 4L whether you want it to or not.

This is what I wondered. Otherwise why specifically put "4L" whereas the bottom position is just "H"

 

[twitchee2]

Brian2Sun is dead on.

Just to add some confusion to the mix, I can actually put my 02 in 2wd low range. it has to with my trac off switch. When I hit the switch, the ECU thinks it is already in 4wd so it will not engage the front tires. It is pointless but can be fun at times when I want to the challenge of 2wd but want to keep things cool with low range.

 

[twitchee2]

This one:


I see now that it's "4L" not just "L", but I always wondered how that works. Can I NOT shift to 4L without hitting the 4wd button? Will it not let me? Or if it will, will no wheels spin or something?

My 02 automatically engages 4wd when putting the transfer case into low range.

 

[JB.]

Farmerjon, just to paint a picture to conceptualize from, here's how the engine braking power lines up in each tranmission gear from most to least in the 4th gen. 3rd gen is no doubt a little different, but you get the point.

Low range
High range


1
2
3 - 1 Same
4
2
5 - Not available
3
4
5

 

[tre9er]

Brian2Sun is dead on.

Just to add some confusion to the mix, I can actually put my 02 in 2wd low range. it has to with my trac off switch. When I hit the switch, the ECU thinks it is already in 4wd so it will not engage the front tires. It is pointless but can be fun at times when I want to the challenge of 2wd but want to keep things cool with low range.

Question is, can you use trac off while already in 4WD and the front stays locked in? Cause that would piss me off if I can't disable vsc/trac (I also have wired the switch) in 4wd...

 

[twitchee2]

Question is, can you use trac off while already in 4WD and the front stays locked in? Cause that would piss me off if I can't disable vsc/trac (I also have wired the switch) in 4wd...

yes, i just cannot disengage until trac if back on. It just makes it think its already in 4 low with the centerdiff locked so it doesnt do anything.