Pin 7 mod in snow and ice (no lockers)? (1 Viewer)

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All the 7 pin mod does is overcome the fact that Toyota removed this function in high range, presumably due to the AWD functionality in high being considered enough.

Manual control of CDL is great to have, you can stay in AWD low range for tight offroad switchbacks, but really it just adds back in something Toyota removed from a dash button perspective. The “multi-mode” t-cases found in certain 3rd Gen 4Runners and 1st Gen Sequoias have separate engagement for AWD and 4WD (locked CDL), and outside of not having 2WD, you have that as well.

I use high range CDL all the time in winter as it is more stable than AWD in some variable conditions like changing lanes at speed with more snow depth between lanes. Just play around with it - only “rule” is you’ll get binding in tight corners with CDL on I’m high traction conditions.

These cases are gear driven and a lot more tolerant use on say dry pavement than chain driven cases in my experience, but the idea that diff locks are “bad” in snow is still going strong because people drove CJ7’s 35 years ago and still say so on the internet.

I run AWD until either I’m losing traction in deep snow or AWD is starting to feel squirrelly at speed, and then CDL is on.
hey man.

trying to keep up here and i do realize i am asking a lot of different types of questions. i am just trying to put it al together.

pin 7 allows me to run “4 high” with the CDL locked? and also to run “4 Low” without the CDL locked?

i think i am getting tripped up because i don’t really understand what “4 Hi” or “4 Low” actually means.

i mean in my taco i manually lock the front hubs which - well i guess literally ties the front wheels to the (already) spinning front driveshaft? or something or other?

what is the 2H here exactly?(!)

C54C185C-36CA-406C-8E64-1C030A5C3D4D.jpeg
 
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^^^^

I like this ability too. In fact used it yesterday and today. In the conditions the OP posted (looks like the dry, powder snow most of Texas got the other day) he should be able to navigate that hill with the CDL locked or unlocked, but locked would be easier. I put about 50 miles on mine yesterday in the same type of snow up and down a lot hills. Sometimes with CDL on...other times not, but in high range the entire time.

Just shifted to a lower gear with the transmission when going down hills to use 'engine braking' to slow down instead of the vehicle brakes.

There are also times when I shift the Tcase into low range with the CDL unlocked when moving heavy things around here on the ranch. So to me...having the CDL switch AND the 7 pin 'mod' is the way to go...since it gives you complete control.

In the next day or so....we are supposed get ICE and that's whole 'nother ball game.
hey man. can you please help me with the difference between putting the transfer case in Low and my shifting the transmission into 2 or Low?
i don’t quite get this.
on a motorcycle or on a stick shift truck i guess 2 would be - well would it be second? and Low would be like first?
and it sort of gives me more torque but less wheel spin?
what is putting it in Low at the transfer case ries the CDL unlocked doing again please?
 
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All the 7 pin mod does is overcome the fact that Toyota removed this function in high range, presumably due to the AWD functionality in high being considered enough.

Manual control of CDL is great to have, you can stay in AWD low range for tight offroad switchbacks, but really it just adds back in something Toyota removed from a dash button perspective. The “multi-mode” t-cases found in certain 3rd Gen 4Runners and 1st Gen Sequoias have separate engagement for AWD and 4WD (locked CDL), and outside of not having 2WD, you have that as well.

I use high range CDL all the time in winter as it is more stable than AWD in some variable conditions like changing lanes at speed with more snow depth between lanes. Just play around with it - only “rule” is you’ll get binding in tight corners with CDL on I’m high traction conditions.

These cases are gear driven and a lot more tolerant use on say dry pavement than chain driven cases in my experience, but the idea that diff locks are “bad” in snow is still going strong because people drove CJ7’s 35 years ago and still say so on the internet.

I run AWD until either I’m losing traction in deep snow or AWD is starting to feel squirrelly at speed, and then CDL is on.

can you hope me with this bit?

“I use high range CDL all the time in winter as it is more stable than AWD in some variable conditions like changing lanes at speed with more snow depth between lanes.”

you are clicking the CDL on at speed and this is giving you front and rear drive shafts locked together and it sort of gives you a more solid - kind of rigid - base?
 
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Unlike your Tacoma, the 80 is full-time 4WD. That's why it has the CDL and viscous coupler. The VC provides the slip that you don't get when on the road in a part-time 4WD if you shift the Tacoma TC from 2 High to 4 High. There is no equivalent to 2 High in the 80 series TC, which may be where this confusion starts.

Of course, if you got stuck by slippery stuff under one end of the truck, then you'd hopelesslly spin your wheels there and the truck doesn't go. That's where the CDL comes in. It does what your Tacoma does where you switch into either 4 High or 4 Low and it locks the drivetrain together front and rear, splitting the torque 50/50 front to rear. But you also have the VC in the 80 which can split the torque a variable amount between the front and rear wheels. Which you want to use on snow and ice varies, Just be careful until you're comfortable with the CDL locked. With the CDL locked, it operates equivalent to the 50/50 split of of the part-time case.
lots of questions. sorry.

what is the difference between H2, H4 and Low 4 in the tacoma again please? maybe i should start there..
 
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Think of it this way..... on the transfer case you are shifting from high RANGE to low RANGE, On the transmission you are shifting gears within that RANGE.

When in low RANGE you'll notice that torque has increased significantly (in every gear) however speed is decreased, which is the whole point of gear reduction.

The transfer case in the tacoma does basically the same thing as it does in the cruiser, the only difference is that the cruiser is driving all 4 wheels all of the time (all wheel drive) so there is no H2 option. H2 in your tacoma removes power to the front wheels and only powers the rears.

Sounds like this evening you'll be spending some time on youtube learning about gear reduction and transfer cases :)
 

Bludozer

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hey man.

trying to keep up here and i do realize i am asking a lot of different types of questions. i am just trying to put it al together.

pin 7 allows me to run “4 high” with the CDL locked? and also to run “4 Low” without the CDL locked?

i think i am getting tripped up because i don’t really understand what “4 Hi” or “4 Low” actually means.

i mean in my taco i manually lock the front hubs which - well i guess literally ties the front wheels to the (already) spinning front driveshaft? or something or other?

what is the 2H here exactly?(!)

View attachment 2587347
hey man. can you please help me with the difference between putting the transfer case in Low and my shifting the transmission into 2 or Low?
i don’t quite get this.
on a motorcycle or on a stick shift truck i guess 2 would be - well would it be second? and Low would be like first?
and it sort of gives me more torque but less wheel spin?
what is putting it in Low at the transfer case ries the CDL unlocked doing again please?
can you hope me with this bit?

“I use high range CDL all the time in winter as it is more stable than AWD in some variable conditions like changing lanes at speed with more snow depth between lanes.”

you are clicking the CDL on at speed and this is giving you front and rear drive shafts locked together and it sort of gives you a more solid - kind of rigid - base?
lots of questions. sorry.

what is the difference between H2, H4 and Low 4 in the tacoma again please? maybe i should start there..


Is this you?


baby_willingly_eating_from_spoon_-5oopx_with_outline_4.jpg


Good lord man, I just typed "how a transfer case works" into google - maybe start there with something like this:


 

flintknapper

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for what it’s worth that’s ice under there. i mean i am not totally asking this question just to get up that hill but i realized i don’t understand a couple things so figured to ask and use it as sort of an example...

Oh I know....everyone got sleet/ice BEFORE the snow fell. And then with enough traffic 'powder snow' becomes 'hard pack' which is just one step away from ice. We're all driving on the same thing. But I've put about 75 miles total (today and yesterday) in just what you posted and as long as you don't dig down to the ice....a bone stock Land Cruiser (with decent tires) will walk right up that.

I understand you are searching for answers and applaud you for that.

We can't always recommend the 'best' gear (transfer case or transmission) for you to use because conditions vary so much. But we can help provide you with certain 'knowledge tools' that will aid you in making the decisions.

At times it sounds confusing because some of the folks responding also have lockers/traction aiding devices in their differentials and that alone can dictate when (or when not) you might choose a certain combination.

But to keep it simple:

Your transmission has a range/set of gears that is separate from the Transfer Case. You have in ascending order Low, 2nd and Drive (and in some cases Overdrive). You ALWAYS have these gears to work with. As you are aware (when your transmission is in drive) the transmission automatically up-shifts to each higher gear as you gain speed and apply throttle. You can probably 'feel' it shifting through the gears.

So you know how that works. Your Transfer Case has two sets of gears. One provides 'high range' (what you normally drive in) and the other (if you select it) 'low range' which is typically used off-road for slower speeds.

The gears in your transmission remain unaffected...they are always the same ratio and will still shift from low to second then 3rd/drive (if you start with the trans in drive). BUT....in low range you have a mechanical advantage (higher gearing). Meaning your transfer case gears (in low range) are turning more times (per one revolution of the driveshafts than when in high range.

An analogy might be as with a Mountain Bike where you shift down into its lowest 'gear'. You are peddling like a MoFo (your feet are the transfer case) but it doesn't take much effort and the torque to rear wheel is greater.

As for your CDL (Center Diff Lock) that simply locks the front and rear outputs together and forces them to turn at exactly the same speed (no differentiation) so the torque from the engine is evenly split front to rear. This can be good or not so good depending on your needs and the situation.

But with the CDL button and the Pin 7 'mod' YOU can choose to engage it or disengage at any time, any speed, just about any situation.

There is more to know about your transmission....such as manually shifting to a lower gear, when the transmission will 'hold' that gear and when it won't. When any of that might be appropriate. Best thing to do at first....is simply find a place you can off-road, put your Tcase in low range and experience what it does compared to high range and all of this will begin to make sense to you.

One last thing you asked about. 2nd gear 'start' allows your transmission to start out in 2nd gear (less torque) rather than the lower 1st/low gear to help avoid spinning your tires on surfaces that have low traction (ice, hard pack snow, etc). That is all it does.
 

Nframe

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Main advantage of the Pin 7 mod is it allows you to be in 4 low without the CDL locking front and rear together.
Good for some applications. If I'm running in snow I'd rather be locked.
(or that's my take on it anyway)
 
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All these post and no one has said it yet....A Tacoma does not have a CDL option. It has 2hi, 4hi, 4low, No VC to engage or dis-engage. NOT an option on a Tacoma.

Sorry to be the one. Now if you want to by-pass the computer and engage the rear locker in high range or 2wd, that is another story.
 

flintknapper

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All these post and no one has said it yet....A Tacoma does not have a CDL option. It has 2hi, 4hi, 4low, No VC to engage or dis-engage. NOT an option on a Tacoma.

Sorry to be the one. Now if you want to by-pass the computer and engage the rear locker in high range or 2wd, that is another story.


I think the main concern is with his 80 Series and he just brought the 'Tacoma' into the mix. So two separate discussions going on in one thread.
 
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All these post and no one has said it yet....A Tacoma does not have a CDL option. It has 2hi, 4hi, 4low, No VC to engage or dis-engage. NOT an option on a Tacoma.

Sorry to be the one. Now if you want to by-pass the computer and engage the rear locker in high range or 2wd, that is another story.

Explain the difference between locking a Taco t-case in 4Hi and locking an 80 case in 4Hi with the switch that the 7-pin mod provides.

Please.
 

flintknapper

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Explain the difference between locking a Taco t-case in 4Hi and locking an 80 case in 4Hi with the switch that the 7-pin mod provides.

Please.

End result is the same. Both Tcases are in high range, both have the output shafts turning at the same speed.

With the Taco you (traditional Tcase) you just shift into high range. With the 80 series (pin 7 mod AND CDL switch) you select high range and punch the CDL button.

Different ways of getting to the same destination.
 
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Main advantage of the Pin 7 mod is it allows you to be in 4 low without the CDL locking front and rear together.
Good for some applications. If I'm running in snow I'd rather be locked.
(or that's my take on it anyway)

I’d say the main advantage is you can lock in 4Hi. Mechanical AWD is not sufficient in a lot of winter driving cases where low range is not feasible.
AWD low is nice to have, but a tire can always scrub offroad.
 
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End result is the same. Both Tcases are in high range, both have the output shafts turning at the same speed.

With the Taco you (traditional Tcase) you just shift into high range. With the 80 series (pin 7 mod AND CDL switch) you select high range and punch the CDL button.

Different ways of getting to the same destination.

I wanted him to explain the difference between 4Hi (a locked center) and CDL (a locked center).

Don’t go spoiling my fun.
 
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can you hope me with this bit?

“I use high range CDL all the time in winter as it is more stable than AWD in some variable conditions like changing lanes at speed with more snow depth between lanes.”

you are clicking the CDL on at speed and this is giving you front and rear drive shafts locked together and it sort of gives you a more solid - kind of rigid - base?

A locked center diff means all the power can’t go to the front or rear when the other is slipping.

The key is to understand a mechanical differential. When you drive around a corner, the outside wheel has to travel further than the inside wheel, so it has to spin faster. The differential sends more power mechanically to the wheel that is spinning faster, which is what you want for dry road driving, and it allows “differentiated” speed between the two tires.

If you have a center differential, this is then what is called “all wheel drive” and if you can lock that differential, you then have “four wheel drive”.

The problem with “open” differentials is they send the power to the fastest spinning wheel, and in low traction situations, that means the wheel that has low or no traction gets the torque, and you get stuck. AWD can send all of the power to one wheel (that has no traction). Lock the transfer case (4Hi) and you have to lose traction at a wheel on each axle.

Lock the axle differentials (if you have “lockers”) and you have to lose traction at all four wheels.

Modern electronic traction control uses independent four wheel braking to stop a wheel from spinning so torque is distributed back to the other side. But brakes can only get you so far if all wheels have traction. I took this vid today - excellent example.


The issue with “locking” a differential is it can no longer differentiate speed. That’s why if you lock your transfer case and force equal rotation of both driveshafts, you will have problems of tight radius turns on dry pavement. AWD overcomes this as torque can be biased between the axles. That bias, however, can lead to unstable feeling vs locking the center.

Your Taco doesn’t have a differential in the T-case so it is either 2wd (unlocked) or 4wd (locked). AWD is great in variable winter conditions where you don’t want to be locked but you so want more than 2wd.

So it’s nice to have options. Play around with them next time it snows.
 
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I wanted him to explain the difference between 4Hi (a locked center) and CDL (a locked center).

Don’t go spoiling my fun.
Ok, I will bite. Less moving parts. No electronics to fail, simple, move a lever and it is in 4wd, no computer, no switch, etc. You have already explained the benefits of AWD. The OP showed pics of a shift lever from a Tacoma, not a 80. It sounded like he thinks the Tacoma has a CDL feature. Unless I am reading it wrong I though he was asking about his Tacoma not an 80. See post #1, 2, 16, 25...he keeps asking about his Tacoma???
 
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Nframe

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I’d say the main advantage is you can lock in 4Hi. Mechanical AWD is not sufficient in a lot of winter driving cases where low range is not feasible.
AWD low is nice to have, but a tire can always scrub offroad.
I have the CDL switch, but haven't done the Pin7 mod.
Doesn't that allow me to lock front and rear in 4 Hi?
 
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I have the CDL switch, but haven't done the Pin7 mod.
Doesn't that allow me to lock front and rear in 4 Hi?
Pin 7 mod gives you full control of the CDL. It wont lock in low unless you have CDL ON. The front and rear lockers wont engage until the CDL is locked (Hi or Lo). You can do that without the Pin 7 mod. Put another way... with just the CDL switch ON (and no Pin 7 mod) you can lock front and rear in Hi....you always could in Lo (with or w/o CDL switch). With the Pin 7 mod you wont be able to lock the front and rear in Hi or Lo unless the CDL is ON. The main purpose of the Pin 7 mod is an unlocked center diff in Lo...this gives you low gearing without turning restriction. Think narrow trails and boat launches.
Experts: Did I get this right?
 
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Pin 7 mod gives you full control of the CDL. It wont lock in low unless you have CDL ON. The front and rear lockers wont engage until the CDL is locked (Hi or Lo). You can do that without the Pin 7 mod. Put another way... with just the CDL switch ON (and no Pin 7 mod) you can lock front and rear in Hi....you always could in Lo (with or w/o CDL switch). With the Pin 7 mod you wont be able to lock the front and rear in Hi or Lo unless the CDL is ON. The main purpose of the Pin 7 mod is an unlocked center diff in Lo...this gives you low gearing without turning restriction. Think narrow trails and boat launches.
Experts: Did I get this right?
That was needlessly complicated:
CDL switch allows you to lock and unlock the center diff in Hi
Pin 7 mod and CDL switch allows you to lock and unlock the center diff in Lo
Front and rear lockers wont engage unless the center diff is locked.
 
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