yeppers
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
No,
So, the cruiser senses the slippage and runs power to the front wheels regardless of wether or not I have the button pushed.
there is no magic part of your truck wich senses the slippage and transfers more power anywhere. the transfer case will not care a bit wether the front wheels are going or not. the center diff lock merely makes it so the front wheels can not slip at a rate higher than the rears.
SO.
You are driving down the strred and the banana truck wipes out. the front wheels slip. the rear wheels will still turn but not enough to get you going. you push your magic cdl button and the front and rear drive shafts will turn at the same rate. You still have the differentials that have to be overcome before you can get to the grocery store for whip cream.
Dave
So, the cruiser senses the slippage and runs power to the front wheels regardless of wether or not I have the button pushed.
there is no magic part of your truck wich senses the slippage and transfers more power anywhere. the transfer case will not care a bit wether the front wheels are going or not. the center diff lock merely makes it so the front wheels can not slip at a rate higher than the rears.
SO.
You are driving down the strred and the banana truck wipes out. the front wheels slip. the rear wheels will still turn but not enough to get you going. you push your magic cdl button and the front and rear drive shafts will turn at the same rate. You still have the differentials that have to be overcome before you can get to the grocery store for whip cream.
Dave
Doc,
if you have an AWD rig like the 80, I believe that power goes all the time to the front, not just the rear as you suggested. Now, if the front were to slip fully, then yes, you would get basically no traction front or rear unless the center diff is locked.
Basically, the center diff is like the front or rear, if you lose one half you lose both without locker.
[Not too sure about the VC role in this front slip / no traction without locker scheme, though, I'll admit]
E
if you have an AWD rig like the 80, I believe that power goes all the time to the front, not just the rear as you suggested. Now, if the front were to slip fully, then yes, you would get basically no traction front or rear unless the center diff is locked.
Basically, the center diff is like the front or rear, if you lose one half you lose both without locker.
[Not too sure about the VC role in this front slip / no traction without locker scheme, though, I'll admit]
E
[quote author=Montana Cruiser link=board=2;threadid=16332;start=msg156970#msg156970 date=1084549402]
Soooooo, is this the CDL switch we are talking about? This is a pick of my dash, looking at the switch in the upper left. Mines a 97' does this mean the PO installed this? Also, can you have the switch and no Pin 7 Mod? I have tried pushing it and it lights up on the dash ???[/quote]
EDIT OK I must be slow like 20 people posted wile I was writing this :
AFIK the 97 did not come from the factory with the CDL switch so it must be a PO install, you could have the switch without the pin 7 mod,
with the CDL switch unlocked:
if the center diff locks when you shift into low then you do not have the pin 7 mod, and your plug on the transfer case is hooked up, in this case all the switch allows you to do is lock/unlock the center wile in high, you loose control of it in low
if it does not lock the center when shifting into low you either have the pin 7 mod or the transfer case plug is unpluged (pre pin 7 method)
if you have normal low range shift points (shifts at a higher RPM) wile in low but the center diff does not lock when shifting into low you have the pin 7 mod and the plug is hooked up, you have full control of the center diff in any range with proper shift points for that range
if you have the Pin 7 mod you will have to lock the center with the switch to lock the front and rear lockers
Soooooo, is this the CDL switch we are talking about? This is a pick of my dash, looking at the switch in the upper left. Mines a 97' does this mean the PO installed this? Also, can you have the switch and no Pin 7 Mod? I have tried pushing it and it lights up on the dash ???[/quote]
EDIT OK I must be slow like 20 people posted wile I was writing this :
AFIK the 97 did not come from the factory with the CDL switch so it must be a PO install, you could have the switch without the pin 7 mod,
with the CDL switch unlocked:
if the center diff locks when you shift into low then you do not have the pin 7 mod, and your plug on the transfer case is hooked up, in this case all the switch allows you to do is lock/unlock the center wile in high, you loose control of it in low
if it does not lock the center when shifting into low you either have the pin 7 mod or the transfer case plug is unpluged (pre pin 7 method)
if you have normal low range shift points (shifts at a higher RPM) wile in low but the center diff does not lock when shifting into low you have the pin 7 mod and the plug is hooked up, you have full control of the center diff in any range with proper shift points for that range
if you have the Pin 7 mod you will have to lock the center with the switch to lock the front and rear lockers
As far as the power to the front wheel thing, it all depends. On the earlier transfer cases you had power going everywhere and if you lost traction on one wheel you where stuck. On later models with ABS, there is a VC in there. If you loose traction on one wheel the VC will lock up and transfer drive to the other axle. I think this is why the earlier trucks had the CDL switch and the later did not as the later transfer cases where automatic in a sense.
How do the factory front and rear diff locks fit in to this? Can I lock the front and rear diffs without locking the center diff? (IE it has to be in low range unless I buy this switch..)
If I have the center diff locked via the switch, and it's still in high range, can I lock and unlock the front and rear diffs as well?
If I have the center diff locked via the switch, and it's still in high range, can I lock and unlock the front and rear diffs as well?
Ok doc
short and sweet here.
Rick is correct on the 91-92 trucks tehre is no vc just speder gears. so in high range with cdl unlocked you lose one wheel and you are not going anywhere. teh addition of the vc coupler in the transfer case made it so some power would be sent to the rears regardless of what the front was doing. there is no variable sending of torque to slipping wheels ever.
So by you rsig you have f&r diff locks so going back to the banana truck...........
so you hit the bananas you are in high just normal driving. the front wheels start to slip, the front driveline gets a reduction in power. the rears try to compensate for the slippage as teh torque has to go somewhere but can not. So you push the cdl button, Now your front and rear drivelines and trunign at the same rate. exactly like a normal 4wd truck in 4w high. you still dont have enough traction for the whip cream. SO you shift to low range. Still no dice and you are getting hungry. SO you engage the rear locker only, Now understand unless you do some serious modding to the wiring you can not lock the diffs unless you are in low. still not enough so you engage the front end lockers with the rear end lockers you finally hae enough grunt to get to teh grocery store as your cdl has gaurenteed even bias between teh front and rear drive lines. you diff lockers make it so you can make sure that power is split evenly to either wheel.
does that make more sense?????
Dave
short and sweet here.
Rick is correct on the 91-92 trucks tehre is no vc just speder gears. so in high range with cdl unlocked you lose one wheel and you are not going anywhere. teh addition of the vc coupler in the transfer case made it so some power would be sent to the rears regardless of what the front was doing. there is no variable sending of torque to slipping wheels ever.
So by you rsig you have f&r diff locks so going back to the banana truck...........
so you hit the bananas you are in high just normal driving. the front wheels start to slip, the front driveline gets a reduction in power. the rears try to compensate for the slippage as teh torque has to go somewhere but can not. So you push the cdl button, Now your front and rear drivelines and trunign at the same rate. exactly like a normal 4wd truck in 4w high. you still dont have enough traction for the whip cream. SO you shift to low range. Still no dice and you are getting hungry. SO you engage the rear locker only, Now understand unless you do some serious modding to the wiring you can not lock the diffs unless you are in low. still not enough so you engage the front end lockers with the rear end lockers you finally hae enough grunt to get to teh grocery store as your cdl has gaurenteed even bias between teh front and rear drive lines. you diff lockers make it so you can make sure that power is split evenly to either wheel.
does that make more sense?????
Dave
Doc,
Read the Diffs for Dummies page. The link has been posted a hundred times.
-B-
Read the Diffs for Dummies page. The link has been posted a hundred times.
-B-
Doc, Daves pretty much got you hooked up, if you can get through the grammer 
.
Final notes so you can put it all together.
Without installing a CDL switch, you've currently got two options:
1) High range normal everyday driving mode (center differential is unlocked), and 2) Low range (different gear partern than High range) which automatically locks the center differential.
With CDL switch you add one more option: you can drive in high range with the center differential locked. So maybe if you're on a snow run or on some loose gravel roads, you can get some extra traction without having to ride around at 10 mph.
With Pin 7 mod you add one more option: you can drive in low range, without the center differential locked. So if you're pulling a boat out of the water and want the lower gear pattern, but don't want the center diff. locked sense you're on asphalt for fear of F'ing up something in your driveline, you can do that.
Capeesh?? (sp??)
Rookie2
.Final notes so you can put it all together.
Without installing a CDL switch, you've currently got two options:
1) High range normal everyday driving mode (center differential is unlocked), and 2) Low range (different gear partern than High range) which automatically locks the center differential.
With CDL switch you add one more option: you can drive in high range with the center differential locked. So maybe if you're on a snow run or on some loose gravel roads, you can get some extra traction without having to ride around at 10 mph.
With Pin 7 mod you add one more option: you can drive in low range, without the center differential locked. So if you're pulling a boat out of the water and want the lower gear pattern, but don't want the center diff. locked sense you're on asphalt for fear of F'ing up something in your driveline, you can do that.
Capeesh?? (sp??)
Rookie2
Rookie2,
The privilege of harassing fAvE on his spelling and grammar is reserved for the hall monitor.
-B-
The privilege of harassing fAvE on his spelling and grammar is reserved for the hall monitor.
-B-
Crap, I think I actually get it too! The best part is that I already have the CDL switch, and its sounds like I have the PIN 7 Mod as well 
This was a great purchase and it frees up some $$ for other "important" things like getting rid of the frickin' Gold Package :
Thanks for the detailed descriptions guys, now that I get it maybe I can put it to good use soon!
The best part is that I already have the CDL switch, and its sounds like I have the PIN 7 Mod as well This was a great purchase and it frees up some $$ for other "important" things like getting rid of the frickin' Gold Package :Thanks for the detailed descriptions guys, now that I get it maybe I can put it to good use soon!
[quote author=Phaedrus link=board=2;threadid=16332;start=msg157052#msg157052 date=1084554080]
So you push the cdl button, , Now understand unless you do some serious modding to the wiring you can not lock the diffs unless you are in low.
Dave
[/quote]
With the cdl engaged in Hi, the frt. and rear lockers will lock.
So you push the cdl button, , Now understand unless you do some serious modding to the wiring you can not lock the diffs unless you are in low.
Dave
[/quote]
With the cdl engaged in Hi, the frt. and rear lockers will lock.
I did not know that one lokd,
thaks for the clarification and a big ole STFU!!!!!! to beo and rookie, be happy you grammar nazis I reread and fixed my typos at least................
fAvE
thaks for the clarification and a big ole STFU!!!!!! to beo and rookie, be happy you grammar nazis I reread and fixed my typos at least................
fAvE
MoJ
Moderator
[quote author=Montana Cruiser link=board=2;threadid=16332;start=msg156998#msg156998 date=1084550534]
Ok, so I went out and shifted from high to nuetral and a red light on the dash "A/T P" lit up and then shifted into Low and that light went out and nothing else lit up until I pushed the CDL switch and then the sideways "H" symbol lit up. So what does that mean? I am guessing I have the Pin 7 as well?
[/quote]
It appears so.
Ok, so I went out and shifted from high to nuetral and a red light on the dash "A/T P" lit up and then shifted into Low and that light went out and nothing else lit up until I pushed the CDL switch and then the sideways "H" symbol lit up. So what does that mean? I am guessing I have the Pin 7 as well?
[/quote]
It appears so.
[quote author=Phaedrus link=board=2;threadid=16332;start=msg157126#msg157126 date=1084560003]
I did not know that one lokd,
thaks for the clarification and a big ole STFU!!!!!! to beo and rookie, be happy you grammar nazis I reread and fixed my typos at least................
fAvE
[/quote]
No worries Dave.
Sorry for the misunderstanding. I'd hate to be ex-spelled for overstepping my bounds here.
Rookie2
I did not know that one lokd,
thaks for the clarification and a big ole STFU!!!!!! to beo and rookie, be happy you grammar nazis I reread and fixed my typos at least................
fAvE
[/quote]
No worries Dave.
Sorry for the misunderstanding. I'd hate to be ex-spelled for overstepping my bounds here.
Rookie2
no sweat,
and btw grammer is the last name of a pompous actor,
grammar is what I need help with.
Dave
and btw grammer is the last name of a pompous actor,
grammar is what I need help with.
Dave
[quote author=Montana Cruiser link=board=2;threadid=16332;start=msg157098#msg157098 date=1084557892]
The best part is that I already have the CDL switch, and its sounds like I have the PIN 7 Mod as well[/quote]
Well you might have another mod done, but not the pin7 necessarily. Adding the CDL switch lets you engauge the CDL in highrange, but the factory setup still applies in Low Range, where putting it in Low Range the CDL is locked automatically.
If you disconnect a electrical connector on the transfercase then the automatic part is gone. So the CDL only locks when you tell it to, never automatically.
The difference between having that t/c electrical connector missing and the pin-7 mod is vague. I *think* the difference is with the electrical connector missing (like mine is) when you are in Low Range the computer does not know that you are, so the tranny shifts as if in high-range. You can manually control the CDL but you can never get to the designed Low Range tranny shift points.
However I *think* by doing the pin7 mod instead of disconnecting the electrical connector on the transfercase, then if you put the t/c in Low Range the computer knows it and uses the correct tranny shift points for Low Range. I don't know if the pin7 mod alone still automatically engauges the CDL in Low Range or not. We did this mod (ok I watched) to Mark Huxley's '93, and then drove it around on some dirt piles, neither of us could really tell if it did anything at all, maybe slightly, but very hard to tell the difference in shift pattern. Other might say it was very obvious, but with our little test it wasn't obvious at all, so IMO, not worth the effort.
I *think* (wow, alot I'm not sure of huh :-\) when the tranny uses the Low Range shift points it's sposeto shift at a lower rpm, versus the High Range shift points where it would shift at a higher rpm. However, 99% of the time I'm offroad I shift all manually anyway, so nothing gained IMO.
The best part is that I already have the CDL switch, and its sounds like I have the PIN 7 Mod as well[/quote]
Well you might have another mod done, but not the pin7 necessarily. Adding the CDL switch lets you engauge the CDL in highrange, but the factory setup still applies in Low Range, where putting it in Low Range the CDL is locked automatically.
If you disconnect a electrical connector on the transfercase then the automatic part is gone. So the CDL only locks when you tell it to, never automatically.
The difference between having that t/c electrical connector missing and the pin-7 mod is vague. I *think* the difference is with the electrical connector missing (like mine is) when you are in Low Range the computer does not know that you are, so the tranny shifts as if in high-range. You can manually control the CDL but you can never get to the designed Low Range tranny shift points.
However I *think* by doing the pin7 mod instead of disconnecting the electrical connector on the transfercase, then if you put the t/c in Low Range the computer knows it and uses the correct tranny shift points for Low Range. I don't know if the pin7 mod alone still automatically engauges the CDL in Low Range or not. We did this mod (ok I watched) to Mark Huxley's '93, and then drove it around on some dirt piles, neither of us could really tell if it did anything at all, maybe slightly, but very hard to tell the difference in shift pattern. Other might say it was very obvious, but with our little test it wasn't obvious at all, so IMO, not worth the effort.
I *think* (wow, alot I'm not sure of huh :-\) when the tranny uses the Low Range shift points it's sposeto shift at a lower rpm, versus the High Range shift points where it would shift at a higher rpm. However, 99% of the time I'm offroad I shift all manually anyway, so nothing gained IMO.
