Just FYI: LQ9's and 1/2ton transfer cases dont get along

[treyZ28]

I've had it for 2 weeks. Had to try 4 Lo. 3/4 throttle dip of the throttle = tires spinning, truck jumping and something breaking. I tapped the throttle.

I figured the cold mud terrains would spin on the cold road before anything snapped. Nope. Rice Crispies!

2wd sounds fine. 4x4 (manual t-case btw) sounds weird. Im thinking i popped a tooth of the ring and pinion.

[FryZ71]

Not for nothing, but why would you have it in 4Lo on pavement?

[CHEV4LIFE]

well good Fvckin job.............. man that sucks, hope you can get'er fixed up

[oldred95]

Aren't you the guy that through the rod on the 4.8 and did the 6.0 swap? If so you got that done pretty damn fast. And for future reference 4wd and pavement dont mix. Don't know if it will fit but I read the HD or maybe it was the Dmax transfer cases are extremely strong, like tested to 1200 ft lbs. or something like that.

[Luke2kZ71]

i broke an autotrac case with my stock 5.3 ... dont feel too bad :LOL:

[CHEV4LIFE]

why doesnt 4x4 like pavement?

[Frankenbiker]

pavement use requires a center differential, which GM trucks don't generally have. The axles (as well as the wheels) turn at different speeds in a turn.

-blaine

[MSF]

There aren't center differentials in 4WDs like there are in AWDs, therefore not allowing the front & rear axles to turn at different speeds, and when there is too much traction & parts turning at different rates... boom.

[Pauly]

As long as the truck is moving forward the fron and the rear axles are turning the same speed, when cornering its the left and the right axes that turn at a different speed. The newer 4wd transfer cases are PWM(pulse width modulated) and dont experience the driveline widup that used to occur in the older 4x4's. The front and rear driveshafts actaully spin at slightly different speeds as the PWM clutches are continuously slipping(by design) and never fully lock up(kind of like some 4l60e's torque converter clutches, there always about 10-70 rpm difference between th edriven and driving parts, sounds scaryy but that what they do)

The only reason he busted something is because of the crazy amount of torque he put through the drivetrain. 4hi is 1 thing but when in 4 low, the torque loads are twice as high. The lower the gearing, the more the engine torque is multiplied. That t-case and diffs are only meant for a 5.3, certauinly not a 6.0 in 4wd low.. The new 6.0 l 2wd trucks use a 14 bolt rear to tame the 6.0 reliably, the SS trucks use AWD but dont have the 2:1 gearing of the 4ed ow transfer cases.
You arent driving a GMC Syclone or Typhoon, they can light up the tires with their AWD systems and dont need the 2:1 gear reduction to do it. I understand why you did it, but I doubt you should do it again. I wish I had your money.

Lets say that his engine is making 400 lb ft of torque at the engine.
With the 60e in 1st that is multiplied by 3.06 which is 1224 lb ft now, now it goes thru the tranfer case which is now in 4 lo, now that torque gets multiplied by 2(most common low range GM transfer cases are 2:1 and 1:1 in 4hi) so now we are at 4,448 lb ft of torque. Now it goes into the differential, lets say the difs have 3.73 gears in them, now we are at 9,131 lb ft of torque at the axles.
trust me these torque values were much higher at the time because I didnt even figure in the torque multiplication of the torque converter.

4wd on pavement is fine with todays 4wd trucks, look at parish, he is running 10's in 4wd with a monster turbo. he is also running a 3/4 ton transfer case, which has double the torque rating of the 1/2 ton version.

I bet you had the poor truck matted when this happend, 3/4 throttle my ass. I had a buddy who took out his brand new 1998 Vortec 350 Z71 and did the same thing, the Vortec 350 puts out more torque at 2000 rpm than the 6.0 does. he had 3.73's and only 700 kilometers(seven hundred kilometers) on his trcuk when he did it. I almost crapped my pants when he did it, I told him not too. he put her in 4lo on the pavement and matted the thing, the tires smoked and teh truck bounced, the thing shfted into 2nd so fast and was bouncing off of revlimiter.

He didnt break anything but, what a horrible thing to do to a vehicle, esp with that many mile on it, nothing is even close to being broken in yet, but oh well it was fun.

take care man, I hope you get her fixed ok.. Maybe a 3/4 ton t-case. I remember the old Blazers withthe 4hi, 4lo, 2 hi and 2lo tranfer cases, boy did those things scoot in 2 low, talk about short gears, wow.

pauly

[treyZ28]

Aren't you the guy that through the rod on the 4.8 and did the 6.0 swap? If so you got that done pretty damn fast. And for future reference 4wd and pavement dont mix. Don't know if it will fit but I read the HD or maybe it was the Dmax transfer cases are extremely strong, like tested to 1200 ft lbs. or something like that.

yup. 4 days. would have been 3 if a jack didn't bust and one other stupid mistake (missed a bolt on the bell housing- after a 12 hour day, stupid mistakes are easy to make)

[treyZ28]

As long as the truck is moving forward the fron and the rear axles are turning the same speed, when cornering its the left and the right axes that turn at a different speed. The newer 4wd transfer cases are PWM(pulse width modulated) and dont experience the driveline widup that used to occur in the older 4x4's. The front and rear driveshafts actaully spin at slightly different speeds as the PWM clutches are continuously slipping(by design) and never fully lock up(kind of like some 4l60e's torque converter clutches, there always about 10-70 rpm difference between th edriven and driving parts, sounds scaryy but that what they do)

The only reason he busted something is because of the crazy amount of torque he put through the drivetrain. 4hi is 1 thing but when in 4 low, the torque loads are twice as high. The lower the gearing, the more the engine torque is multiplied. That t-case and diffs are only meant for a 5.3, certauinly not a 6.0 in 4wd low.. The new 6.0 l 2wd trucks use a 14 bolt rear to tame the 6.0 reliably, the SS trucks use AWD but dont have the 2:1 gearing of the 4ed ow transfer cases.
You arent driving a GMC Syclone or Typhoon, they can light up the tires with their AWD systems and dont need the 2:1 gear reduction to do it. I understand why you did it, but I doubt you should do it again. I wish I had your money.

Lets say that his engine is making 400 lb ft of torque at the engine.
With the 60e in 1st that is multiplied by 3.06 which is 1224 lb ft now, now it goes thru the tranfer case which is now in 4 lo, now that torque gets multiplied by 2(most common low range GM transfer cases are 2:1 and 1:1 in 4hi) so now we are at 4,448 lb ft of torque. Now it goes into the differential, lets say the difs have 3.73 gears in them, now we are at 9,131 lb ft of torque at the axles.
trust me these torque values were much higher at the time because I didnt even figure in the torque multiplication of the torque converter.

4wd on pavement is fine with todays 4wd trucks, look at parish, he is running 10's in 4wd with a monster turbo. he is also running a 3/4 ton transfer case, which has double the torque rating of the 1/2 ton version.

I bet you had the poor truck matted when this happend, 3/4 throttle my ass. I had a buddy who took out his brand new 1998 Vortec 350 Z71 and did the same thing, the Vortec 350 puts out more torque at 2000 rpm than the 6.0 does. he had 3.73's and only 700 kilometers(seven hundred kilometers) on his trcuk when he did it. I almost crapped my pants when he did it, I told him not too. he put her in 4lo on the pavement and matted the thing, the tires smoked and teh truck bounced, the thing shfted into 2nd so fast and was bouncing off of revlimiter.

He didnt break anything but, what a horrible thing to do to a vehicle, esp with that many mile on it, nothing is even close to being broken in yet, but oh well it was fun.

take care man, I hope you get her fixed ok.. Maybe a 3/4 ton t-case. I remember the old Blazers withthe 4hi, 4lo, 2 hi and 2lo tranfer cases, boy did those things scoot in 2 low, talk about short gears, wow.

pauly

will a HD t-case bolt up?

I knew i should have went 4L80e

[Pauly]

Apparently the HD tcase will bolt up and has a 2000 lb ft rating.

here is Parish's site, follow his lead for a bullet proof drivetrain.

he is running 10's now with 1000 rwtq
http://www.neufamily.org/03html/driveline.html

pauly

[treyZ28]

Apparently the HD tcase will bolt up and has a 2000 lb ft rating.

here is Parish's site, follow his lead for a bullet proof drivetrain.

he is running 10's now with 1000 rwtq
http://www.neufamily.org/03html/driveline.html

pauly

I cant view that site at work. Can I use a 2500 t-case or does it have to be 2500HD. are they different? is the 2500 better than 1500?

I got a 2500 t-case lined up for $500 with 4k miles on her.

also, can the t-case come out without the whole trans? that trans pulling thing sucked.

[Butch 02 Denali]

Drop an NVG149 AWD case in from a Denali, Escalade or SS. It will bolt right in to any 4L60 or 4L65 and has a 2300 ft lb rating!!!!

This is the t-case that Parish wanted to use but it wouldn't bolt into the 4L80. This leads me to believe that the 2500 T-case from a 4L80 won't bolt into the 4L60 but I'm not positive about that!

[treyZ28]

Id love to but from what I hear the AWD system will bolt up but i am missing many of the electronics and PCM stuff

[Butch 02 Denali]

There is no electronics or tuning required for the NVG149. It is a standalone mechanical transfer case that uses a vicous clutch to transfer anywhere from 0-100% of engine torque to either the front or back. No switches, nothing, bolt it in!

I see on another forum there is a guy attempting to machine up an adapter to use this awesome transfer case on the 4L80's. If he can make that work, that will be THE system for the really fast trucks!!!! I see 9 seconds around the corner!!!

[treyZ28]

If this is the case, i'm seriously interested. more investigation is coming.

will my pcm have a hissy fit?

[Butch 02 Denali]

For the T-case, no, the PCM won't even know it's there. For the 4L80, definatly!! You will need a custom tune. Brian should be able to do this. If not Wester's can, he's already done some of these.