HAZE

anyone have a manual with an exploded view of a np 246 transfer case ? i've been looking for one but found out i have to order it. i kinda need it now. so any help or links are appreciated. e p.s the reason i need it is my truck won't shift into 4wd all the way, suspect the auto trac thing in there is to blame.

HAZE

ok, sorry it's a nvg 246, it says right on the tag new process gear. but i guess that's the old name, nvg's site says np8=nvg246 anyway anyone got a picture that shows the clutch packs ? someone sent me an axle picture , have to figure out who that was. thanks e

HAZE

so i took it back to the shop today, we did basically the same test as last time, racked it, ran it in 4 hi and 4 lo , can't stop the wheel with your hands and it transfers power to the other wheel like it's supposed to, but under real trque loads it won't transfer enough power to turn the wheels. apparently it has a viscous coupler that transfers power gradually when in auto 4wd so it's either a bad sensor or the coupler is shot. everyone i talked to said they've never seen one fail in these trucks, so hopefully it's a sensor malfunction and not the computer or the coupler. hard to believe i could blow it in the sand when alot of guys are doing 4 wheel launches at the strip. e anyway, could still use the photo.

BigTex

iTrader: (16)

Are youhaving problems with the front wheels? Have you checked the front differential? The autotrac system uses a solenoid to engage the front wheels. The transfer case is put into 4wd and autotrac uses the front solenoid to engage or disengage the front wheels.

Here you go:



In the 4HI mode, the power flow to the rear propshaft (10) is the same as it is in the 2HI mode. To deliver power flow to the front propshaft (13) during the 4HI position, the transfer control module commands the encoder motor (15) to apply the clutch to a calibrated torque. The encoder motor (15) turns the control actuator lever shaft (14). A brake in the encoder motor (15) holds the control actuator lever shaft (14) in the full clutch position. The control actuator lever shaft (14) is cam designed and the cam action moves the clutch lever (4). The clutch lever (4) pivots on the clutch lever pivot studs and moves toward the clutch apply plate, to engage the clutch. As more pressure is applied to the clutch apply plate, the clutch discs are compressed. Using inner clutch discs, which are engaged with the clutch hub (5), and the outer clutch discs, which are engaged with the clutch housing (6), the power flow is delivered to the clutch housing (6). The clutch hub (5) is splined to the rear output shaft (9), and the clutch housing (6) rotates on a needle bearing on the rear output shaft (9). The chain drive sprocket (7) is splined to the clutch housing (6). The power flows from the drive sprocket (7), through the chain (11), to the chain driven sprocket. The driven sprocket is splined to the front output shaft (12). The power flow is delivered to the front propshaft (13) through the front output shaft (12).

During the Auto 4WD mode, the power flow is the same as it is in the 4HI mode. Except, during the Auto 4WD mode, the encoder motor (15) rotates the control actuator shaft lever (14) to the correct torque level positions. Rotating the control actuator (14) to the various positions changes the clutch torque level. When a difference of front propshaft (13) to rear propshaft (10) speed is recognized, the transfer case control modules command for more, or less clutch torque.

HAZE

thanks big tex, that's just what i needed. i'm not sure what you are getting at with the front axle ? the front axle is engaged with an actuator and is either on or off, it does'nt have anything else to do with the auto trac. from the tutorial there it looks like i either have a bad encoder motor or corresponding sensor or i blew the clutch pack. if the encoder motor is forcing the clutch lever to the full position, then it's more than likely the clutch. if it is not fully engaging the lever than it's either the encoder motor or sensor or just a plain mechanical part failure. i can't thank you enough for the picture and info, this will really help me troubleshoot this p.o.s. e

LS1NOVA

iTrader: (12)

I have seen many of these with burnt up clutch packs under warranty. Pretty easy fix if its just the clutch packs. You can remove the rear half of the case and its basically right there in your face. There is also a shim that determines the preload on the clutches but usually the stock shim ends up being right. good luck

HAZE

nova, is there a fix ? any reason why i would blow a clutch pack spinning tires the sand ? if that's the case why aren't guys burning them at the strip ? i'd like to make it so the clutch is always locked when in 4x [no autotrac] any ideas ? never would have got this pos transfer case if i know it was so wimpy, hd my a$$. e

LS1NOVA

iTrader: (12)

Not sure on how to keep it from happenening again. I only have experience with rebuilding them at work. Will look into it as I am interested myself.

HAZE

nova, the sensor on the side of my encoder motor got a groove worn it it when i shredded my output shaft boot. the dealer says i can only buy the whole assembly for $ 550, any idea where i can get the black shaft position sensor by itself [six prong plug]? i don't know for a fact that it's the only problem but it is the only part that appears to have any damage. thinking the sensor is reporting that it is in full locked position when it fact it's not. let me know if you can help. if not it's off to the junkyards i go. e p.s if you figure anything out on bypassing the auto trac let me know, i never use that anyway.

LS1NOVA

iTrader: (12)

I can check at work on the price, since I can buy for 10% over cost. I have a used one but it is 3 hrs away at my storage building. I would sell it for $100 shipped.