thunder550

iTrader: (70)

That's what I was thinking....since you can normally put the trans in park and the truck will still roll if the transfer case is in N. Having the x-fer case in N completely disconnects the transmission from the drive train. Do the tranny and the x-fer case share the same fluid? If it really is the tranny then I am worried that a piece from the trans worked it's way into the x-fer case and locked it up as well. That would really suck. Either way, something is screwed in the t-case I think.

vanilla, temps were low. I had my truck sitting at mom's house for about 3 hours prior to the 2 mile drive to my dad's. I had hit 45 tops on the way over, and didn't have more than about 10-15% throttle when I was hearing the clunks. I gave it probably 25% when I started hearing the grinding noise, and was only moving about 15 mph or so. I didn't feel anything slipping. I don't remember what was replaced before, I think clutch packs, bands, servos, valve body, maybe some kind of hardened internals but I'm not sure. I'll have to call my tranny shop on Monday and see what they did.

1slow01Z71

iTrader: (36)

tcase and the trans are totally seperate. The tcase uses GM autotrac blue fluid and as you know the trans uses atf. If the trans goes you dont have to worry abotu it getting into the tcase.

thunder550

iTrader: (70)

That is great news. Is there a way to test the tcase once I pull it out without opening it up?

gonzo 6.2

iTrader: (8)

Does your built 4L60e have a billet servo?

KySilverado

iTrader: (7)

I doubt that your T-Case will have any issues. They are near bulletproof from what I have read. As mentioned I also bet that the output side of your trans is locked. I'd venture to guess the output sprags. This has your driveline locked up.

thunder550

iTrader: (70)

Will a locked up output shaft keep the t-case from shifting into N? Once the t-case is in N the transmission is out of the equation. When you put the tranny in P it locks up the output side of the trans, but with the t-case in N the truck will still roll. Or is there something I am missing?

thunder550

iTrader: (70)

I dunno if they were billet or vette, to be honest I don't know a lot about trannies at all, other than the very basics.

DrX

iTrader: (7)

Depends which t-case you have but here are some excerpts from the GM manual for your model/year. If you get the t-case into N, then the output shaft of the tranny is "disconnected" from it.

NVG 261-NP2:

"This transfer case also has a neutral position. A shift to the neutral position allows the vehicle to be towed without rotating the transmission output shaft. In the neutral position, the rear propeller shaft will rotate the transfer case rear output shaft, in turn rotating the oil pump, providing constant lubrication during towing. Note, this neutral position is a 4WD neutral, meaning the front and rear outputs of the transfer case are engaged as though in 4HI. With a disconnecting front axle, there is no power flow to the front wheels, allowing towing with the front wheels off the ground or flat towing without driveline binding. Again, the transfer case should not be shifted into or out of neutral unless the following criteria have been met:

• The automatic transmission is in neutral or the clutch pedal is depressed.
• The vehicle speed is less than 3 mph (5 km/h). "

NVG 236/246-NP8:

"This transfer case also has a Neutral position. A shift to the Neutral position allows the vehicle to be towed without the rear axle rotating the transfer case main shaft and the transmission output shaft. Neutral position may be obtained only if the following criteria has been met:

• The key is ON.
• The automatic transmission is in Neutral, clutch depressed on manual transmissions.
• The vehicle speed is below 5 km/h (3 mph).
• The transfer case is in 2HI mode.

Once these conditions have been met, press and hold both the 2HI and 4LO buttons for 10 seconds. When the system completes the shift to neutral, the red neutral lamp will illuminate."

NVG 263-NP1:

"This transfer case also has a Neutral position. A shift to the Neutral position allows the vehicle to be towed without the rear axle rotating the transmission output shaft. Neutral position may be obtained only if the following criteria has been met:

• The engine is running.
• The automatic transmission is in Neutral (clutch depressed on manual transmissions).
• The vehicle speed is below 3 MPH.
• The transfer case is in 2HI mode.

Once these conditions have been met, press and hold both the 2HI and 4LO buttons for 10 seconds. When the system completes the shift to neutral, the red neutral lamp will illuminate."

thunder550

iTrader: (70)

Mine is a 246. Sounds to me like it's the t-case, not the tranny. Thanks for the post!

KySilverado

iTrader: (7)

Really didn't think about the different transfer cases. I am familiar with the NP8-Autotrac. As DRX posted. To get a neutral in it you must have the key on. Transmission must be in neutral. If there is as much damage in your trans as it sounds I doubt you will get it in neutral electrically, maybe manually and then couldn't get the transfer case to neutral. All speculation. I just know the transfer cases are strong and still doubt you have hurt it.