dhpro

iTrader: (3)

My T-case is dropping to neutral a few times the past few days. I put the truck in neutral, punch the 2wd or 4wd button and it shifts back. Truck always drives fine, but the "neutral" lite flashes when this happens. Anyone else had this prob? The t-case is sweating - cud it simply be down on fluid. TRANNYMAN suggested it cud be the motor between that and the tranny as it often goes bad.

trever1t

iTrader: (14)

Or the switches themselves. I have had it happen twice, but not in a while.

dhpro

iTrader: (3)

Never thot of that! Cud be as it always stays in gear...I made an app't at the dealer and hoping it'll get covered under warranty...R/

BigTex

iTrader: (16)

My 03 Z71 Tahoe does that sometimes. 130K miles and climbing. I'm leaning towards the issue being a sensor on the transfer case.

Mine will occasionally display 4HI or Neutral, but will drive fine. Last year, it actually said 4LO, but obviously wasn't. However, when it said 4LO, it had really hard shifts and shift points were higher. When I notice the issues, I just slip it into neutral, hit the 2HI button, the light changes and it stays corrected for a while.

dhpro

iTrader: (3)

Does it throw a code?

BigTex

iTrader: (16)

I get the "SERVICE 4WD" notice on the cluster, but that goes away after I tell the switch to go back to 2HI and restart the vehicle. I believe I did get a MIL light when it thought it was in 4LO. I scanned the codes, but don't recall exactly what the error number was.

dhpro

iTrader: (3)

Thnx...I get no msgs, but I haven't got a scanner to read codes. I'll post when I know more. R/

Grumpy5.3

iTrader: (14)

you need an encoder motor sensor. you can take the encoder motor apart and replace the sensor. You might have oil in your motor causing the sensor to short out. IF you do, the t-case has to come out and apart to replace the bearing/seal that keeps fluid out of encoder motor sensor

dhpro

iTrader: (3)

Great info!!! What happens if I do nothing? It seems pretty intermitant and no effect on drive-ability right now.

DrX

iTrader: (7)

I found this which doesn't sound to promising either:

Transfer Case Jumps Out of Gear


DEFINITION: Loss of the transfer case drive torque during deceleration, acceleration or under load.
Review the Symptoms - Transfer Case and perform the necessary inspections.
High/low shift fork pads

1. Inspect the shift fork pads for wear. Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the fork pads or other damaged components. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Faulty high/low range fork

1. Inspect the high/low range fork for damage or wear. Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the high/low range fork if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Actuator lever worn

1. Inspect for excessive wear on the actuator lever - for not allowing full shift fork travel. Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the faulty actuator lever. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Faulty high speed teeth on range sleeve

1. Inspect for the following conditions:
   • The input gear high speed engagement teeth for wear or damage
   • The engagement teeth on the range sleeve for wear or damage Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
   Replace the range sleeve if the teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the input gear if the engagement teeth are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

High/low planetary carrier

1. Inspect for the following conditions of the high/low planetary carrier:
   • Low speed engagement teeth worn or damaged
   • Cracked carrier housing
   • Pinion gear bushings worn or out of position
   • Pinion gears broken or damaged teeth
   • Pinion gears seized Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the high/low planetary carrier if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Input shaft pilot bearing

1. Inspect the bearing in the input gear and the rear output shaft journal for excessive wear. Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the bearing and the rear output shaft if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Input gear

1. Inspect the input gear for broken or damaged teeth. Refer to Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
2. Replace the input gear if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Document ID# 833621
2004 Chevrolet Avalanche - 4WD