knocking noise

toyotatech · December 18, 2005

2003 1500 hd 6.0 auto 50k

When I put it in auto 4wd and I am going up a hill (slight load) I hear a knocking noise coming from the front. If I put it in 4wd high the noise goes away. When the truck was new I had a problem with service 4wd message. They replaced the encoder motor. I remember reading a tsb after my work was done where gm wanted the tech to check something in the front diff or axle for damage. Any suggestions where I might look first?

GM-Tech · December 18, 2005

Yes there could be damage to the sleeve that engages the axle. Do you know if they checked that?

Was it really necessary to post this identical question three separate times in the same area?

toyotatech · December 19, 2005

Yes there could be damage to the sleeve that engages the axle. Do you know if they checked that?

Was it really necessary to post this identical question three separate times in the same area?

<{POST_SNAPBACK}>

They are not identical questions. I only get the knocking noise when in auto 4wd. Isn't this sleeve that engages the axle also in use in regular 4wd high. I don't get any noise in 4wd high. I have no idea if they checked the sleeve when they replaced the encoder motor. How do I go about checking the sleeve? Easy or major surgery? If the sleeve is bad, What am I looking at replacing?

GM-Tech · December 19, 2005

My apologies. I didn't make a word for word comparison of the three posts. They just appeared the same.

In any case, here's the procedure. It's really not that big a job. You're just looking for damage to the sleeve...

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Disconnect the wiring from the front axle actuator motor and the axle housing.

Remove the right stabilizer shaft link assembly.

Remove the six (6) right front wheel axle shaft companion flange bolts. Reposition the right front axle shaft away from the companion flange.

Remove the five (5) inner axle shaft housing bolts from the differential carrier case.

Remove the two (2) axle shaft housing nuts from the bracket.

Important: When the right front axle tube is removed from the vehicle, several components may fall out. Position a receptacle such as the engine oil drain with screen under the front differential carrier to catch these components.

Position an oil drain pan under the front axle, as about ½ cup of differential fluid may drain from the differential as the right front axle tube and shaft assembly is removed from the vehicle.

Remove the right front axle tube and shaft assembly from the vehicle.

Inspect the engagement sleeve for damage to the internal teeth. If damage is found, replace the sleeve. This sleeve is powdered metal and will fracture if dropped.

Clean the end of the axle/tube assembly and the differential carrier flange of the original sealer.

Clean any metal shavings out of the axle housing if there are any, including flushing the fluid if needed.

Position the axle/tube assembly with the companion flange resting on the bench.

Important: The bevel on the outer circumference of the engagement sleeve must be positioned into the axle shaft tube assembly.

Reassemble the right front drive axle components ensuring that the spring is properly positioned over the end of the fork assembly , and that they are positioned to the engagement sleeve and the pilot in the axle shaft tube.

Apply sealant, GM P/N 1052942 (Canadian P/N 10953466), or equivalent, to the axle housing to differential carrier sealing surface.

Position the axle/tube assembly to the differential carrier and the mounting bolts.

Tighten

• Tighten the axle/shaft assembly to frame bolts to 100 N·m (75 lb ft).

• Tighten the axle/shaft assembly to differential carrier bolts to 40 N·m (30 lb ft.).

Reposition the right front axle shaft to the companion flange and install the (6) bolts.

Tighten

Tighten the bolts to 79 N·m (58 lb ft).

Install the right stabilizer shaft link assembly.

Tighten

Tighten the stabilizer shaft nut to 10 N·m (89 lb in).

Route and reconnect the wiring harness.

Verify the fluid level in the front differential. If fluid is required, fill with SAE 80W-90 Axle Lubricant, GM P/N 1052271 (Canadian P/N 10950849), or equivalent.

Reinstall the skid plates (if previously removed).