Whats My Noise? 05Chevy 2500HD 4x4

[TruthWalleyes]

What’s my noise?

I have a 2005 Chevy 2500HD 4X4 with a new noise.

When I change from 4 wheel drive to 2 wheel drive I get a very loud clunk as the front wheels disengage. And It takes up to two miles for it to finally disengage. When it finally disengages there is a loud clunk.

I have checked the drain plug (normal fillings) and refilled the front differential with new synthetic oil. Also checked the electric solenoid and it does thrust the plunger in and out at what appears to be a normal rate of speed.

[Macgyver55]

Its not all that abnormal to hear some amount of noise when disengaging, but a couple things may affect it in a negative way.

First, check tire pressures to be sure they are correct as any speed imbalance between front and rear will exacerbate the problem. Also, make sure when you disengage the 4wd that you are neither accelerating or decelerating if you can so there is no torque on components.

When you use the 4wd is it long enough to warm things up or is it just for a short time to get out of a bad spot? Increased drag caused by very cold gear lube can be part of the issue. Running it in 4wd for a few minutes will help warm the fluid and decrease drag on the gears, just dont do it on dry pavement.

[TruthWalleyes]

Thanks for the response. This is my dad's vehicle, and talking with him, he had blown a tire pulling someone out of a plowed field last week. He put the spare tire on (This would be a possible different tire pressure, and amount of tred). This is happening during a constant speed, and is a rather large clunk...But, if it is taking upwards of 2miles to disengage, it's likely that he may be accelerating or decelerating during this time. He's going to put two new tires on this week to see if it resolves the problem.

Thanks,