Archived Grinding noise from front drive

[steamer]

I have a '95 2500 w/5speed and 95,000 miles. Today, with 10F out, 24 inches of snow predicted for tomorrow, I have to develop a problem with my 4x4 engagement. A grinding noise just showed up. It happens when accelerating from a stop, and as I go thru the gears, it grinds for a short period of time in each gear. And some times it would occur when driving along at highway speeds.



There also is a slight "clunk" noise that appears to come from the transmission or the transfer case. I had my buddy get out and try to see/hear where the noises where coming from while walking along side the truck. He couldn't't tell. But he did notice that the drive-shaft between the transfer case and the front diff would be turning, but not all of the time.



As I thought this could be some type of intermittent 4x4 engagement, and at speed, I thought it best to put it into 4x4 for the rest of the drive home.



Is this from the cold? Is it the vacuum actuator? Help I will NEED 4x4 tomorrow!!!!

 

[moparguy]

I would check the vaccume hose that terminates on top of the front axel. Then trace it back to the fire wall looking for problems. Sounds like the little vaccume motor isn't totally engaging the coupler in the front end that actually causes it to engage four wheel drive.

 

[Joe G.]

I think there is something wrong inside the transfer case because of the symptom of the front drive shaft not turning at a steady rate when the T-case is engaged. If it was a vacuum problem then the drive shaft should always turn, but the front axle would not be connected by the vacuum shifter.

 

[jlhartak]

Sounds like partial ingagement of the vacuum axle disconnect or the tranfer case. Raise the front axle off the ground, then with the truck shut off shift the transfer case into four wheel drive, you should not be able to turn the front drive shaft by hand. Get your Buddy to shift it in and out a couple of times as you try to turn the drive shaft. If this works OK then it is a problem with the vacuum disconnect on the front axle. Check all the vacuum lines running to the axle for cracks leaks, etc. it may be the colder weather has frozen some accumulated moisture in the line resulting in intermittent ingagement of the axle disconnect. Hope this helps.