Engine/Transmission (1998.5 - 2002) Transfer case noise

[bwbody]

Transfer case's making rhythmic thumping noise in 4wd. 518 trans. Occurs ~ every 2 sec @ 25 mph. Worse under load, almost gone when coasting/no-load. 4wd does engage.



Not too sure about the NV241D t-case, but I assume it's chain drive.



Broken tooth? Bad drive chain or link?

 

[JAlford]

Is it making the same thump in low and high range? Could be the CV off of the front drive if it stops when in 2wd. Have you checked the axle, are you sure it is transfer case? Sounds much like a broken ring tooth on the front axle, at that frequency.



Jeff

 

[bwbody]

Jeff,



I thought about the CV joints, but thought that they would cause an occurrance at a higher rate because of the RPM. You'd expect it once w/ every revolution of the front tire, or so, right? This is happening at a much slower rate. I'll have to check out Low Range this AM & advise. My recollection is that it is happening in Low Range, as well.



For what it's worth, I do feel it in the transfer case lever. Don't know if the vibe/"thunk" would localize that far if it was coming from the front pumpkin. I'll let you know.



Thanks for the ideas.