getting a rythm type sound in the tranny t-case area??

[85mudblazin]

I have noticed that since I have pulled up my carpet I can hear a rythm type sound, it sounds like something spinning kind of how a train starts of, then it goes faster and faster as I speed up but never gets louder.
I think it is coming from in the tranny area or maybe it is traveling and coming out of the t-case, anyone else hear this same type of noise??
Thanks alot
-Chris

 

[poinzey]

I have the same problem with my transfer case. Usually I don't hear it until I've been on the highway for an hour or so. Not sure exactly what it is, but in my case I believe it has something to do with the range forks in my tc. My tc needs an overhaul, and I think the range fork(s?) is toast as I can only shift it if i have both axles off the ground at the same time. Anyone else have any ideas???

 

[mountainexplorer]

I have a '78 Blazer that has a warped flexplate. You can visually see the flexplate vibrating at an idle. When I speed up, it spins faster, and while driving it acts like a pulsating sort of sound/vibration.

I had a '78 3/4 ton 4x4 truck that had a similar sound at higher speeds only. It turned out being a rear driveline out of balance (and the splines in the slip yoke were worn).

I would guess first that something in the rotating parts of the drivetrain is out of balance. You just have to match the speed of the sound to what would be spinning that fast at the time you hear it. (for example, a torque convertor is spinning all the time even in park, where a rear driveline is only when driving).

Sound can also resonate through the drivetrain. I had a pinion bearing go out in a rear end once, and the sound made it seem as if it were something grinding in the tranny itself.

 

[85mudblazin]

yea the sound sounds like it is coming from right in front of my t-case shifter, ill drop the tranny pan and see if I can tell anything in there.