Strange noise from drivetrain

Brianj5600

Brianj5600

TJ Expert
Joined
Jul 4, 2018
Messages
3,350
Location
Middle Tennessee
I'm getting an odd noise when slowly getting on or off the throttle. It seems to only make noise when driving and there is no load. The noise seems to be coming from the trans, 42rle, or t-case. I can't really describe the noise other than a growl? Is there an easy way to inspect a t-case chain?
 
Today when I was exiting the interstate, I put it in neutral and sounded like rocks in a tumbler. I put it back in gear and the noise went away. What should I be looking at?
 
Are you sure it's from the driveline? I would check that the exhausts isn't touching anything.
 
Brian , it may be a u joint that’s ok under load , which is rare, but pull the front shaft and see what happens..I’d lean toward the double cardan front joint . That will take the transfer case out of play also.
 
The exhaust was close, but not touching. I moved it over and have a little over 1/2" now.

If the noise is there tomorrow I will pull the front driveshaft.

I may have a couple things going on. Last time I went wheelin it seems like a couple of times on fairly easy obstacles it felt like something in the driveline slipped a few teeth. I have re-geared since then and both R&Ps looked great. I know there are many variables, but what is the life expectancy of a 241 drive chain?
 
It could be pinion noise on coast. I hope not.

The TC chains are tough , but they are known to make noises if stretched .
 
Put it in and out of 4wd low, high, etc. a few times and see if it gets better. Mine did something like that leaving the dunes a while back. Seems like something in the transfer case didn't quite go back into 2wd. Sound almost like someone put a zip tie on my driveshaft and I could feel it in the transmission shifter (NV3550)
 
Brianj5600 said:
@AndyG wins the prize! I pulled the front driveshaft and the noise is gone along with some vibration! Thanks for the suggestion.
Click to expand...
Many shops pull the front shaft first when chasing a vibe .

The shaft itself can be damaged or out of balance , or the joints or the double cardan can be the issue.

There’s can be way more to it , but that’s at least a start.
 
Update, I tried rocking the Jeep back and forth and checking for slop in all the u joints before I pulled the front driveshaft. I could not feel any problems. I played around with pinion angle in the rear and that helped some too, but there was still some vibration.

I finally got around to inspecting the front DS u joint at the axle and there was a few needles that were half as long as they should be. I put a new u joint in and everything is smooth and quiet. The noise when coasting is gone too.
 
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