Do rear driveline vibes cause lots of noise?

[DerMeister]

I've got some minor vibes when accelerating, nothing that has made me want to drop the T-case. I'm talking a 2" lift on 30's with a 2000.

Been driving on the highway a lot more lately and realize I have a problem. At 70mph plus I have some really loud noises coming from what sounds like the rear, and some minor vibes. The noise exists while on the throttle, especially when increasing in speed or going uphill. While coasting at those speeds the vibrations lessen, and the noise goes away.The only way I can describe the sound is to say that it sounds like a muffled jack-hammer.

Gotta be rear drive-line vibes right? Would like to get this fixed before I break something. Thanks!

 

[G2WANIT]

Do you have a SYE? Stock gear ratio or 4.10?

 

[AaronNW]

Just go under and give the drive-line a wiggle and see if its loose. Grab it and move in all directions, any noticeable slack is bad.

 

[sidriptide]

look for lose U joints or and dry red rust dust build up around them, also check your t/case output and rear axle pinion for any wiggle at all.....
something is wearing out back there, catch it now.

 

[old_man]

Check your motor and transmission mount to see if they are allowing enough flex for your exhaust to hit the cross member or the body anywhere else.

Other than that, check the centering balls in the dual cardan joints.

 

[DerMeister]

Thanks for the posts, lots to look at. Should the slip yoke have a little bit of movement on the output shaft?

 

[kastein]

Can you record the noise?

I've got way too much experience with rear driveline vibration noises. My 98 had horrible vibe issues even at stock height and with saggy rear springs, they're almost gone now that I put new (stock HD) leafs and an SYE in.

 

[DerMeister]

I have some news to report, I think it may be the transfer case. Got the rear tires off the ground and secured the axle with jackstands then had my girlfriend run it up to speed. Definitely sounds like everything is coming from within the transfer case, sounds like the chain is scraping badly.

I'm thinking about taking it to a shop so they can look at it and let me know.

Everything with the drive shaft seems tight. Would I have been able to see it wobbling if it were causing the vibrations?

 

[DerMeister]

Can you record the noise?

I've got way too much experience with rear driveline vibration noises. My 98 had horrible vibe issues even at stock height and with saggy rear springs, they're almost gone now that I put new (stock HD) leafs and an SYE in.

I should've recorded the noise when my dad and I had it up. I might put the rear end on jackstands again and get it running just to record it for you guys. Some vibes, and a lot of noise coming from the T-case. I can't imagine it being normal. I also noticed the output shaft and/or slip yoke has a fair amount of play. It wasn't like that a few months ago.

Anyways I got a used T-case today for $150. It's from a 99' with 155k on it. Looks to be in good shape, but I'll check the fluid, chain, and shift it through the gears before I put it in. I also got a complete drive shaft in case mine was out of balance.