1G Vibration in the driveline that starts around 3k rpms

[blakkat]

I have a vibration somewhere in the driveline that starts around 3k rpms and only goes away when I get into the throttle quite a bit, or put the clutch in and let the rpms drop.

thinking either the rear diff or driveshaft carrier bearing. Any experienced dsmer's know what this could be

 

[jtmcinder]

With regard to the rear diff being caked in crud, I was about to post that sometimes a car can have two separate problems at the same time. Then I remembered that this is DSMTuners (as opposed to one of the other sites that I troll ... er, I mean, visit) and laughed at the idea that there might be only two separate problems.

 

[blakkat]

Yeah I know, I'm a mechanic. There's quite a few problems I need to fix on this car. I may be able to take a video of the sound later tonight, it's kind of hard to describe. It's kind of a metallic grinding that accompanies the vibration almost like a bearing is going out or something.

 

[kddrosos]

I hope this isn't too late to bump this thread, but I'm having a very similar problem, if not the same. Under about 10% of load in any gear, I begin to hear a grinding sound around 3000+ RPM. I can even hold it if I'm steady with thew throttle. If I begin decelerating above said RPM, I hear the grinding for a faint second. If I push throttle past around 10% or just under, car accelerates normally with no sounds, regardless of RPM/gear. I have my balance shaft eliminated. I'm totally convinced it's between rotating engine parts/sensors and the input-shaft of the transmission. I also get some harsh-sounding vibrations from the motor upon engine-braking from 4000+ RPM. Might be irrelevant though, as I was told this was a product of having 272 HKS cams.

 

[blakkat]

Honestly like a week later my tensioner blew out. In the process of gathering parts to redo all the timing components and well see if it's related to that area.

 

[kddrosos]

Well that's fairly alarming. Hope everything's OK with your motor. Does my description sound similar to what you're dealing with though? Like a more-than-subtle grinding sound that I can hear just over my exhaust? Only happens when i press in the gas slightly, but goes away under more load. It's weird, but somewhat nerve-wracking just because it could be something very important. Good luck with your timing install.

 

[blakkat]

Yes it sounds exactly like that. Mine was a little more harsh though