Annoying vibration @1500 to 1700 rpm

[john robertson]

All of a sudden my car developed an annoying vibration @1500 to 1700 rpm, approximately. It does it in neutral, park, and also while I'm going through that rpm range while driving. When observing the engine, I see no noticeable vibrating which leads me to believe it's in the transmission. I aim to disconnect the converter later today, and I expect the vibration to stop. If that's the case, would it be more likely the problem is in the converter or the transmission? I've checked for loose stuff and haven't found anything. By the way I have HR mounts on the engine and transmission, but never suffered any vibration upon installing them. This is out of the blue. TIA

[Scoobum]

John...unbolt the convertor. If it's vibrating that bad it'll do damage to the trans and convertor. You'd have to have the convertor cut open if that's where the issue is.

[john robertson]

So, I'm assuming that if the vibration is caused by the converter or the transmission, which I will know for sure, soon, there's no recourse to be sure it's the converter, and not the trans, but to install another converter? I can replace it with a stock D-5 to be sure. I was just wishfully thinking there might be some other course of action. 

[john robertson]

So it turns out that the vibration is not in the TC or the transmission but somewhere in front of it. I can't find anything conclusive. I'll just have to live with it unless it gets worse.

[earlbrown]

Pop the serpentine belt off and run the test again.

[Scoobum]

Earl's prolly nailed it.

[john robertson]

Hey, thanks guys for your suggestions, but just to finish up for future searches about unexplained vibrations, I failed to mention that the last thing I did before I noticed this objectionable vibration was I tightened my body mount bolts. Apparently, this is what caused it. I tried to reverse myself and loosen them back up, but nothing changed. The mounts were original and as it turned out, were shot. I replaced them over the last couple days with the Energy Suspension kit, and in doing so, the vibrations I caused by tightening up on the originals are gone. Nothin' but smooth sailin' now.   

[earlbrown]

You shouldn't be able to ''tighten up'' the body mounts.   They have a sleeve that your tighten against and have rubber on both side to do the job of isolating/dampening.

[Scoobum]

Do yourself a favour...and torque them to 52 foot pounds...facto ry spec. Torque specs are there...for a reason.

[Steve Wood]

After awhile, the rubber is gone and you are left with steel which transmits all vibration from the frame to the body