Engine Vibration

I'm sorry, I obviously need to clarify.I meant a screwdriver that's three or four feet long w/ a plastic handle.After 14 years of being a professional mechanic, (10 at a dealership, 4 on military vehicles) I can assure you this is standard practise for finding noises & vibrations. Yes, a stethescope is the proper tool but, I personally prefer to use a very long screwdriver for multiple reasons: 1) I believe it's safer because most stethescopes have a metal end that is only a foot to maybe a foot & ahalf long attached to a rubber hose. Wich means you have to extend it w/ your arm to reach into the engine compartment.W/ along screwdriver you can hold the handle right below your ear 2) With a stethescope you have two ear pieces in your ears wich may pull your head down or get caught on eye glasses, safety goggles,etc. A screwdriver you can let go or be pulled away from you. It's not attached. 3) THe lenght of it allows you to have your head &ears out side the engine bay or out from under the chassis if on a lift. for better diag. 4) If you've ever bought a high dollar stethescope off the "tool" truck for x amount of dollars per week to burn a hole in the tubing or melting an important plastic component on a hot exhaust manifold... it can be quite frustrating. I apologize, & will atempt to be more specific in the future.

Thank you everybody. I may need to clarify again a bit. It is not a noise or misfire type shake. It is a physical vibration. Droning type vibration that shakes engine compartment and interior. It is only in gear at idle. It is less noticable if in gear idle is turned up, and practically gone in neutral or park. It is not while moving or driving. Only standing still. Vibration has always been present since we purchased the car. It has been masked in the past by other things, and less noticable, but everything externally attached to engine has been replaced, rebuilt or checked. Engine mounts have both been replaced, and the transmission mount was replaced when the transmission was reinstalled after rebuild. I have a stethescope, and I have used it over and over again on this vibration. The vibration is most detected with the stethescope at the bottom of the engine block from front to back and from the oil pan from front to back. I have set the parking brake, put the car in gear, and crawled under the front. I can grab the frame rails, the cross members, the exhaust system, the suspension and the steering linkage and I cannot feel the vibration. I put both my hands on both sides of the oil pan, and the oil pan vibrates/shakes both my arms. I have run the engine with the belt off, so I know it is nothing in the alternator, water pump or fan. It does not matter if engine is cold or hot. Vibration is the same. I appreciate all the help and suggestions. Keep them coming. Thanks.

any C4 experts?
something when the auto engages the engine? I know manuals a lill more (still not much) and might check a throw out berring, pilot bushing kinda thing to that.
fluid not gettin to the tq converter?

"...only in gear at idle..."
U said it drives/shifts OK brother?

"...practically gone in neutral or park..."
may B cuz the engine revs change. = rotating assembly (Can U actually feel something knocking as U felt around?) crank hits pan? that'd be weird - main berrings?

IDK...

Yeah, I'd bet money it's in the transmission based on that. Something that should be slipping at idle that isn't - perhaps in the torque converter. I'd put it in D, and slowly bring the revs up and see what it does - especially as you get around stall speed.

chessterd5":3caotdf2 said:

I believe it's safer

Click to expand...

Last word

I disagree in the strongest terms.

That's all I'mm going to say on this subject.

Maybe there's a problem with how the flexplate is attached to the torque converter.

My engine vibrates quite a bit a low rpm in gear with the foot on the brake. 8)
Maybe you have a lumpy cam.

"...Transmission was removed and overhauled (due to knocking noise at front pump/torque converter area). Transmission was reinstalled with rebuilt/new torque converter, new flexplate and new mount....new timing chain with gears, new damper/balancer, new water pump and..."
may B in some of these components? Too many "all @ once changes" 2 B able to isolate something that's THE problem. GO Back to the Transmission company and ask "What's up here?"...

"...I would like some suggestions before I remove the engine. Once I do that, I'm in for an overhaul. I'm in too deep now to guess anymore..."
You're on the verge of a "diagnosis by committee" not always a great system. Some 1 there who can have a look might B the trick? If it's coming out the answ may B evident...

I'd have a look to the transmission 1st, but this suggestion duz NOT come from a mechanic or expert....
;- )

Did you ever solve the mystery of the vibration?
Marc in SF

"...The vibration is only present in gear at idle...."
still thinkin transmission...
or trany/motor interface -