Vibration gremlin

[shanebo]

Ive posted in the drive train thread about my vibration, Ive posted in the transmission thread about my vibration...now this vibration has officialy become a "gremlin" as it seems to have no particular cause...Does it when it wants to and then quits. It just comes and goes...some times when im taking off from a stop...other times when im driving over 75....and yet other times it seems to be RPM oriented, then it dissapears all together and does fine and runs like a top. It stopped shuttering when taking of from a stop but now its seeming to vibrate at around 3000 rpms, then it stopped all together about half way home and hasnt done anything since...This Eagle has definatly has a mischievious streak in her.

[Hawk258]

Ok, I am not the most mechanically inclined, But this might seem like a stupid suggestion, but have you checked your wheel bearings or maybe some debre/water in your wheels, other question, I haven't read your drive train post, but "If" it is Manual you might also check the pilot bearing in the transmission as well, These are just best "guesses" as I don't have hands on with the vehicle. other suggestion is a long shot but maybe a CVC? You might try getting it up off the ground and testing it, I just don't know a good way to suggest doing that. I would also check for irregularities in the tires, You may have tread separation in progress, these are just off the cuff please take it for what it's worth, (about .2 cents before adding in current inflation))

update: Pinion bearing in the diffs, double check you universals, Splines in the drive line, maybe even check your drive line weights, the wheel weights and drive line weights, I am just throwing out suggestions, sorry if this is already covered.

[shanebo]

 Thanks Hawk! didnt even think about the pinon bearings in the rear diff. Im really hoping its nothing in the rear end but its really starting to point at that....I hate working on rear ends. I think putting it up on jack stands and running it is my next mode of action.

[AMCKen]

My SX4 has an intermittent vibration when around 110kph (68mph) (c.2700rpm) or more. It comes and goes in about 90 second intervals at constant speed/rpm. I'm beginning to think it might either a wheel imbalance that get in-sync / out-of-sync. Or maybe even the belts on the engine. The alternator belt is a tad loose so I'm going to fix that and see if things change.

[shanebo]

I just got back from a ride in the the Eagle. I wrapped up the engine pretty good going through all the gears. It does seem to vibrate at around....3000 RPM's cant say for sure as the Tach gets stuck at 2000  That would make some sense as the car is probably running at around 3000+ RPM's at 70-75 MPH with a 4 speed. Im wondering if maybe the harmonic balancer could be bad. It still doesnt explain the occational shutter when taking off from a stop but at 32 years old theres a good chance there is more than 1 "Gremlins" at work here. Im gonna change out the front and rear diff fluid here in the next few week which will give me a chance to see whats going on inside there. This is sure frustrating....Ive always wanted a gremlin but not inside my eagle 

[Hawk258]

LMAO, Good point, I just hope you don't have too much play in the yoke of the pinion. You might take a peek in your distributor too for play, It "Might" cause some shutter at take off, Not sure about the higher RPMs but it's one other area that generally gets over looked in trouble shooting. it could make a world of difference in performance in my mind. Again this is just running some ideas that "Might" give a few less places for those gremlin's to hide. This is like finding one key on a keyring of a hundred in the dark with no flashlight.

[shanebo]

It sure feels like that Hawk! The Ambassador side of me wants to throw in the towel and let my mechanic find the problem for the low low price of an arm and a leg....However the Rambler part of me is telling me not to give the mechanic a dime and to fix it myself.

[GRONK]

The stock distributors are known to crossfire at 2800+ rpm.  That is the biggest advantage of the TFI upgrade.

I also recommend having the wheels ballanced. 

on another note, I have the trailer in my possesion now so we can get serious........   

[shanebo]

Hows your schedule next week lookin Gronk? Ill get out there and air up the tires and get the blue one started so we can drive it up on the trailer...Maybe we can take the old SX4 for a quick spin too and see what you think about it. Ill give ya a call this week and maybe we can get stuff lined up.

[GRONK]

What works for you?  Weekend is best for me but I can be flexible durring the week with a heads up.  I'd be glad to help out w/ the gremlin.

[Hawk258]

Do I have to state the obligatory "Don't forget the barley pop"? J/K Good luck you 2 I would like to know what the verdict is.

[mechanic80]

Being a master of the obvious: Engine/trans mounts?

[shanebo]

When Gronk comes up to pick up the other 2 cars maybe he'll have some suggestions after driving it. I know I get very OCD with my cars...what would be a small squeak to everyone else sounds like the engine falling through the bottom to me...Maybe between the 2 of us we can diagnose somthing.

[shanebo]

Ok so I have linked the vibration to RPM's. It does it when the car is in neutral and reved as well as being driven. 3000 + RPM's seems to be when it does it.....Im definatly thinking harmonic balancer at this point....Do you guys think Im on the right track with that?

[carnuck]

Or a messed up flywheel/flexplate? If auto and it has a lockup converter, they wobble when going bad and clutches have been known to come apart and cause vines too.