Vibration

[Bobby Clobber]

O.K. Folks, up for a challange?

I'm feeling a vibration through the go [B]and[B]stop pedals . Not harsh but almost like a buzzing feeling that doesn't stay all the time but ( and I know this sounds crazy) almost seems like it's harmonic in nature . I say that because I was beside a huge truck this morning in traffic and as we both pulled away the rumble from his machine was felt in my seat and not unlike the vibration I'm experiencing in the pedals.

No noise that I can hear, no grinding, a little whine from the rear end but that's been there since the 410's went in, not loud, just there.

Car behaves normally, shifts properly, etc, but this is bugging me.

Before we go off to the dealer anyone got any ideas? I don't need everyone in the damn dealers shop taking it for a burn, sorry, road test,but if we have to, in she goes. Problem is the dealer doesn't know Marauder from Shinola, last idiot said he really liked my Buick. ( another story)

I mean this could even be a tire , I don't know. Actually ,replaced the fronts only two months ago, perhaps?

:confused: :confused:

[Go Mifuni]

O.K. Folks, up for a challange?

I'm feeling a vibration through the go [B]and[B]stop pedals . Not harsh but almost like a buzzing feeling that doesn't stay all the time but ( and I know this sounds crazy) almost seems like it's harmonic in nature .
I notice the same "vibration" at > posted speeds. It's almost a pulsing vibration. I wonder if your problem may stem from your drive shaft. Is is spinning much faster now with the 4:10's and I remember some having similar issues until they replaced it with a balanced one.

[TripleTransAm]

Is it dependant on road speed? Or "apparent" road speed, by chance?

Here's something to try: with the car in park, raise the engine RPM very gradually and study if you have the vibrations. Focus on the 1500-1700 range, make sure the engine hangs at your test RPMs long enough to get a good feel.

[Blackened300a]

When I did the 4.10 gear swap, I had a Vibration that would be more pronounced at higher speeds even when I wasn't using the brake. Recently I put cross-drilled and slotted rotors with new Pads. After the install, Vibration gone! Turned out while doing the gear swap, The Rear Rotors were a bit hard to remove and it took a bit of hammering to finally get them off. I must have bent it and caused it to wobble enough to cause a vibration.
Your Rotors may be where your Vibration is.

[Bobby Clobber]

Steve,

I'm not sure where you're going with that , but, nothing noticable when in park at any RPM. This seems to be a rolling thing. It may be my imagination, but it seems a little more pronounced at the one/two shift, the more I try to isolate it.

As far as the rotors, I've had the 410's in for 1 1/2 years, and didn't have any trouble getting them off when I did the swap, so it may be , but it's less likely.:confused: :confused:

[TripleTransAm]

I was looking for the same vibration while revving at certain key RPM. But you seem to have disqualified that theory. How long since your last tranny fluid change? What's your PCM code?

I'm suspecting a munched up torque converter clutch, or dead/dying fluid.

[Bobby Clobber]

PCM is BMDO , but I reflashed with DR's Stage 1 when I did the 410's

Only 40K k's on the car, no fluid change:depress:

[TripleTransAm]

I barely started to notice a change in torque converter application behaviour at around 46000 km, ironically close to the recommended 50000 km change schedule. This is with a stock CRD1 calibration on a bone stock car. A lot of that mileage was also very easy going (not comatose, but just normal driving). So maybe if you drive a little more aggressively with more stop/go or lots of lifting off the throttle and reapplying (unlocking and relocking the TCC), it might mean a bit more wear and tear on the fluid.

However, TCC shudder usually only occurs at application of the TCC or in instances where the TCC is applied in a partial fashion (dumbass engineering, in my opinion). For a stock CRD1 calibration, during a normal suburban drive, half of second gear is spent locked at 50% (or slipping at 50%, depending on whether your glasses tend to be half-full or half-empty), and then it's applied 100% immediately after the 2-3 shift. The shudder might be felt as the 50% slippage is not 'clean' and when the TCC is being applied to 100% in other scenarios. If you're feeling the shudder all the time once your TCC has been applied at 100%, it might be a bit more serious since there should have been enough time for the clutch surfaces to grab and stop slipping altogether.

If I was you, I'd go ahead and get that fluid changed anyway, since it'll be due soon anyway.


Related question: since the TCC stays locked until you completely lift off the gas, it essentially acts like a manual tranny clutch system once it's applied at 100%. If you get the vibration at highway speeds (say, 100 kph, enough to keep it in 4th), see if the intensity of the vibrations changes as you gently modulate the amount of power from the engine... the idea being (as with a manual tranny car) if there is a problem with the clutch capacity to hold, adding power as the motor is forcing against a high gear might cause the friction surfaces to occasionally give... in extreme circumstances of manual tranny clutch wear, you'd get an RPM flare-up but you'd probably not feel any vibrations as the clutch wore because of the spring-loaded nature of the clutch disk(s)... I believe it's not the case in a torque converter's lockup clutch.

[Blackened300a]

I was looking for the same vibration while revving at certain key RPM. But you seem to have disqualified that theory

I have noticed that when in park at 1800-2100 RPMs there is a slight vibration in the engine
Not to hijak the thread but WTF is it???

[TripleTransAm]

Not sure. Might simply be a harmonic of the engine pulses at that particular engine speed, might be some tolerances throughout the engine just happening to 'resonate' at that RPM, might be characteristic of V8s, might be pulses from some accessory like the power steering pump, I'm not sure.

I used to have it at on my 1985 Parisienne at about 1600-1800 (as accurate as my little add-on digital tach could be). Very minimal, just enough to wonder if a cylinder was working a little harder than the other 7, nowhere near enough to bother me. I can't tell if my Trans Ams have it, since the exhaust tends to drown out any extra vibrations if there were any. My Marauder does have a sort of vibration at that RPM you describe (1700-1900?) and it actually is felt through the steering wheel as I'm cruising at that speed. For years I thought it was my wheels or tires out of round, but recently realized it's a function of RPM! (ie. same vibration even in park when holding that RPM).

So now I'm thinking that, because of the weird pulsing of the RPM when tugging the wheel in drive at idle, that maybe my power steering is the culprit. Figures... I've already had to change the alternator and the tensioner a couple of weeks ago, and a buddy did think my power steering pulley had too much slack in it (maybe that's the harmonic wobble at 1700-1900?).

[gohogs]

I have the same vibration in the steering wheel that is definately RPM related at about 2000. Unfortunately, that's about 68 MPH in my MM. Warranty's about up, so I plan to register a gripe, along with the rear view mirror that vibrates so badly on marginal pavement that it distracts me.

[Go Mifuni]

I have the same vibration in the steering wheel that is definately RPM related at about 2000. Unfortunately, that's about 68 MPH in my MM. Warranty's about up, so I plan to register a gripe, along with the rear view mirror that vibrates so badly on marginal pavement that it distracts me.
My mirror does the same thing but only since having my windshield replaced.

[RF Overlord]

My mirror does the same thing but only since having my windshield replaced.Heh...mine vibrated ever since day one UNTIL the windscreen was replaced...now it's fine...go figure.