I have a vibration that I can feel through the steering wheel, driving or not, and when I put my hand on the engine. I had this vibration in the previous engine, after I blew a head gasket (burned through between two cylinders, engine rocked violently). The vibration was not there before the head gasket blew.

After the head gasket blew, and after replacing the head gasket, I had noted that the motor mounts and the tranny mount suffered some damage from the engine rocking, I replaced those but the vibration was the same - most noticeable when I'm revving the engine between 1200 and 1600 rpm range. There was also damage to the tranny rear bushing, replaced that (from the tranny being cock eyed, straightened that out when I replaced the tranny mount).

When I pulled the engine apart, the rear main bearing was destroyed. I had the crank checked out, journals repaired and the the crank balanced. The shop said the bores did not need align honing, they were dead on specs. Rebuilt the engine, during break in I still have the vibration. I had replaced the rods, pistons, cam and bearings in the rebuild.

Assuming it is NOT the engine, what in the transmission could cause a vibration like this, I can feel the vibration with the car in PARK, in the garage when revving the engine. Torque converter? Pump?

Anyone have such a vibration that was due to the tranny?

Brian

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It happens to OE lock-ups for sure, the clutch assy. gets off center or the
hub worn/damaged, and you gots vibes that don't go away.

I took the car to a drive line shop while it still had the old engine in it... the guy there took it for a test drive and swore it was the engine, "...couldn't possibly be the tranny." His reasoning was that if it were the tranny it wouldn't be rpm dependent, therefore is must be the engine. Fast forward to a newly rebuilt engine, same vibration...

Brian

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Are you talking about the torque converter? Are '67 slant A904 "lock up" type? Just wondering if I should try a new/different torque converter first...

brian

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Is there a single type of torque converter for a '67 dart, SL6, A904 or are there several types. What do I look for teeth #, diameter, spline count, pilot shaft diameter, what are the parameters so I know what to look for?

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No lock-up for that year unless someone swapped it, but the TC and some of
the internals are the only other things turning w/the eng. all the time. Flex-
plate straight?

I don't believe there is more than one ring-gear dia./count, so any for that
year just to try should be fine if the entire unit is '67, I suppose the input shaft
could get damaged/bent, it is the smaller one. Double check the runout of
the hub reciever in the crank?

Don't let's be loading stuff into this question that doesn't belong. NO, the torque converter is not a lockup type. NO, someone did not swap a lockup torque converter into this transmission (which cannot be done). NO, lockup converters with worn clutches do not cause a vibration in park/neutral. That doesn't mean the torque converter isn't a suspect—it is, because it's the most massive thing that rotates at the engine's same speed. But talking about lockup converters is taking off down a road that won't go anywhere useful here. It is possible the torque converter is faulty or imbalanced. You say the vibration occurs when you rev the engine in Park—your driveline guy is probably correct that this rules out a transmission fault causing it, though it does not rule out an imbalanced torque converter.

You say the vibration didn't exist before the head gasket failure. That's another reason why guesses about lockup torque converters aren't helpful, but it suggests, as you surmise, that the rock-and-roll action of the misfiring engine might have caused some problems. Difficult to imagine how a faulty head gasket would throw the torque converter out of balance, but don't get locked into a rigid line of thinking that it MUST be this or it MUST be that. Old cars can (and often do) have multiple things wrong with them at the same time.

Please describe this vibration in more detail. What is its approximate frequency? Does its frequency change with engine speed, or only its amplitude (intensity)? Can you see the engine shaking in time with the vibration you feel?

Please describe (in close detail) your left, right, and rear engine/transmission mounts. How old are they, what brand are they, where did you get them?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Ahhh, I sensed a bearded disturbance in the force, lol! All good points, I used
the lock-up as a "for instance", that eng speed vibes are poss. from the TC.
I didn't realize the OP was that unsure of his driveline components. No, you
can't swap lock-up converters, but you could entire trannys, but not on '67 &
down cranks.

OK then, 1) The damper was OK/undamaged, slipped, checked for TDC ?
2)The crank was checked for twist,each pin exactly 120deg.?
3)Sure you don't have ign. crossfire issue?
4)Which two cyls. and what caused the rear main damage?

Crank history: The crank was checked, journals resurfaced, balanced, by a shop, so I assume that's OK (for now), I didn't notice any signs of scraping in the crank hub.

Peripherals: The damper checked out, the timing mark aligned with TDC (it is a newer aftermarket unit). The flex plate seemed pretty straight, no cracks or any signs of damage. I don't think that I have a cross fire situation, I had run through the wires, cap, rotor, distributor, no signs of arcing or cross talk. The gasket burn through was between #4 and #5 if I'm recalling correctly, I had a lean mix issue. I had enriched the mix, adjusted the carbs prior to the rebuild, the vibration was still there. I had changed the wires, cap, rotor, distributor, coil, ECU, during the vibration issue, no change (points me to mechanical issue, but not definitive).

Mount History: The engine mounts were stock, spool type (I have the 73-76 k frame setup) and the tranny mount was stock type. The history was that there was no vibration, I blew the head gasket, the motor mounts and tranny mounts showed signs of damage but were not unusable by my estimation. After I straightened out the tranny (it was cock-eyed, pulled to one side, mount slipped off rubber about 1/2"), before changing out any mounts, this vibration was apparent. After fixing the head gasket, lean mix the vibration persisted. Then, I changed the motor and tranny mounts, same result. I used polyurethane mounts, the engine ones are pretty soft, the tranny one is stiffer. I know some folks have vibration issues with poly mounts, other's don't; given the above history, I don't think it's the mounts.

Tranny History: original tranny, A904, I had it rebuilt 3-4 years ago when I bought the car. No history of problems until I blew the head gasket. The side ways position described above, and the tail bushing was torn up (undoubtedly from being cock eyed). I changed the tail bushing, the output shaft didn't appear bent, seemed centered in the hole (measured with micrometer), but I wouldn't be able to discern a bend in the few thousandths range. I have never had the tranny apart personally, but I did install a deeper pan/filter kit. I've never pulled the torque converter. BEFORE, I noticed the cock-eyed tranny there was a periodic stronger vibration (in retrospect, the current vibration was likely there as well, I just didn't notice it due to fighting the bigger one). Then, after i straightened out the tranny and replaced the tail bushing, this current vibration was apparent. I also changed out the driveshaft, that made no difference (the vibration occurs when I'm in park anyway...).

Vibration: Dan, the vibration is pretty low level, not a violent shake or anything, but I can feel it both in the steering wheel and when I was doing the break in, I can feel it in the engine. Not science, but my sense is its emanating more from the rear of the engine, which makes me suspect the torque converter (assuming the crank balancing/repair was good, the shop guy showed me the balancing numbers, he said the rear was "perfect" and the front was 0.5g off but within specs, from that I'm assuming it's not the crank). I changed the rods and pistons, and since the vibration appears identical to before the rebuild, I assume it's not the internals). It seems to be regular in period, amplitude rises in the 1200 to 1600 rpm range, seems to reduce again in amplitude as I get closer to 2000 rpms. It might be there at idle, it was before the rebuild, but I've not adjusted the idle on the new motor yet, my data is only from break in rpms.

Assuming I want to pull the torque converter and try another one. Do I need to drain the tranny to do this, i.e. when I pull the converter does fluid come gushing out?

Brian

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You'll surely want to drain the torque converter -- it has its own drain plug, accessible via the inspection plate at the bottom front face of the bellhousing.

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Too many people who were born on third base actually believe they've hit a triple.

I wonder if I could see anything in the fluid, just by draining the converter...maybe there would be bits in there that might indicate damage.

It would be difficult to refill the converter without it being out of the tranny, so if I'm going to drain it, I might as well pull the tranny - fair statement? I suppose that is academic, I plan to pull it anyhow, as a positive result, stuff in the converter's fluid would mean I'll try another converter, and a negative result, wouldn't sway my plan to try another converter anyhow...

Brian

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Sorry, Dan, I didn't answer all your questions. I can't really see the parts vibrating, feels like the movement is 1/8" or less even, but very noticeable by feel.

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Remove all belts off the engine and run it briefly to see if anything changes. Could be related to fan (bent) or other accessories.

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1976 Feather Duster /6 4sp
1984 W100 318 727 np241
1972 'Cuda 340 4sp
1985 D250 360 46RH

Hmm, never tried that, sounds like a good test...will let you know. They sure look straight and true when rotating, but you never know....

Another thing I can do is (with ear plugs) unhook my exhaust at the end of the Y collector and see if the vibration goes away. I don't think it's the exhaust, but you never know....it's not been reconfigured since before the vibration started, but with the engine jarring and such, perhaps its bound somewhere. I've had it on and off a number of times though, doesn't seem likely it's that.

brian

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