schlop clop noise and continuing shudder


Oct 9, 2023
Vehicle Details
'96 Bird 4.6
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My <98k miles Bird is producing a slow rate clop schlop schlop clop sound when RPMs go low under load (e.g., in drive at a stop light). No noise in neutral or park and I don't hear it upon acceleration (RPM increase). There's no pinging, scraping, whining or whirring sound as if metal on metal. I can try to catch it on my phone if you need audio, but last time I tried (older phone, crummier mic), the noise was drowned out by the engine noise and the mic didn't pick it up well.

It doesn't do this until the tranny is warmed up. If I sit on the driveway with it cold and put it in drive with brakes applied, no noise. Drive it a couple miles and the noise is there when I'm stopped at a light.

I did the shift shudder TSB Mercon V swap out, including TC, a while back, BUT I didn't change it again after around 5-8k miles as recommended, and I still have shudder, which is the second issue at the moment.

There's no CEL or tranny codes on my scanner. Dipstick shows correct level, good color, no grit and no burnt smell. Nothing to suggest overheating. No hesitation on acceleration or other probs besides the old shudder.

1. Does this sound like it might be an early warning that the tranny pump is going?

2. Do you suppose doing another Mercon V change will at least eliminate the shudder at this point, or are my friction rings goners? I'll probably do the change anyway, since I already have all the Motorcraft fluid in my inventory, just wondered whether you've had success eliminating shudder after the 2nd fluid change when the 1st change didn't cure it.

3. If I still have shudder and schlop clop after the 2nd fluid swap, do you suppose adding friction modifier might help with these issues or am I past that point and it's time to kiss this tranny goodbye and install a rebuilt? I hate rebuilt parts, as I've had so many probs with them over the years. Almost nobody does it right. Alternators, a/c compressors, calipers, you name it, I've gotten shit quality rebuilts and had to swap them out again immediately. I hate to think of the probs I'll have with something as complex as an auto tranny, but if mine is done, I guess I'm SOL and will have to swap it.
Probably unrelated, but I'll share in the spirit of eliminating all possible causes:

I had a noise which only occurred in Drive at a standstill. It was a low tone tapping sound from the transmission.
After months of unsuccessful guesswork, I finally found that it was an O2 sensor connector (left/aft). The sensor wire is held by a clip to the transmission, but it was routed in such a way that the connector touched the underbody. That in combination with some normal transmission vibration in Drive at a standstill produced the tapping noise.
A zip tie later, the noise was gone.

Can't hurt to check.
an O2 sensor connector (left/aft)

That would be a welcome stroke of luck. I'll definitely check for external things rattling, but I have my doubts, as this sounds "heavier" and "deeper" than a connector tap tap (I've heard and secured those in various locations before).

Another thing that occurred to me is perhaps tranny mount. Maybe it wouldn't be noticeable at higher RPM when the engine smooths out (less vibration in my Bird's case) and the engine itself is noisier, possibly drowning out the clop noise. I'm just assuming the clop noise stops with higher RPM under load, because I can't hear it, but I guess it could still be present.
edit: On 2nd thought, tranny mount probably wouldn't be temperature dependent, so I guess strike that idea.

I neglected to mention that the clop noise also vanishes when I press the accelerator pedal in drive while holding the brakes, so all it [apparently] takes to kill that noise is for RPM to increase a little, regardless of how/why it increases. I would expect things to get worse with a worn pump the more load that's put on it, but 🤷‍♂️.
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I'd check the engine mounts and trans mount. Look for things that could be moving around.

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