Topic: "Knocking" noise ideas/diagnosis -- VIDEO inside! ***SOLVED w/ DAMAGE!!!***

[jphillips3333]

A couple of thoughts ... I'm not a transmission guy but my ex-father-in-law is (if that means anything).

Fluid level - check in park at operating temp.
Does it make the noise in gear while stationary?  If it doesn't, the transmission gear train should be OK.
Is there fluid in the line at the vacuum modulator?  Bad diaphragm?
Is the line steel down to the vacuum modulator with a little bit of rubber?  Rubber cracked?  You need good vacuum.
Have you dropped the pan?  Changed the filter?

Changing pressure to the vacuum modulator might also point to the pump ... I think that's rebuild time.

If you rebuild the tranny and do your own R&R, you HAVE to blow out the lines.

[OrigOwner77]

Fluid level is good.

Noise in park/neutral AND in gear while stationary. Goes away with the modulator vacuum line unplugged at the carb though.

Haven't pulled the line at the modulator yet.

Line is rubber all the way from carb to modulator -- same as the '77. Line is thicker rubber tubing, not cheap thin stuff. Going to replace when I check the line for fluid though.

Pan drop and filter change were done 4-5 years ago after I got the car. Car doesn't get driven that many miles per year, and fluid still is clean and bright (not dark/burnt smelling).

[jphillips3333]

Just a thought, if you're going to replace it anyway, you may want to get a hard steel line from the base of the modulator to the around the back of the intake.  You need good vacuum from the intake down to the modulator - a couple of inches of rubber hose each end.

This may not fix your problem but has ALWAYS been the way my automatic transmissions were setup.  Prevents the hose from collapsing on itself, cracking, burning, etc.

Looks like 3/16" stock, you could probably bend it yourself.  Who knows, parts store might carry it - I've never had to replace one.

[fireman_033]

  If you increase the rpm the same amount with the vacuum hooked up does the noise go away??? You did say it goes away with rpm right?  Scott

[OrigOwner77]

Yeah it, as far as I can tell, goes away with increased RPMs. Though with true dual Flowmasters & headers, the sound of the 400 drowns most things out. 

[OrigOwner77]

Bumpin' this back up for an update!

Had a local shop check the car out and do an alignment....asked them about the noise. Low and behold, the noise indeed had to do with the flexplate bolts (I assume going to the converter). They weren't loose...but rather two of them didn't have washers. I guess this in turn made the threads longer and when all the bolts were snugged, caused the noise.

All fixed now though. Thanks for the ideas everyone.

[Eagle 1]

Good deal.

[OrigOwner77]

Posted this over on TAC, so I may as well give the update here too: (posts copied from TAC and edited for relevance)...

***ANOTHER UPDATE*** (Damage Report)

Shop just called...while removing the old ball joint, the mechanic (according to the shop mgr. who I've been dealing with) put an "approximately 2 inch dent in the fender. I was admiring your beautiful car while it happened and it made me sick to my stomach." :evil: :evil: :evil:

He said he'd cover any/all costs....which I would expect....but ****...just adds insult to injury, especially since I have a couple small local car shows coming up in the next two weeks. :lol: Such is my luck. I swear the car is haunted/possessed with everything that it has done to me over the 5 or so years I've had it. On a positive note, he mentioned the local F*rd dealer collision shop right by them does good work and he can have the car done in a day or two for me (and not have them half-@$$ it/rush it). He offered to keep the car locked inside and take it to them tomorrow morning when they open...but I'm bringing the car home tonight to take pics and will take it to the collision shop WITH the Manager tomorrow morning...that way I know the "before and after."

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I'll have pics up this weekend. Dent is at about 10:00 or 11:00 on the front pass. fender wheel-well. It's small (inch or two indent, and below it the sheet metal actually pops out slightly), but is right at the lip. Shop says it'll take 2 days to do the job properly (between bumping it out, paint, curing, etc). Looks like I'll be taking it in Tuesday. Now I have to figure out if the car has the '79 gold decals on it or the '80 gold decals, as they'll need to replace the "TRANS AM" decal on the fender.

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make sure they paint the whole fender and not just blend the paint around the repair.

I do know that the decal has to come off, along w/the body-side molding. I *think* they're going to blend/feather the paint, which is totally ok with me at this point. The pass. side of the car is in the worst shape (door has a vertical indent/crease, roof-line weld cracked the paint slightly, pass. fender has a few other odd nicks, etc. Plus the paint is flaking in some inconspicuous spots on the nose due to past bad prep work. A repaint is certainly in the car's future (maybe in a couple years), so for now, this is acceptable in my opinion. However, where they pointed out they'd do the repair/paint was a good portion of the rear of the fender. They're not just going to hit the dent/ding with paint and call it a day at least. They can't, with what they're going to remove from it. Removing the molding alone will likely pull paint...probably the same w/removing the decal. To me it sounds like the rear half of the fender will probably be worked.

[rhino33]

I have used an experienced paintless dent repair specialist twice in 3 years , he has saved me thousands, you would never know there was a dent after he`s done.might be something to look into

[OrigOwner77]

I have used an experienced paintless dent repair specialist twice in 3 years , he has saved me thousands, you would never know there was a dent after he`s done.might be something to look into

I appreciate the info.

[pointman]

Wow! You've had some trials with this repair, it's never simple for some reason. Good luck with the bodywork, hope you don't miss the car shows on your side of the State.

[ta78w72]

A paint guy told me that the two colors they can't blend are black and red.  They just paint the panel that needs it.  Let us know how they fix yours.

[OrigOwner77]

Will keep you all updated.

And I'm not missing the car shows -- I know that much! The "Trans Am" decal on one side may miss the shows, however. LOL. Depends how soon I can install after paint.

[OrigOwner77]

Photos: