Technical Need help!! weird ticking 1951 custom Buick Flxible 3 way

Ok the car is mostly gm, View attachment 4007055 350 crate th350 trans chevy truck rear end. Took it in this year for a ticking noise that seemed to be coming from trans area. When it first went in it would tick most notably at low speed from about 30mph down then gone once stopped, sound is similar to a lifter or exhaust leak tick but does it even with the engine turned off. if you put in neutral while it was doing it at that speed the sound would go away till you put it back in gear. So we put it up in the air and ran it in gear on lift and can't get it to make the sound. Seems to only do it when its on the ground, drivetrain loaded and rolling. In the process we pulled the trans pan found some metal in the pan and one of the valve body bolts laying in the pan,others were loose so I decided to be on the safe side and hoping something in the trans was causing it ( that was working fine before and after we fixed the bolts cleaned pan and filter and new fluid but still ticking noise) So we pulled it for a new Jasper built up trans(shift kit etc.) put it in and now the ticking is louder the before. So we started to look elsewhere but it still loudest at the trans if you put your ear on the shifter which is a tall Gennie Shifter ( http://www.gennieshifter.com/gennie-original/ ) its loudest there. so pulled the shafts a two piece gm type with center bearing we towed it up to 30mph without the shaft, engine running and going thru gears no ticking. (but once again it's not loaded like the lift run then so who knows) So took the shaft to a well know professional machine shop and shaft factory that did find some burnelling on old joints so had all the u-joints replaced and shaft balanced trued etc. They said the center bearing was good so they didn't replace that. So put it back in and ticking is back.(I was so hoping that was it but no) We have used chassis ears all over and it still seems to be coming from transmission. Any ideas would help and may get me back on the road with some money left as the shop time is killing me. They are going to call Jasper today as they think it might be the trans also but it took a long time to get them to that point at 70 bucks a hr.

 

what would be turning in the trans when out of gear and engine off that would tick is my question if it's the new transmission, and so much louder since putting that new one in. If it was doing it running I would have thought Torque converter bolts or flexplate loose or cracked, but those don't turn even rolling with engine off.

 

Torque converter and flex plate turn with the engine even at idle in park.

Exhaust under load hitting something

My guess is flex plate is either cracked between mounting bolts

Is the back of the torque converter mounted snugly in the crank?

Some torque converters need a pilot bearing or bushing in the crank shaft

 

But does it even with engine turned off when costing down from 30mph and put ear on shifter and its coming from there still, With old trans it would go away in neutral when slowing from 30 I'm going to go drive it today to see if that is still the case with new trans,. Does the converter push forward under slowing load that could make the bolts hit but we have checked them twice they seem tight and plenty of clearance on the lift when running

 

Speedo cable?

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I think it’s the flex plate too. Sounds like it has a crack in it. Bolting it back down after the tranny swap changed it enough to make the sound different but it’s still there.


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3x, cracked flex plate (usually right around the flange), hard to see.

 

Center hanger bearing. This seems to be the only thing not changed so far. I would have thunk that someone would take a good look at the flex plate while it was apart.

 

I've had full wheel covers make that sound.

 

NOT the flex plate guys. Reread the postings and see if you can figure out why it isn't.

U-Joint?

 

I been pushing flexplate also since day one myself so much so I been carrying a new gm flexplate around with me the only that stops me is why would it do it with engine off and rolling. But my guy also the one that put trans in still dont think that's it. I have no cover over it and they have pushed the converter back and looked they say it's fine. I cant believe they didn't check flexplate when the tranny was off for cracks or loose bolts but I don't think they did at this point either. The center bearing well the shaft shop said it was good and I have spun it and looked at it myself a couple of times and no roughness or sound even had chassis ears on it and the sound is hardly heard there. I think the ears are sensitive enough to pick up the noise from the tranny area a little.

 

Okay, I reread the first post.
I still think it’s the flexplate.

The op thinks the flexplate doesn’t spin in neutral. It is connected to the crank. It is always spinning if the engine is running.

They crack with little hairline cracks that are sometimes hard to see. Checking the bolts for tightness doesn’t tell you if you have a crack. They crack in between the bolts, causing a harmonic ticking sound as the flexplate rotates.


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Read Post #2 and #4.....

 

Dang!!!!!
I should have read past the first post!!!
Thanks for pointing that out!!!


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Since you have replaced the tranny we can rule it out

Could the trans be hitting someplace?
Shifter or shifter cable?
Exhaust ?


Sounds are a killer, chassis ears are a great tool but sometimes they can send you on a wild goose chase
As they only pick up resonance and not the actual sound
The sound could be coming from someplace else and is just loudest at that point
I’ve been caught a few rimes with noises


On a cat wheel loader sounded 100% like the front 1/2 of the drive shaft to me, customer and there on site tech
Pulled the shaft it was perfect, drove the unit with no front shaft noise still there, ended up the crown and pinion were chipped causing a tick.

My point is never mind what it is, try eliminating what it is not


Can you remove the shifter and drive it?
Any place the exhaust is close to the frame or body isolate it with some rubber
Check your cross member, tranny mounts , engine mounts
Shifter cables, tv cable ( if you have one)
Look at you air filter could it touch the fire wall under load
Stuff like this
Bad weld on the frame under stress while driving
Etc etc

 

if i am reading this correctly the carrier bearing and housing is the only part not replaced yet. might try that...

 

Ok just took it for another ride so before with old trans it would stop ticking when you put in neutral when its doing it slowing from 30-35mph. Now with the new trans it does it in neutral also. Still does it even if you turn off engine at that speed even in neutral, but it seems to stop a little sooner and the ticking seems a slightly more erratic as slowing. I am going to change the flexplate anyway and make the shaft shop change the center bearing but I really doubt it is either of those. Is there something in the back of trans like a bearing or (rear pump? but I dont think they have one) or something else in a th350 trans that the shaft would still be turning to make the tick?, as trans are not my thing. If their bad or funny acting I just change them lol.

 

well no exhaust leaks checked that and ticks with engine off so that shouldn't be it. trans mount looked good and the trans clears everything on the car by alot as it's much smaller then the dynaflow that was original to the old straight 8. air filter is long way away from anything. The engine mounts they looked at and said were ok but I will have them check again, it does sound like a lifter or exhaust leak but once again ticking when engine off and coasting in and out of gear so they are out I think. probably eliminates the mounts too at that point. If its the pinion in the rear well I'm not hearing it with the chassis ears and its loud enough to hear 10 ft away now which before the trans change it was half that loud at least. The ticking is a to constant and regular for a frame issue and this has a frame like a tank and looks very good as it was a frame off job about 10 years old with only about 11,000 since it was put together. Even that old tranny was a custom build then but I won't be using them again for sure after find bolts in the pan.

 

Speedo cable has also been suggested, but that's not load sensitive. Nonetheless it's easy to unhook your speedometer cable at the transmission and see if that makes a difference.

 

I will do that that had occurred to me also just haven't had a chance to try it. thank you

 

I will be on that in the next day or two as soon as I get the shaft pulled again as they were supposed to do it. They will change it for free now and apologized as one worker thought the other had done it they claim while they waited for a special conversion joint to arrive.

 

I'm voting for speedo cable. It's about all that's left that hasn't been changed, or looked at at least.

 

Would be nice and that will be tried but I think we would have heard that when on the lift tires free and running drivetrain thru gears and simulating 30mph slow down. When its on the lift running we cant hear the ticking, I would think the speedo would still do it then if that was the case. But anything is possible at this point.

 

it's the governor.

 

I am betting it’s the exhaust system. They commonly ‘tick’ with the engine shut off after having been driven or least brought to operating temperature. In addition, it is at least possible that the ‘loading’ of the system from engine torque when in gear or driven also changes something, like a joint in the exhaust system or an exhaust hanger, etc. creates another similar sound, but is not the sole source.

Ray

 

Could there be an issue with the slip yoke fit at the transmission?

 

Does this car have a stereo? If so, crank that dude up!!

 

I had a noise exactly like that just before the right front wheel bearing let go. Swore it was a speedo cable.

Adam


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The ticking happens even with the engine turned off and in neutral while slowing from 35 like something in the back of the tranny is still rotating and making the noise. So flexplate would be out I feel

 

I just put new front bearings and hubs in the front last fall and have checked them already again just in case.