If you have a little time and want to give me a hand

[GOPAPA]

in why my car is making these ratting sounds ,, I am wanting to get it road worthy and sell it ..

I start up the car (1939 Chevy ) 235 cu in motor-- 5 speed T-5 tranny --1955 Bel Air rear end ,,and it sits there rattling with a sound like a throw out bearing going out..when I shift it rattles and after I shift it rattles .,while driving ,,,worse in lower gears than the high one like the 3RD and 4TH

I decided to have the car hauled to the Machanic Trans shop instead of driving it and taking the chance of it breaking down along the way.. ,,,So the Machanic took the transmission apart and found nothing wrong with it ,,,,,,,,,,,( I had reservations because my son and I overhauled it),.. he puts a stethascope to the motor area and also the rear end ,,no harsh sounds ,,but at the fly wheel area there's where the rattling sound is coming from .

The machanic wants me to do some things like jack up the transmission and put something like a 1/4 inch leather or hard rubber shim between the transmission and the cross member for the transmission.. next take the bolts out of the crossmember under the bell housing and take down the cross member..

Then he says start the engine and see it this stops the rattling sound .. He showed me how the motor mount rubbers were worn to where the motor metal is sitting right on the cross member that the mounts are on.. he thinks the sound may be traveling to the bell housing area along with the bell housing mounts also are worn too..

Now I want to make clear ,,this is a harsh rattle like a sound of a bad throw out bearing as for what I can compare the noise too.,the throw out bearing is like new

[67C10Step]

Cracked flywheel? Just throwing out an idea. Could be one of the mounts the guy pointed out as well. Worth a look but I am just a few minutes south of Idaho.

[geezer#99]

Does it rattle when you accelerate?

[starterman99]

When the mechanic had the trans out did he pull the clutch and inspect it or the pilot bushing or bearing?

[Boog]

Does it continue to rattle with the clutch depressed?

[Sheepdip]

I'll give you $5k for the car and you can forget about the rattle.

Seriously though ....I'm no expert by any means, and have no idea what the tranny is out of, but I believe those 5spds sourced from S10's had this big 4x4 steel heavy block hanging on the tail shaft which was for vibration I was told.

[GOPAPA]

Originally Posted by 67C10Step

Cracked flywheel? Just throwing out an idea. Could be one of the mounts the guy pointed out as well. Worth a look but I am just a few minutes south of Idaho.

I looked up a cracked fly wheel on the internet and it sounds exactly like what the noise that mine is making .. I am going to have to get the car jacked up and take off that inspection plate and look for cracks..

After rebuilding the transmission and installing it ,,and while test driving I did hear one big noise like a "SNAP "! that might of been the fly wheel breaking.??...

thx .. for this idea 67c10Step

[GOPAPA]

Just to clarify ,,I do have a flywheel and not a flexplate.. and flexplates are the ones most likely to crack and break ..

[Steeveedee]

Yeah, if a flywheel breaks it's usually a little more catastrophic. My dad knew the guy who was the cause of a redesign on the floor of '57 Chevies after he got in one with fuel injection, wound it up and the flywheel broke. It laid a part of the floor pan over his foot and kept the accelerator pedal all the way down. Finally figured out enough to shut it off. I had a friend with a '55 Chevy. We were cruising Van Nuys Blvd one night and he got into a race with a Nova wagon. He shifted into second and started losing ground, so he slammed it back into low (no synchro- it made quite the noise!) and pulled it up to whatever that Corvette engine would rev. Knowing about that exploded flywheel, I slid my feet back to the seat to avoid shrapnel. But it held. I don't remember who won that race, I was busy watching my feet.

[GOPAPA]

Originally Posted by Steeveedee

Yeah, if a flywheel breaks it's usually a little more catastrophic. My dad knew the guy who was the cause of a redesign on the floor of '57 Chevies after he got in one with fuel injection, wound it up and the flywheel broke. It laid a part of the floor pan over his foot and kept the accelerator pedal all the way down. Finally figured out enough to shut it off. I had a friend with a '55 Chevy. We were cruising Van Nuys Blvd one night and he got into a race with a Nova wagon. He shifted into second and started losing ground, so he slammed it back into low (no synchro- it made quite the noise!) and pulled it up to whatever that Corvette engine would rev. Knowing about that exploded flywheel, I slid my feet back to the seat to avoid shrapnel. But it held. I don't remember who won that race, I was busy watching my feet.

I have heard of clutches breaking thru the floorboard ,,just never flyweels,,

I worked with a guy years ago that bought a brand new Chrysler and it wouldn't start every time and had to push just a few feet to make it work..and he found out that the fly wheel was out of round and it got stuck on the starter..

[special-K]

As far as the mechanic's suggestion with belts and such, why didn't he just install new mounts? Why don't you start there, since they are all worn and need replaced anyway. Even if you still get the noise, you have eliminated that possibility and the care is better for the sale.

In a '95 Chevy diesel I had a DMF crack and it sounded like a rod knock. GM says DMF stands for Dual Mass Flywheel, but I say DMF stands for who ever came up with that dumb idea! It took a lot to convert it to a solid chunk of steel that I have never seen fail

[Steeveedee]

Originally Posted by GOPAPA

I have heard of clutches breaking thru the floorboard ,,just never flyweels,,

I worked with a guy years ago that bought a brand new Chrysler and it wouldn't start every time and had to push just a few feet to make it work..and he found out that the fly wheel was out of round and it got stuck on the starter..

In all fairness to my memory, it may have well been the pressure plate. I heard the story when I was young. My dad worked at that plant in Van Nuys in those days.

['63GENIII]

Powerstrokes were notorious for the springs in the dual mass flywheels weakening or cracking causing a rattle that sounded like a box of rocks shaking around. It would be especially loud as you would shut off the engine and the flywheel would rattle for a second or two after the engine was off.

The clutch plate also has very similar damper springs that run the circumference of the clutch hub. Ive seen those crack and just flat out degrade to the point that they are loose and you can hear the hub, springs and friction rattle by hand when you take them out.

They would rattle anytime the engine runs, probably more prominent in the lower revs because the engine strokes are more defined?

Im gonna guess that as you let the clutch out, the rattle goes away for a bit only to return when the clutch is lightly loaded? On acceleration and deceleration does it pipe down?

The thought of a cracked flywheel is enough to make me pull the trans out just so I could sleep. Never seen one in person but know that blow proof bell housings are made for a reason.

My bet is on the damper springs on that clutch plate.

[GOPAPA]

Originally Posted by '63GENIII

Powerstrokes were notorious for the springs in the dual mass flywheels weakening or cracking causing a rattle that sounded like a box of rocks shaking around. It would be especially loud as you would shut off the engine and the flywheel would rattle for a second or two after the engine was off.

The clutch plate also has very similar damper springs that run the circumference of the clutch hub. Ive seen those crack and just flat out degrade to the point that they are loose and you can hear the hub, springs and friction rattle by hand when you take them out.

They would rattle anytime the engine runs, probably more prominent in the lower revs because the engine strokes are more defined?

Im gonna guess that as you let the clutch out, the rattle goes away for a bit only to return when the clutch is lightly loaded? On acceleration and deceleration does it pipe down?

.

My bet is on the damper springs on that clutch plate.

thx for your imput ,,

Would you also think that the SNAP sound I heard and then the NOISE I now hear could of been the damper springs on the clutch plate breaking ??

['63GENIII]

Originally Posted by GOPAPA

thx for your imput ,,

Would you also think that the SNAP sound I heard and then the NOISE I now hear could of been the damper springs on the clutch plate breaking ??

Anything is possible. The mechanic tracing the sound to the throwout area is encouraging. Its really close to the hub and springs.

I always like to think its something simple. Hope that's the case with your car too.

I would be curious is the noise is constant under acceleration and deceleration vs cruise (light load) or even neutral.

[special-K]

When the snubbers went out on the DMF in my '92 pressing the clutch in quieted it. It sounded like the throw-out bearing, but when it's that the noise happens when peddle is depressed. The throw-out is just floating while driving. So I went in expecting to find the front bearing bad, not knowing anything about the dumb mother... I mean dual mass flywheel. Not really unrelated. Hopefully adding some perspective.

The mechanic would have seen issues with the throw-out bearing or if it the fork was messed up. I would think he would have inspected the pressure plate and clutch disc, even before going into the transmission.

I'm somewhat doubtful of this mechanic. I don't get how he would hand your car back telling you to try adding temporary bushings to check for vibration broadcasting when he had the transmission out, went into it, and re-installed. What in creation would he not have simply replaces those gal dern mounts??? I just can not grasp that.Sounds like the load of crap the GMC dealer tried handing me when my truck went in for issues under warranty. "We couldn't get it to do that", I heard on a couple different issues. "Well, it does it for me and it needs fixed!" Another story for another day.

[GOPAPA]

Originally Posted by '63GENIII

I would be curious is the noise is constant under acceleration and deceleration vs cruise (light load) or even neutral.

I drove it home ,,with fingers crossed that it would make it ,, in traffic too.. so I can not really come up witih any thing other than in higher gears the rattle was less.. I am going to have to put the car on hold until a week or so and also after I talk the machanic into putting the car back on the hoist and taking the drive line out ,the transmission out and then check out the clutch springs.. he is a petty good guy ,he ((just)) does transmissions ..

Originally Posted by special-K

When the snubbers went out on the DMF in my '92 pressing the clutch in quieted it. It sounded like the throw-out bearing, but when it's that the noise happens when peddle is depressed. The throw-out is just floating while driving. So I went in expecting to find the front bearing bad, not knowing anything about the dumb mother... I mean dual mass flywheel. Not really unrelated. Hopefully adding some perspective.

The mechanic would have seen issues with the throw-out bearing or if it the fork was messed up. I would think he would have inspected the pressure plate and clutch disc, even before going into the transmission.

I'm somewhat doubtful of this mechanic. I don't get how he would hand your car back telling you to try adding temporary bushings to check for vibration broadcasting when he had the transmission out, went into it, and re-installed. What in creation would he not have simply replaces those gal dern mounts??? I just can not grasp that.Sounds like the load of crap the GMC dealer tried handing me when my truck went in for issues under warranty. "We couldn't get it to do that", I heard on a couple different issues. "Well, it does it for me and it needs fixed!" Another story for another day.

Tim ,I agree with on all points you made.. back when I was 18 ,,I changed out the preasure plate and clutch on my 39 I had then and I know I can do it again ,,as this time I do not have to drop the rear end,, ( no closed drive line in this one ) so, if the guy will let me work with him or at least watch ,,I am hoping he will take it all apart and put in a new clutch plate and preasure plate .. I feel almost possitive it has to be the springs in the cluch plate,,as the sound is just like what 63GENIII says it is ,,plus Y-tube video also is what It sounds like .. ( my problem is I have no one around me to lift the tranny up into place and also that car hoist sure beats me have to work on my back under it on a concrete floor with pillows under my head. I took it out by self and so I am not wanting to put it back together..

By the way are the bolts to hold the flay wheel in supposed to be tightened to 60 lbs ? seems that was what I did way back when?

[Axle]

Hows the starter setup on that car? Same as the trucks? I had a starter that eventuallyt started bouncing the pinion end retainer on the flywheel making a random rattle. Might throw a thin shim in and see if the rattle goes away.

[GOPAPA]

Originally Posted by Axle

Hows the starter setup on that car? Same as the trucks? I had a starter that eventuallyt started bouncing the pinion end retainer on the flywheel making a random rattle. Might throw a thin shim in and see if the rattle goes away.

Another idea,, i thought there was none left ,,thx

Would this problem you say that the starter is boucing the pinion end retainer still make the rattle even after the starter disengages from the fly wheel?

[Axle]

Absolutely. While the engine is running. Thats what the old worn out starter in my old winter beater 76 nova with a 250 was doing. Up in the air with the flywheel cover removed you could watch everything shaking and make contact with the flywheel momentarily creating the rattle sound. Started off very randomn, and obviously got to the point where up in the air trying to find it (and checking flywheel, hence the flywheel cover removed) starting it up for a listen and bingo as they say. Only experienced it once on that car. I think it was only virtue of the fact it was up in the air and running that we finally located the sound. Changed starters and all was quiet again.

[GOPAPA]

Originally Posted by Axle

Absolutely. While the engine is running. Thats what the old worn out starter in my old winter beater 76 nova with a 250 was doing. Up in the air with the flywheel cover removed you could watch everything shaking and make contact with the flywheel momentarily creating the rattle sound. Started off very randomn, and obviously got to the point where up in the air trying to find it (and checking flywheel, hence the flywheel cover removed) starting it up for a listen and bingo as they say. Only experienced it once on that car. I think it was only virtue of the fact it was up in the air and running that we finally located the sound. Changed starters and all was quiet again.

I put in a new starter and unless what you say can happen after some time ,,then I guess I doubt this is the rattle.. because this rattle started after I put the rebuilt tranny in.. and the starter was put in before that..

[Axle]

I didn't see anything about a new starter in the OP, I read it as a mystery rattle appeared first and the trans got r&r in the meantime.

[GOPAPA]

Originally Posted by Axle

I didn't see anything about a new starter in the OP, I read it as a mystery rattle appeared first and the trans got r&r in the meantime.

Didn't mean to throw you a curve ball about the new starter,,as it was new a couple years ago before I took the saginaw 4 speed out..I I only mentioned that because it was like new yet and not a starter that had been in the car for many years.. I plan on taking your advice about what you said that can go wrong with the starter all the same and appeciate your input.. your thoughts now give me two things to look for when I tear into it again.. clutch springs and the starter..

thanks again Axle I will let you and all know what it was soon as I can get it up on a hoist.

[special-K]

I wish I could offer better help. The only thing I wonder is, have you tried not shaking your head over this matter? If so, did the rattling stop?

Sorry my friend. I know it's not a funny to have this problem. But sometimes joking helps, even if it doesn't fix the car. I've racked my own brain on this enough to make it rattle some

[GOPAPA]

Tim.. thanks .. I do have a couple leads to go on from guys on this forum ,,so this coming week I am going to dig into and get it done.. thx to you guys too..correction ,,it will be the later part of the month ,,I plan on it anyway