Technical 53 Chevy - Beeping Noise when Stopping

Ok, I finally took it for a drive today.

After greasing both U-joints (I made sure I saw grease oozing out of the rubber parts) and changing the rubber hose ends on the vac line, the noise is unfortunately still there. It sounds the same but this time it took me driving for about 30 minutes before hearing it. The first 25 minutes I was excited I didn't hear anything. Everything felt great, engine temp was perfect, speedometer was working and I passed one of the signs that indicate your speed and it was spot on. The turn signals and cancelling cam worked and the brakes were stopping the car nicely (I mention these things because I had other threads on some of these issues).

I noticed there is a screech noise when pressing the brake pedal but only between a certain segment of the travel (not initially and not past roughly 1/4 of travel). I'm thinking maybe this is from grooves in the worn out backing plates on the rear end.

The only thing I can really do is to maybe replace the 3/16 brake line the previous guy used for the vac line and use 1/4" since the vac line is 1/4" and the trans modulator and intake have 1/4" fittings. I would imagine hose clamps should have sealed this fine but I don't know how much vac a th350 trans operates on?




Here are some photos from my drive today.






I have 3 weeks off before I start my new job so I can put it back on jackstands and take wheels off and look at the brakes. I can also replace the 3/16 line for the trans vac with 1/4 if anyone thinks I should? Not sure if that would be a waste of time.

Other than that I'll have to take it to a shop that may have an experienced mechanic that might know the old stuff.

 

Forgot to say I can almost swear the noise I hear when the trans shifts from 2nd to 1 seems to come from the passenger side but hard to say 100 percent. I might recruit a friend to stand on the side of the street and see if he can help pinpoint the location a little better.

 

Hell, could be a pressure build up in trans blowing down each time your doing that said throttle pressure.

But since your thinking brakes, let me make this easy on you.

Get rolling, put it in neutral, then let motor come down to idle, or even turn it off, then hit brakes, if its brakes it will show its face right then and loud and proud.

If that doesn't do anything, then I would see your modulator on the side of the trans is leaking down vac. spray a little soapy water around the outside fittings around it and the base, blow into the hose and see if it bubbles. Just a few old tricks my grandfather had given me before he died. I've never done the modulator test but have heard it worked for someone who had a split o ring.

 

Put some Bulls**t in the trans. Otherwise know as additives, just in case it has a 'squack' due to hard seals.

I think by now I would have taken it to a trans shop and asked for their thoughts. They know, if they are reputable every sound a trans like your is likely to make. Would have saved you a LOT of time and effort.

Course its JMHO

 

Thanks, I had tried putting it into neutral while driving and not touching the brake pedal and it made the same exact noise right when I switched from drive to neutral. Someone said it could still be a drum that is locking up and releasing but I think it's transmission related because it happens when slowing down and right when I feel the shift from 2nd to 1st.

It happens after 25 min of driving and to me it sounds like it's coming from the passenger side but can't tell if front or rear so probably in the middle where the trans is. Maybe once the fluid heats up there is pressure buildup. Maybe it's the modulator indeed. I can try the soapy water test! Thanks

 

Yup I'm pretty sure its trans related.. The shop that sold me the rooster comb will probably be able to help. I will try the vac modulator test with soapy water suggested by StubbsRodandCustom and if I don't see a leak I'll take it to them.

Thanks.

 

Thought I would post back one last time. I put a piece of rubber on the vac modulator and blew as hard as I could but there wasn't any leak anywhere. I replaced the 3/16" line with 6mm line for the vac steel line (NAPA was out of the 1/4" stuff) and new rubber ends.

I replaced the front brake pads (under warranty) even though I put maybe 100 miles on them max and greased everything really well. One of the shims on the old pads was slightly coming off.

I just took it for a drive and there was no screeching noise at all when touching the brake pedal like last time. GREAT. However after 20 min of driving the beep noise came back when it shifts from 2nd to 1st when slowing down. I stuck my head out the window and I could swear it sounds like it's coming from the front but so hard to say 100 percent.

I tried going uphill and letting the car slow down on its own without touching the pedal and the noise comes in when slowing down and the shift from 2nd to 1st.. sometimes it's hard to tell when exactly because the trans shifts really nice and smooth.

Last thing I did was put it in park and neutral and gave it some gas slowly and then let it come back to idle slowly and I did not hear the noise.

The only vac line I didn't change was the one from the distributor to the carb. It looked fine to me though. The one for the PCV valve had new rubber a year ago. There are two rubber caps on the intake but I didn't see any tears in them.

Nothing else to do but take this to a trans shop I guess. Hopefully they can put it on a lift and put it in gear and maybe see if the noise comes when it shifts from 2nd to 1st when slowing down.

 

I took the car to a transmission shop and the owner has experience with hotrods. He drove it with me sitting on the passenger side and he heard the noise when it slows down and also when he shifted it from drive to neutral. He said he's never heard a TH350 trans make a noise like that. I ended up leaving it with him and he's going to put it on a lift and take a further look. Hopefully he can drive it on the lift and at least point to the area the noise is coming from.

Here's a photo I shot today after leaving it...

 

I just remembered , way back I had a t350 in my 55 pu. I ran out of gas about a mile from home and got it towed home. The next time I drove it had a squeak in it. Tranny guy said it was front pump {I think]says it won't hurt it. Next day drove 300 miles to hunt. It quit me in the bottom of a creek bed. This was told to you only to ask if you ever towed or pushed the car? Know anyone with those cameras that go under as you drive?

 

Oh wow thanks for sharing that story. I don't remember hearing that noise when i first got the car. It was never towed or pushed while I've had it. I changed the rooster comb, shifter shaft, filter, and pan. I wonder if maybe a noise is being amplified with those changes. I can't remember when it starting being audible. Weird. At least the transmission shop should hopefully be able to put it on a lift and drive it assuming they are willing to let it warm up enough until the noise comes in.

 

What a headache.. The trans guy drove in it with me but couldn't come up with anything. He put it up on a lift and went through it and didn't see anything and said the differential was a little squeeky. Then he said he could start tearing into things but it would cost money.

I decided to just pick it up after taking 3 buses to get it. It came back really filthy...

In any case the previous owner said he could go on a ride with me and I'm thinking I'll make him stand on the side of the road to see if he can at least pinpoint a general area. Last idea is to drive it for 20 min then take it to a smog place and ask them if I can run it on the dyno and see if the noise can be located that way.

 

Why can't you run it on jack stands ?

 

Thanks for the suggestion when I let it warm up in the garage the fumes get sucked into the apartments since the front entrance is directly next to the garage I park it in. The HOA live in rep
Told me to pull that car outside on the street to let it warm up. I'll ask the previous owners if I can do it at his house since he had a wide driveway. It sucks but I'm always in a jam when it comes to easier solutions. Sorry to be a pain. One day I'll have a 2 car garage and flat driveway.

 

Go find a vacant industrial parking lot someplace.
Jack it up

 

All you need is a floor jack and a couple of jack stands, and a piece of cardboard to lay on.

 

Thanks, the cardboard to lay on from the side when it's on jackstands? I am nervous as hell to get underneath while having my friend put it in drive

 

The cardboard is to keep your clothes from getting dirty. My all means, be safe!!! Maybe you have someone close by to help you out? The drive shaft and rear wheels are spinning as you run it up to speed. If need be, take it to a shop where someone can put it up on a lift and run it in gear to try to recreate the noise and figure out where it's coming from.

 

Thank you. I tried to do just that. The trans shop couldn't put it on a lift when I had it warmed up and making the noise. It takes 20 min of driving for it to appear. All I can do is drive it for a while and put it on jack stands immediately and have a friend put it in drive while I listen from the side but not directly under it. I'll attemp this tomorrow and report back. Thanks

 

How about driving it next to a wall so the sound echos back, maybe you could pin point it that way.

 

Go get a piece of 2 inch pvc pipe, for water pipe plumbing. Cut it about 3 feet long. Put the car on stands, put the tube to your ear and next to different parts of the car so you don't have to climb under. The tube acts like a stethescope.

 

Just as a test, AFTER it starts making the noise, remove your alternator/water pump/AC drive belts, just to see if maybe that's a source. I recently had MY alternator start making some intermittent noise; the rear bearing quieted down after a squirt of oil. Bad alternator bearings, slipping/glazed belts, or any driven accessory can make noise. Use a length of vacuum cleaner hose for your "stethoscope", no need wasting money on pipe you'll never use again.
I am Butch/56sedandelivery.

 

Thanks I tried that as I stick my head out the window but it's tough. I imagine I have to be on the ground listening.

 

Oh perfect I will try that. thank you!

 

Man, when you're beat, you're beat. Just turn up the music.

 

Oh ok thanks. The noise is definitely not intermittent. After 20 min of driving, it does it every single time slowing down. It also does it when switching from drive to neutral. I'll see if I can pinpoint the noise and if it's from the belts I imagine i'd hear it from the front.

 

Haha totally! But sometimes I'm driving by alot of interesting little areas with people staring and waving at me and each time I slow down you hear that stupid noise. It's rather embarrassing.

 

LOL

 

Just honk the horn and wave every time you slow down. <beep beep> Folks will think you're real friendly!

 

Butch, funny thing is I use the plastic tube from my shop vac at 1 shop and a piece of pvc at the other shop. I always have pvc around due to various remodeling projects.

 

Man, that video sure sounds like a u-joint with a few squared off needle bearings. It's not a tough job to put new ones in as mentioned earlier.
Nice Chevy btw!