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1967 Chevelle
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Discussion Starter · #1 ·
I've been researching this for the past few days, but am still not 100% sure if my issue is with the pilot bushing or the throw out bearing. When the car is in Neutral, 1st, 2nd, or 3rd gear the is a horrible noise coming from the transmission. It sounds like a grinding, but only occurs when the clutch pedal is out. As soon as I depress the pedal, it stops. It also seems quiet in 4th gear.

Car is a 1967 with a 327 and a 4 speed (the previous owner converted it from an automatic). Is the issue with the pilot bushing out throw out bearing?

Just a little background...When I bought the car, it was in primer and had no glass, weatherstripping, or even exhaust on the car, so wasn't able to really get it on the road. I recently got it back from the shop (they did bodywork and paint, installed the glass, trim and exhaust), so haven't put many miles on it and am now finding these that I was previously unaware of. Any help is appreciated!
 

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I'd put my money on throw out bearing being bad. But you have to pull the trans regardless so I'd swap both since they're cheap anyway. depending on clutch condition it might not be a bad idea to swap that as well since a clutch kit usually comes with both throw out and pilot.
 

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1967 Chevelle
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Discussion Starter · #4 ·
I originally thought it was the throw out bearing, but the more I read, it sounded like if its occurring with the pedal out, the its the pilot bushing, which is why I'm confused. I've never removed a 4 speed before, so any advice on doing so? Also, if I decide to replace the clutch, any suggestions on brand? This will be a street cruiser and don't plan on any track time (as least not any time soon). Thanks
 

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Sounds to me like it's something inside the transmission. When the transmission is in 4th gear it's a direct link from the input shaft to the output shaft, which bypasses all of the gears. If the transmission makes noise in all gears except 4th and when you push in the clutch then it's probably something in the gears.
 

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It's only occurring when the clutch pedal is out. Once I push on the pedal, regardless if in neutral or in gear, the noise goes away
When the engine is running, the input shaft is rotating whenever the clutch pedal is 'out'. The output shaft only rotates if you are in a gear (1,2, 3...). In neutral, there is no rotation of the output shaft because there is no 'connection' to the rotating input shaft.

From your description, your 'noise' is related to the rotating input shaft. Could be the throw out bearing, the pilot bushing, or the input shaft bearing. Or, something easier like a lack of lubrication (low oil).

Because you intend to replace the clutch, plan on replacing the throw out bearing and the pilot bushing too. When apart, check the input shaft bearing.

Match the throw out bearing to the pressure plate configuration of the clutch.

Here's a link to a visual:


The RAM 'Muscle car' line sold by Summit is a good everyday clutch for your 327 (it's just a small 'step above' OEM).

Pete
 

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1967 Chevelle
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Discussion Starter · #11 ·
Thanks for the info. I actually wasn't planning on doing the clutch, but if that's something that I should do in conjunction with the pilot bushing/throw out bearing, then I'll look into it.

One thing I forgot to mention in my original post is that its difficult to get it into reverse. It takes a lot of pressure to push it over to the left before going into gear. Not sure if that is related or not.
 

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I have a Muncie 4 spd and one time this happened lol I had to find the part online from a trans shop lol if the clutch was out it would actually not make any noise I guess everyone s experience would be diff here but oh man I put the clutch in and Haa it’s sound like a stampede of metal as it spun freely 4 sod’s are pretty light u and a buddy can get it out and in a few hours in my case had to wait for this in the mail a little while hope u find your problem. When in doubt pull it out 😂
704755
 

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its not the pilot bushing because the noise stops when the pedal is out - which is when the input shaft is rotating with the pilot bushing
its not the throwout bearing because when you depress the pedal the noise stops - which is when the bearing has THE most force against it

I agree with big gear head that is internal to your transmission. Pull it out to have it looked at and while you are doing that; change the clutch disc, pp, throwout bearing, and pilot bushing.
 

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Thanks for the info. I actually wasn't planning on doing the clutch, but if that's something that I should do in conjunction with the pilot bushing/throw out bearing, then I'll look into it.

One thing I forgot to mention in my original post is that its difficult to get it into reverse. It takes a lot of pressure to push it over to the left before going into gear. Not sure if that is related or not.
I mis read something you said. It is not mandatory that the clutch be replaced; only if necessary (and perhaps only the disc). I recommend replacing anything that is 'questionable'. It's 'parts only' once it's apart. BUT you do need to 'match' the pressure plate and the throw out bearing.

Not that it relates to your 'noise', but do you have the Muncie 4 speed? The Saginaw? Borg Warner? All can 'fit'. It's good to know. I've attache a doc that should help you with the ID.

Here's a link to some useful Muncie info:


They very first thing I would do (before pulling the transmission) is change the transmission oil. Or at least, check to see if it's low. It should be just below the level of the fill plug (on a Muncie; I'd have to look up the Saginaw and BW). I'm not saying that is your problem, but it's cheap to check. It takes about a quart to fill.

The 'reverse' shifting issue can be simply greasing the shifter, and/or some binding in the linkage.

Pete
 

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Exactly what raiderss said, when the clutch pedal is out the input shaft and crank are turning together, so that eliminates the pilot bushing. If it was the throw out bearing then it would only make noise when you push in on the pedal and it would not matter if it was in 4th gear or any other gear. He said that it doesn't make the noise in 4th gear, which is a direct connection between the input and output shaft. The noise is coming from inside the transmission.
 

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I've never removed a 4 speed before, so any advice on doing so? Thanks
1) Get the car up on a hoist or up on jack stands as high as you can get it.
2) Drain the transmission oil.
3) Remove the driveshaft
4) Unbolt the shifter and linkage and remove.
5) Unhook the speedo cable.
6) Remove the transmission mount bolts, raise the back of the tranny and remove the transmission crossmember.
7) Let the tranny back down.
8) Remove the four bolts that hold the tranny to the bell housing, and pull the tranny out. If it hangs up on the clutch, have somebody push on the pedal a little bit while you pull on the tranny.
9) Don't drop the tranny on the ground or on YOU. Get help if you need it.
10) If you are going to inspect the pilot bearing and clutch, go on to step 11.
11) Disconnect the clutch linkage so it no longer pushes on the fork.
12) Remove the the bell housing to engine block bolts and remove bell housing.
13) Remove the pressure plate bolts and remove pressure plate and clutch.
14) Inspect the flywheel and pilot bearing. I would STRONGLY recommend replace the pilot bearing and having the flywheel resurfaced. Make sure to have it mic'd to be sure it hasn't been resurfaced too many times, and inspect the starter ring gear for any bad teeth.
15) Install pilot bearing then install flywheel and torque to specs.
16) Lay the clutch disc on the pressure plate, making sure the disc is facing the CORRECT way.
17) Carefully put the disc and pressure plate up on the flywheel and reinstall the pressure plate bolts, but leave them loose.
18) Use you clutch alignment tool (if you don't have one, GET one, many new clutches come with one) insert alignment tool into the pilot bearing and center the tool (and the clutch disc) in the pressure plate opening.
19) Once you are satisfied the clutch is aligned properly, tighten the pressure plate bolts. The alignment tool should EASILY slide in and out without binding or dragging. If not, repeat step 18 until it does.
20) Reinstall the bellhousing with the fork and the throwout bearing in place.
21) Here is where I like to 4 get 3" bolts the same diameter and thread as the 4 transmission mounting bolts, cut off the heads and cut a slot in the cut off end. I then screw those into the bellhousing to use as guides.
22) Place the tranny up on the guides, make sure the input shaft slides through the throwout bearing and slide the tranny into place. Sometimes it helps to shift the tranny into a gear and rotate it slightly to get the pnput shaft splines to line up with the clutch disc. You can also bar the engine over a little. Make sure the trany slides ALL THE WAY in smoothly. Don't force it. If it doesn't go, figure out WHY, and fix the problem. Once the tranny is all the way in, unscrew the guides with a straight blade screwdriver one at a time and insert the bolts. After that, just do everything in reverse order of taking it apart. When you go to hook up the shifter, make sure the tranny is in neutral by spinning the driveshaft by hand and hook up you shifter linkage. I don't know the procedure for the stock shifters, but on a Hurst, you insert the shifter centering tool (or a drill bit the same diameter) through the shifter body, and hook up your linkage, making sure nothing binds.




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