Help identifying a transmission noise in a 1965 Muncie M20 CR.
I have a 65 365HP convertible with a close ration Muncie. When I bought the car it had an odd squeal shifting into second. There was no shifting difficulty nor any noise or vibration once in gear on acceleration or deceleration, nor any other symptoms. I had the engine out for a rebuild so I decided to rebuild the Muncie. All parts that are replaced as a standard rebuild were replaced (i.e. syncros, bearings, clutch hubs, shift forks etc.). I also spoke to two expert rebuilders and sent them photos of my gears to get advice on servicability. When finished, the transmission worked fine but still had the squeal going from 1 to 2 (though not as loud). It has since developed an intermittent squeal idling with the clutch in. I replaced the pilot bearing, TO bearing, clutch and pressure plate at the same time as the rebuild. Nearing wits end, any ideas?
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Re: Help identifying a transmission noise in a 1965 Muncie M20 CR.
Jeff - Just so I understand, when you say 'Pilot Bearing' do you actually mean 'bearing' as in something with rollers or do you just mean Pilot Bushing, like GM used? The reason I ask is, back nearly 30 years ago, I saw some mention of folks using a Roller Bearing in place of a Bushing and thought that's a great idea. About 6K miles later, I was out at the local DragStrip for the Wednesday Night Drags and had the Trans in first gear
and just casually let the clutch out, as I was moving up for tech inspection. Oddly, the trans kicked out of first gear. No real pressure on the gas pedal, just lightly letting out the clutch pedal to let the car move forward in line. Shortly afterwards, I talked to a friend who owned a Transmision Shop and his first comment was...that sounds like a possible problem with the input shaft bearing/bushing. Pulled the trans and found my new and improved roller bearing, GM version by the way, with 17 rollers versus the 12 from a Mr Gasket version, has disintegrated.
This was a long time ago and I almost always double check to see the concentricity of the bellhousing and recall it was close to the specs but was kinda stunned that the bearing had given up so quickly. Replaced it with the GM bushing and all has been right ever since. Not saying a true roller bearing is the culprit in your situation but I'm leery of roller bearings. Pics shows the disintegrated bearing alongside a new GM roller bearing.
Regarding the sound/squeal that you heard, there was no odd sound from my setup, just the popping out of gear...and only when in first gear.
Moose 6K Mile Old Roller Input Brg.jpgMike T. - Prescott AZ. -
Re: Help identifying a transmission noise in a 1965 Muncie M20 CR.
Mike, Yes, I meant bearing. I too used bushings only until this rebuild of the trans and clutch replacement. I had been told that the roller bearing units were superior in maintaining tight tolerances and heat resistance. Currently I have a GM unit in there, but I agree that is a definite suspect for the noise at idle with the clutch in. However, I am still baffled by the shift squeal. Thanks for your input there, I will try a bushing this time for problem #2. Still would appreciate any thoughts on the shift noise.Comment
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