# 66 gto muncie 4 speed vibration / rattle in shifter "at speed"



## take5 (Aug 9, 2009)

Restoration with Muncie 4 Speed only required fresh gear oil.
The 4 Speed has 121,000 original miles and has not been abused.
The shifter handle vibrates and rattles at 55+ mph in 4th gear.
Is this common? Is there a "fix"? Muncie shifts very smooth in all 4 gears.
Do external shifter linkage parts wear and overall tolerances change?
Has anyone experienced or are you currently experiencing this vibration / rattle in your shifter handle.


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## Eric Animal (Oct 28, 2007)

Had a couple that did vibrate like yours.....tryMedatronics Corporation's 5 Speed Home page! Ask for Paul and tell him Eric from long Island sent ya"......


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## freethinker (Nov 14, 2009)

take5 said:


> Restoration with Muncie 4 Speed only required fresh gear oil.
> The 4 Speed has 121,000 original miles and has not been abused.
> The shifter handle vibrates and rattles at 55+ mph in 4th gear.
> Is this common? Is there a "fix"? Muncie shifts very smooth in all 4 gears.
> ...


start with checking ujoints then check tailshaft output bushing.


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## geeteeohguy (Feb 2, 2008)

I've had a few that vibrated over the years. Biggest culprit always seemed to be U joint or driveshaft issues. Sometimes tire balance and trueness, also. Sometimes it's a worn out pilot bushing, when a bearing was not used (as it should have been!) The '67 shifter is a softer shifter than the '64--'66 units...it is rubber bushed to prevent just this. Sometimes the grommets wear where the shift rods connect to the shifter. I use the metal grommets, but they sell nylon ones for quietness and smoothness. Hurst sells a bushing and spring clip set for very little $$$ that will tighten up the rods. Also, your shifter IS 43 years old...it could need an overhaul/freshen up. Good luck.


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## Jerry64 (Apr 20, 2010)

Most of the shifter vibrations I have ran across are from worn internal parts transmitting through the shifter rods into the shifter.Most times it was from the syncro stack of 3rd and 4th gears..........JB.


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## take5 (Aug 9, 2009)

Thanks for everyone's response and input.
I'll be following through with getting it as "right as possible".
To date because calling Medatronics was first suggested Paul stated it was a
"Harmonics Issue". He said the flywheel may need to be balanced and to check the drivetrain for overall straightness, etc.
I will start with ujoints, bushings, replacement parts for shifter and kits suggested.
When the Muncie was inspected I was told there were no issues or any new internal parts needed. Muncie was cleaned & new 85 -90 W gear oil added.
Original flywheel was kept and machined as little as possible with all new clutch components.
I will be checking again with the mechanic on these items.


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## freethinker (Nov 14, 2009)

take5 said:


> Thanks for everyone's response and input.
> I'll be following through with getting it as "right as possible".
> To date because calling Medatronics was first suggested Paul stated it was a
> "Harmonics Issue". He said the flywheel may need to be balanced and to check the drivetrain for overall straightness, etc.
> ...


its not a flywheel balance issue. that would show up reving the engine with car stopped and trans out of gear. it is probably something from the input shaft back.


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## Rukee (Feb 8, 2007)

I had the same issue, turned out the car had the wrong shifter boot under the console. Replaced it with the right one and it stopped.


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## Jerry64 (Apr 20, 2010)

Ifyou have to go internal,Check the clutch dogs under the shifter rings.......JB.


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## 68GTO4004Spd (Jun 19, 2008)

Mine does that, I just keep my hand on the shifter. Easy fix


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## Oldsmobileman (Dec 8, 2008)

You mean my Goat isn't supposed to do that? hahaha. Replaced shocks, uv joints, rear end bearings, new fluids, new speedometer gear and cable, etc, etc. Still couldn't solve the shimmy and shake. Clutch went out the other day, disected it. Tranny had a whopping 3 bolts in the pressure plate, 3 in the bellhousing, and no pilot bushing! Needless to say the bolts that were in the bellhousing belonged in the flywheel, and vice versa...no wonder they wiggled out. Car has always vibrated really bad at 55. Vibrated so bad where the clutch pedal screws in was almost completely vibrated out and holding on by one thread! New clutch, new shifter (refurbished vintage 67 of course), new..wait a pilot bushing period, throw out bearing, new oil, full service! Now she doesnt vibrate like hell till 65! 3500 rpms!!!!

ps we had purchased 3 different clutch kits before we got the correct one with all of the right parts (most important pilot bushing), guessing from the other 2 packages the last owner did the "whatevers in the box is what goes in" routine, and that's why there was no pilot bushing!! sorry to ramble.. Howard


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## ALKYGTO (Mar 29, 2010)

I hope you used some loctite on those bolts.


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