My '65 (L76 with M20 close-ratio) has a disturbing tendency to pop out of 3rd gear (into neutral) when I am in 3rd gear on a high rpm (3000 or so) decelleration for more than a few seconds. The times I noticed this was when I was going down a very steep hill or exiting a freeway and decellerating. It does not happen when accellerating in 3rd. This is obviously a transmission issue, but what specifically causes this and what is the fix? The transmission has only 47K original miles on it and I doubt that it has ever been out of the car. -Clark
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Re: Pops out of 3rd gear
clark,
Had the exact same issue on my car some years ago. The easy and inexpensive thing it could be is a shifter out of adjustment. The most likely culprit is worn or damaged synchros in the transmission.
jd -
Re: Pops out of 3rd gear
I thought that the synchros only come into play DURING a downshift. The issue I have is when it is already in gear, not going into gear. So, does the 3rd gear synchro hold it into gear during decelleration? It downshifts into all gears very smoothly. Well, that is except for 1st gear on a cold day until the trans warms up.
I just read in a tech manual that the engine will have to be removed from the car to take the trans out for service. Yikes, that sounds like it would be expensive, labor-wise!
-ClarkComment
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1963 Corvette Conv. 327/360 NCRS Top Flight
2006 Corvette Conv. Velocity Yellow NCRS Top Flight
1956 Chevy Sedan. 350/4 Speed Hot RodComment
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Re: Pops out of 3rd gear
My 68 Muncie equipped original owner has about 95K on it, transmission shifts great and stays in all gears. How do you know your 4-speed only has 47K on it?
One thing not to do is hold your hand on the shifter after selecting a gear, going down the interstate holding it in 4th gear is easy to do, but not recommended.Comment
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Re: Pops out of 3rd gear
Clark, I think it's a misadjustment of the linkage, you're not fully in 3rd. Try adjusting the 3-4 linkage, that may be all you need. And, no, the engine does not have to come out. Bill.Comment
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Re: Pops out of 3rd gear
I agree with Bill. My '65 327 / 365 started jumping out of third with a bang and the shift lever kicked back. It turned out to be a loose bolt on the side cover linkage, giving it less travel. I tightened her up and checked for proper travel and viola' all was well.
Try the easy stuff first, my motto. Good Luck. KenComment
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Re: Pops out of 3rd gear
Clark:
If the shifter is not out of adjustment you probably have a bad slider, its the part the synchro travels in. It is groved or you could say gears radially around the outside. They should be straight, but as used they widen and allow the gears to disengage or poping out of gear. Fix remove transmission from car and replace slider. You can do it in a day withour much trouble.
WesComment
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Re: Pops out of 3rd gear
Jim,
I am curious, why is holding onto the shifter when it is in gear not a good thing?
I am guilty of this practice
KurtComment
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Re: Pops out of 3rd gear
Holding the shifter puts pressure on the internals and wears them out quickerFounder - Carolinas Chapter NCRSComment
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Re: Pops out of 3rd gear
Clark,
Adjust your shifter linkage as per the 65 Corvette Shop Manual. Can be purchased from the NCRS office in Cincy.
If that doesn't help, remove the trans and take it to a shop that specializes in transmission rebuild.
There is absolutely no way it can be diagnosed over the internet. Only confusion with no magic bullet.
Get ready to spend some bucks.
JRComment
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Re: Pops out of 3rd gear
I've been building 4spds for 40+yrs (mostly Muncies), and there are several factors that could be contributing to the problem of jumping out of gear.
First, and easiest of course, is improper adjustment of the shifter. If something is loose or improperly adjusted in the shifter linkage, then correcting that will be the easiest, cheapest fix and you'll avoid pulling and going into the tranny.
If the tranny has been subjected to lots of previous abuse and power shifts, which I still do all the time, this will cause excessive wear between the engagement teeth of the gear, wear in the splines of the syncro slider and excess wear of the brass synchro rings which will contribute to reduced synchronizer function, thus, more wear.
The input shaft of all trannys has a pilot on the end which is centered with the rear of the crankshaft by a pilot bushing (pilot bearing on later cars) installed in the rear of the crank. If the hole in the pilot bushing has become enlarged (due to age, mileage, abuse, etc), then this allowes the input shaft to wobble and can contribute to "kicking" the tranny out of gear during deceleration, particularly 3rd gear.
If, after adjusting your shifter linkage, it still jumps out of 3rd gear during deceleration, then the ONLY fix will involve removal of the tranny.
To check the hole in the pilot bushing, you MUST remove the bell housing and clutch to gain access to the bushing. I use an old input shaft inserted into the bushing and wiggle it up and down. THERE SHOULD BE VERY LITTLE UP-DOWN MOVEMENT. If you don't feel comfortable doing this kind of a check, then buy a new pilot bushing (they are CHEAP), slip it onto the pilot if the tranny input, wiggle it, then compare the amount of wiggle in the installed bushing, or, just measure the difference in hole size between the installed and new bushing.
If the installed bushing has minimal, or no detectable wear, then the next step is to disassemble the tranny. If you're going to do this, you would be miles ahead to buy a rebuild kit, AND, a pair of Tork Loc syncro sliders. The Tork Loc sliders have an additional back cut in each end of the splines SPECIFICALLY to help keep the tranny in its selected gear. These are a GREAT fix for a tranny that ocassionally pops out of gear. If it is routinely popping out of gear, under any condition, then a new gear AND syncro slider is the only fix.
BE VERY CAREFUL ABOUT YOUR CHOICE OF A "TRANNY REBUILDER"!!!!
Just because a shop rebuilds trannys, DOES NOT mean they are proficient at specifically rebuilding and repairing Muncies. You need to locate someone that has lots and lots of experience with Muncies so that you get a quality rebuild.
One of the MOST COMMON PROBLEMS with a Muncie is oil leaking around the hole for the counter shaft at the front of the main case. VERY few rebuilders can PROPERLY, and permanently fix this problem.Comment
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Re: Pops out of 3rd gear
The seller, Pro Team, advertised this car (#10,118) as having 46K ACTUAL MILES and appeared to be THE REAL DEAL (their words in caps). In actuality, I have no way of knowing, really, if the mileage is correct as advertised. I just trust the Pro Team owner, Mr. Michaelis.
I will go with the mileage on the odo until proven otherwise. -Clark
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Re: Pops out of 3rd gear
Kurt -
Leaving your hand on the shift lever will accelerate wear on the ends of the shift forks where they engage in the grooves in the sliders, and will wear those grooves as well. The detent/interlock mechanism inside the side cover positions the forks where they belong so the ends of the forks "float" in the slider grooves; resting your hand on the lever can cause one side of the fork to be pressed against the side of the groove in the slider.
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Re: Pops out of 3rd gear
Clark:
I love working on my car as much as driving it. I wouldn't spend big bucks letting someone else rebuild something when I can do it myself. I have let some experts work on somethings I thought I couldn't handle and they screwed it up beyond recognition and I ended up doing it myself or relying on a very trusted soul.
WesComment
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