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Topic: Help! Lost gears on a M/T.

in Forum: C3 Driveline Components


Help! Lost gears on a M/T.

Posted: 2/7/07 11:03am Message 1 of 5
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Leavenworth, KS - USA
Joined: 1/24/2007
Posts: 426
Vette(s): MM Red 1971 T-top,LS5,4-speed, black leather C5 seats, Hooker sidepipes. Previous: 64 Coupe, 65 Roadster L76 / N14
My first posting on this forum. Who knows, maybe someone else has experienced this "opportunity to work on the vette." 
 
Within a couple of weeks of purchase, I lost 1st and 2nd gears, and now it won't shift into reverse either (can't remove the key). Cry I have a '71 4-speed M/T hooked up to a 454.  Don't know yet which flavor of tranny.
 
I got her up on jackstands, in the garage (boy, is it cold down here right now!!), and found that most of the nuts on the shift rods were loose, not even hand tight.  Also, the clutch cross shaft had tons of slack.  I'm hoping it is just a linkage adjustment issue combined with the sloppy cross shaft.
 
I got the parts to refresh the cross shaft (studs, seals, etc.). I also read that it requires a special gap tool to adjust the linkage properly.  If I can get the linkage close, hopefully a "real" mechanic can fine tune the rest.
 
Meanwhile, I'm praying there is no problem with the guts of the tranny.
 
Does it sound like the linkage? Any thoughts?  I appreciate your feedback.
 
Sign me "Mike, freezin' my butt off in the Land of Ahs" (did I say it was cold down here?)
 
PS This is Vette No 3.  I restored a '64 and '65 previously.



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Help! Lost gears on a M/T.

Posted: 2/7/07 12:52pm Message 2 of 5
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Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
If there is a lot of slop in the linkage like loose nuts, then it won't go into gear. What happens is the arms on the shifter won't be in the correct position and prevent you from moving through the gates. It can also cause the transmission arms not to drop into their detent position and cause binding. So unpin the linkage at the transmission arms and make sure all three arms are in their neutral postion. The two forward arms (1st & 2nd, 3rd & 4th) have 3 postions with center being neutral. I can't remember what direction is neutral on the reverse arm. I would look but am at work at the moment. Once all are in neutral move each arm through their position and return to neutral before going to the next. It can help to disconnet the driveshaft so you can rotate the output shaft to make sure it does go into gear. If all this checks ok then you can make an alignment tool out of sheet metal for the shifter. I think the dimension for it is in one of my books so I can't give you the info right now. maybe one of the other members can help with that. With the tool inserted reattach the bars to the trans and adjust the linkage. One thing, there is not much room to get the tool into position. Hope this helpsThumbs%20Up


Help! Lost gears on a M/T.

Posted: 2/7/07 8:49pm Message 3 of 5
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Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
The tool for setting up the linkage is pretty simple to make. Get a piece of steel that is about .040" thick by 1" wide and 4" long. Trim one end .so it is .644" wide and extends back 1". Put a .05 x 45deg chamfer on the corners of the .644" tab to help with sliding it in to the shifter from under the vette. Now measure back about 1.75" from the end of the tab and bend down 35 deg so it will clear the floor pan. If you have the Corvette shop manual there is a drawing of it on page 8-2 suncountry2007-02-07 20:49:42


Help! Lost gears on a M/T.

Posted: 2/8/07 9:00am Message 4 of 5
Former Member
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Leavenworth, KS - USA
Joined: 1/24/2007
Posts: 426
Vette(s): MM Red 1971 T-top,LS5,4-speed, black leather C5 seats, Hooker sidepipes. Previous: 64 Coupe, 65 Roadster L76 / N14
Thanks for the quick reply Glen!  I echo the other comments I read about this site today!  You always get help when you need it here. Tongue Vette drivers are the BEST!
 
I'll give your instructions a try, even the fabrication of the gage.  Guess I ought to break down and get a workshop manual, eh?
 
Now why didn't GM make and sell this special tool / gage?  I'm sure this problem occurs once in awhile as long as you have nuts that will vibrate free.  I'm thinking of adding lock washers when I adjust the linkage to prevent this from happening again.  Whaddayathink?  Is this necessary?  Maybe Loctite too?
 
Thanks again!  Mike



Help! Lost gears on a M/T.

Posted: 2/8/07 1:19pm Message 5 of 5
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Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
I don't have lock washers on mine and have not had any issues but it can't hurt. I think some of the Corvette parts supply places may sell the tool. I just used a 1" wide puddy knive and took a Dremel tool to it. It wasn't perfect but got me close enough. Right now I'm in the middle of replacing my A/C hoses and VIR valve. This winter is the A/C system. I want to be coolWink on my drive to Carson City this June.


in Forum: C3 Driveline Components


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