Transmission stuck in reverse

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Aug 20, 2013 | 12:15 PM

jhinkle

Thread Starter

Heel & Toe

Joined: Jun 2012

Posts: 21

Likes: 0

From: Annapolis MD

Transmission stuck in reverse

Looking for some help! I own a 1969 corvette with a 4 speed M21 transmission - original to the car. The transmission is stuck in reverse, no matter what gear the car is in. This is also the case when in neutral. I looked at the reverse linkage, nothing appears to binding the linkage from moving freely. I tried to move the linkage by hand back and forth but could not dislodge it. Any recommendations as to what the issue is and how to resolve would be greatly appreciated. Thanks

Aug 20, 2013 | 01:10 PM

restoman1

Burning Brakes

Joined: Dec 2010

Posts: 848

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From: CA

Stock shifter or aftermarket?

Ed

Aug 20, 2013 | 01:13 PM

jhinkle

Thread Starter

Heel & Toe

Joined: Jun 2012

Posts: 21

Likes: 0

From: Annapolis MD

Stock shifter as well.

Thanks Ed

Aug 20, 2013 | 02:19 PM

lars

Tech Contributor

Joined: Aug 1999

Posts: 14,380

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From: At my Bar drinking and wrenching in Lafayette Colorado

Remove the 3 shift levers from the tranny, use a heavy Crescent Wrench on the shift arm shafts to move them all into neutral, re-attach the shift levers, and then correctly adjust your shifter.

Aug 20, 2013 | 04:36 PM

A88FXRS

Racer

Joined: Dec 2007

Posts: 374

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From: PHILADELPHIA PA

possible the internal shift fork broke, leaving box in rev. see this thru side cover.

Aug 20, 2013 | 04:50 PM

jhinkle

Thread Starter

Heel & Toe

Joined: Jun 2012

Posts: 21

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From: Annapolis MD

Lars,

Should I use vice grips to rotate the shift arms shafts? Is it clockwise to rotate out of gear? thanks

Aug 21, 2013 | 01:12 PM

lars

Tech Contributor

Joined: Aug 1999

Posts: 14,380

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From: At my Bar drinking and wrenching in Lafayette Colorado

No, you use a heavy Crescent wrench, as noted in my post above. Vice Grips will leave nasty impression marks on the shafts. Which way to rotate depends on which gear it's stuck in. Rotate each arm back and forth intil it moves one way or the other and then verify that you can get the 1-2 and the 3-4 levers into all 3 positions. Then, put them both in the center (neutral) position. Rock the reverse lever back and forth until it moves into it's 2nd position and can be easily moved back and forth. Neutral is easy enough to determine when the driveshaft can be rotated freely. Then, do a precise adjustment and setup of the shift linkage - the cause of your situation is improperly adjusted linkage.

Lars