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Topic: Automatic Transmission issue on my '85.

Automatic Transmission issue on my '85. (1/7)
 3/26/20 1:11pm
RetiredNavyChief
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Phenix City, AL - USA

Vette(s):
1985 Chevrolet Corvette VIN: 1G1YY0789F5107057 photographs to follow.


Joined: 2/9/2020
Posts: 10

Hi all, I know I'm making a lot of posts, I hope you don't mind.  This is the first Corvette I've ever owned, and it's a project to say the least!  I've been sorting through all the disconnected/rotten/blocked-off vacuum/emissions lines and I've got the motor running smoothly enough to drive around a bit. 

However...

I have encountered the following condition with my(presumably original) automatic transmission:

 

Park:  works

Reverse:  works

Neutral:  works

1, 2, D, OD:  only first gear works.  I have been researching, and I believe I should have a 700R4 transmission.  I think it's also known as a 4L60?  I've also read that my transmission's condition is quite possibly a result of a defective Governer.  Would anyone like to weigh-in?  Most of my experience is old Euro manual transmissions(well, there is that ElectroMagnetic 4-speed Renault Dauphine hiding in my Dad's garage), and '70s Dodge 727s.  Any guidance prior to handing this over to a transmission shop would be most appreciated!

 

Rick



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Re: Automatic Transmission issue on my '85. (2/7)
 3/27/20 8:27am
Atchafalaya
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Atchafalaya Basin, LA - USA

Vette(s):
Black 1979 L-82 Black 1996 LT1 Black 1999 Coupe


Joined: 3/20/2009
Posts: 554

Your shifting problems may very well be related to the vacuum lines be disconnected/blocked off.

Re: Automatic Transmission issue on my '85. (3/7)
 3/27/20 12:55pm
RetiredNavyChief
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Phenix City, AL - USA

Vette(s):
1985 Chevrolet Corvette VIN: 1G1YY0789F5107057 photographs to follow.


Joined: 2/9/2020
Posts: 10

Thanks for your answer.  I was under the impression that the '85 vette used the cable from the throttle-body to the transmission along with the governer but that it didn't have any vacuum lines?

 

Rick



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USN 1982-2007. 

Re: Automatic Transmission issue on my '85. (4/7)
 3/27/20 1:03pm
Atchafalaya
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Atchafalaya Basin, LA - USA

Vette(s):
Black 1979 L-82 Black 1996 LT1 Black 1999 Coupe


Joined: 3/20/2009
Posts: 554

RetiredNavyChief said:

Thanks for your answer.  I was under the impression that the '85 vette used the cable from the throttle-body to the transmission along with the governer but that it didn't have any vacuum lines?

 

Rick




 

I don't really know Rick.

What I  do know it's always a shot in the dark exactly what parts are on a vehicle Bubba used to own.

Re: Automatic Transmission issue on my '85. (5/7)
 3/27/20 8:53pm
Adams' Apple
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Duncanville, TX - USA

Vette(s):
1985 Coupe-L98/Auto,Bright Red/Carmine. 1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.


Joined: 3/18/2009
Posts: 2144

Your no shift issue could very well be a broken, or damaged governor gear. It could also be the TV(throttle valve) cable from the throttle body to the trans could be binding, or completely out of adjustment. Check to see that the inner cable will pull out, and go back in with ease by disconnecting the plastic clip from the throttle linkage on the throttle body. The inner cable should have a spring loaded feel to it as you pull on the cable.

If the cable appears to be ok, then your next place to go would be a look at the governor, and it's drive gear. Getting the cover off the trans is easy enough, but removing the governor itself can be a little frustrating on these cars....it's a tight fit. The governor is located on the driver side rear of the trans, under a large, round, stamped sheet metal cover. A screwdriver and hammer will get the cover popped of(have a drainpan under the area...you will loose a small amount of fluid). With the cover off, reach up and see if the governor spins freely in the trans. If it does, the gear is broken, and you will need to remove the governor and replace the gear. If the gear is still meshed with the teeth on the trans output shaft, but you can turn it with a little force, the gear is "apple-cored", and will need to be replaced. If the gear is in good condition, then your next likely culprit will be a stuck TV valve in the valve body, which is internal on the trans. Checking/fixing this would best be left to a trans specialist.



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Re: Automatic Transmission issue on my '85. (6/7)
 4/5/20 9:13pm
RetiredNavyChief
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Phenix City, AL - USA

Vette(s):
1985 Chevrolet Corvette VIN: 1G1YY0789F5107057 photographs to follow.


Joined: 2/9/2020
Posts: 10

Adams' Apple said:

"Your no shift issue could very well be a broken, or damaged governor gear."

 

I picked up a Governor on EBay for about $40.  Today I jacked the Corvette up, got the G-Cover off without destroying it OR it's seal, and pulled the Governor out.  The bottom 2/3 of the gear was gone!

So after fishing out the bits I slapped the 'new' one in, jammed the cover back on, and proceeded to slush-box my way through all the gears!  Thank you to everyone who weighed in on this issue.  Now I can concentrate on the damned idle...vacuum...emissions...exhaust...issues.





|UPDATED|4/5/2020 6:13:56 PM (AZT)|/UPDATED|


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USN 1982-2007. 

Re: Automatic Transmission issue on my '85. (7/7)
 4/5/20 9:15pm
Adams' Apple
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Duncanville, TX - USA

Vette(s):
1985 Coupe-L98/Auto,Bright Red/Carmine. 1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.


Joined: 3/18/2009
Posts: 2144

Good to hear!  👍



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Joel Adams  
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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