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12/14/10 11:18pm - Original Message: 'How to remove transmission speedometer gear fitting'
leggomymako
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East Hampton, CT - USA

Vette(s):
1975 Corvette with T-Tops

Joined: 10/20/2010
Posts: 27
I am having a bear of a time trying to remove the fitting that holds the plastic gear for the speedometer cable in the transmission.  I have already removed the retainer.  I have tried unscrewing this thing, and prying it out, but no luck. 

Does anyone have any insight on how to get this thing out?
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12/15/10 7:59am - Reply: 'How to remove transmission speedometer gear fitting'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
Are you talking about the plastic housing that fits in the trans?
They can sometimes be a pain. Spray around the outer perimeter with WD40(or whatever) first. Tap IN on it gently with a small hammer/plastic/rubber mallet. Then use a large pair of pliers, or channel locks to twist it as you pull out on it. You may need to push it in/out a little as you go. They usually don't like to be pulled out crooked, so keeping it straight in the hole will help. That's why you need to tap it in first, to get it straght.
hth
Adams' Apple2010-12-15 06:00:44

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Joel Adams
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12/15/10 9:45pm - Reply: 'How to remove transmission speedometer gear fitting'
leggomymako
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East Hampton, CT - USA

Vette(s):
1975 Corvette with T-Tops

Joined: 10/20/2010
Posts: 27
[QUOTE=Adams' Apple] Are you talking about the plastic housing that fits in the trans?
They can sometimes be a pain. Spray around the outer perimeter with WD40(or whatever) first. Tap IN on it gently with a small hammer/plastic/rubber mallet. Then use a large pair of pliers, or channel locks to twist it as you pull out on it. You may need to push it in/out a little as you go. They usually don't like to be pulled out crooked, so keeping it straight in the hole will help. That's why you need to tap it in first, to get it straght.
hth
[/QUOTE]

Wow!  Thanks for the tip, it popped right out.  Unfortunately the gear was perfect.  I cleaned everything up, put it back together, and I took it out for a spin.  The speedometer jumped between 0 and 10 at first, stayed at 10, then I went over a bump and the gauge is dead again.  I think I may need to have it rebuilt.  I hooked it up to my drill last night and it was making some grinding noises, but it worked up to 100 miles per hour. 


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Spending more time under the 'vette than in it since October 2010
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12/15/10 10:50pm - Reply: 'How to remove transmission speedometer gear fitting'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
Did you look at the gear inside the trans? If the speedo is bouncing, it's possible the gear on the shaft is loose, or otherwise damaged. If the little clip is gone/damaged, it can cause the speedo to bounce around like that, and maybe work one time, and not the next.
If the speedo head itself(dash gauge) is making noise, you need to determine if it is in fact a noise IN the head, or the cable making noise....


btw...I'm assuming this is an automatic trans?
Adams' Apple2010-12-15 20:53:08

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Joel Adams
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12/16/10 9:00am - Reply: 'How to remove transmission speedometer gear fitting'
leggomymako
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East Hampton, CT - USA

Vette(s):
1975 Corvette with T-Tops

Joined: 10/20/2010
Posts: 27
I didn't really pay too much attention to the gear inside the transmission, but the section that I did see looked ok.  I did not check to see if it was loose.  If it is loose, is there anything I can do about it without having to take the transmission apart?

Where is this little clip that you mentioned? 

The cable should be ok, it is a brand new cable.  I should mention that there is a 90 degree elbow between the cable and gear.  I tested it out while I had everything apart, and it turns easy. 

Also, it is the original 4 speed manual transmission.



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Spending more time under the 'vette than in it since October 2010
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12/16/10 1:04pm - Reply: 'How to remove transmission speedometer gear fitting'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
Ah HA!
The 4 speeds had a 90deg adapter that is actually a reducer. There is a gear set inside there that can cause problems, also. If the speedo works spinning it with a drill, but doesn't with it connected to the trans, and the trans gears are ok, then that leaves the reducer/adapter as the culprit.

Being a 4 speed, it's gonna be dang near impossible to look up in there and see the drive gear...unless you have really tiny eyeballs...or a borescope. The four speeds do NOT use a clip to hold the drive gear...it is pressed onto the shaft. They do get loose, tho it is rare for that to happen. My bet is on either the adapter/reducer, or the speedo head itself, at this point.


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Joel Adams
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             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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12/16/10 1:15pm - Reply: 'How to remove transmission speedometer gear fitting'
leggomymako
Former Member
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East Hampton, CT - USA

Vette(s):
1975 Corvette with T-Tops

Joined: 10/20/2010
Posts: 27
The speedometer does work when I spin it with a drill, but it is making some rather horrible noises and seems inconsistent in the speed displayed. 

My guess is the speedometer as well, but I may pull off the adapter tonight and have another look at it, and try spinning it with the drill as well.

Thanks for all your help, this is my first Corvette and the first car I have done all the work on myself, so your advice has been really helpful.


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Spending more time under the 'vette than in it since October 2010
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12/16/10 1:19pm - Reply: 'How to remove transmission speedometer gear fitting'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
May have some doo-doo(high tech term) up in the speedo magnet/coil that is making the noise, and causing the speedo to be erratic...

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Joel Adams
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(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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6/17/11 1:00am - Reply: 'How to remove transmission speedometer gear fitting'
theycallmered
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, - Australia

Vette(s):
Second-month production Shark, this 1968E was built up by original owner into 1969 ZR1 (L88 body with LT1 engine) for Club Racing. Body styling is from Maglioli's 1968 L88 "Le Mans" racer

Joined: 10/27/2010
Posts: 54
On a very closely related matter (I don't THINK I'm hijacking the thread), my various manuals are silent on choosing the correct colour speedo gear to match the particular differential gear fitted.  Assuming the same tyre diameter as stock (which mine has, despite the very wide wheels/tyres fitted at the rear), is there available a 'matching chart'?  I believe my car has the AM code / 3.36 rear.

My car also has no speedo cable (retired racer) and I haven't yet popped out the plug that appears to be fitted, so not knowing which, if any, speedo gear is inside.  First I've heard of the adapter, not shown in any of my manuals for the 68 4 speed.


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1968E (2nd month production) convertible first registered California 1967 and a retired SCCA race car.  It is still race prepped and built up as a '69 ZR1 (announced '69 but not built until '70); i.e., the L88 car with LT1 motor.


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6/17/11 11:41am - Reply: 'How to remove transmission speedometer gear fitting'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
The parts manual has a breakdown of available gears for each year, sorted by trans, and diff ratio. It does specify colors on the gears, also.
I could look it up if ya want...it'll take a while, since finding stuff in the parts manual is tedious....and I'm lazy.

SOME 4 speeds may not have an adapter/reducer. I believe some of the earlier Muncies had the speedo on the driver side of the tailhousing, instead of the pass side, as the BW trannys do. The parts manual also states whether or not a given trans/diff/speedo gear combo requires a reducer/adapter, and what ratio it would have if needed....


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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6/17/11 5:52pm - Reply: 'How to remove transmission speedometer gear fitting'
theycallmered
Former Member
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, - Australia

Vette(s):
Second-month production Shark, this 1968E was built up by original owner into 1969 ZR1 (L88 body with LT1 engine) for Club Racing. Body styling is from Maglioli's 1968 L88 "Le Mans" racer

Joined: 10/27/2010
Posts: 54
Thanks!  Your Vette knowledge is quite broad and helps a lot.  Smile  At some point I'll take that plug out and see what I have or don't have inside. 

____________________________________
1968E (2nd month production) convertible first registered California 1967 and a retired SCCA race car.  It is still race prepped and built up as a '69 ZR1 (announced '69 but not built until '70); i.e., the L88 car with LT1 motor.


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