C3 Vette Registry - The Best Resource on the Net for C3 Vettes! C3 Vette
Forums -> C3 Driveline Components
Not Logged In! Login or Register!  Users Online: 16 / Help 
Features  Find C3 Parts on ebay in only 2 or 3 clicks!  | Add YOUR C3 to the Registry

Supporting Vendors
Volunteer Vette Products
Mid America Motorworks
CorvetteClothing.com
Bair's Corvettes
VetteBookStore.com

C3 of the Month
None Current
Enter Yours Today!
Online C3 Show
13
C3s are Registered

Vanity Plates
LYNNE73
Lynne73
Featured Links

Buy Now
Corvette by the Numbers
Corvette by the Numbers


The Corvette Factories: Building America's Sports Car (Hardcover)
The Corvette Factories: Building America's Sports Car (Hardcover)


How To Rebuild Corvette Rolling Chassis 1963-1982
How To Rebuild Corvette Rolling Chassis 1963-1982


The Corvette Dynasty (Hardcover)
The Corvette Dynasty (Hardcover)



| Hide Signatures and Profile Pics

 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
3/2/12 5:33pm - Original Message: 'Calibrating Speedometers'
tb2k82ce Lifetime Member
Lifetime Member
- Send Private Message


Lemon Grove, CA - USA

Vette(s):
1982 C3 Collectors Edition 44000 miles, sat in the sun most of it's life, My wife purchased it for me for fathers day in 2007 from her girl friend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.

Joined: 10/17/2007
Posts: 2007
My speedometer was running about 10% high which on an 85 mph Speedo get you peg real quick. Beer
The gear housing on my C3 was leaking a little so I had them replace it and in about 10 miles my Speedo quit.  Took it back to the shop and the plastic gear shaft snapped off.   Shocked Good time to calibrate the Speedo.  Found info on how to select the gears. But finding the correct size was difficult I finally found a 44 tooth gear had it put in ran it on the dino and the car was doing 60 with speedo reading 61mph.  Good to go.  Took it on the road 5 miles later speedo stopped working back to the shop speedo gear shaft snapped off again. 
Guess what speedo gear housing come in two sizes one for 34-41 and then for 42-15 tooth gears.  42-45 will fit but when the housing gets a little hot snap goes the shaft.  Not a big problem they are only $11 lesson learned.  Not happy but no major damage. 
Wrongthere are no more 44 tooth gears that I could find in the world.  I happened to have purchased the last one.  
There is good news and that what I wanted everyone who may have gone through this and it is that Transmissioncenter.net is manufacturing the complete range of speedo gears now that GM quit doing it.  There delivery scheduled to start in early spring 2012.  They plan on selling them for $11 each just as before.  Thumbs Up
So if you have gone through this issue you may want to revisit it in the summer when the gears are again available in large supply.


____________________________________
 
 Reply Reply  Quote Reply w/Quote
 
Support C3VR!
Suport our advertisers
3/3/12 9:51am - Reply: 'Re: Calibrating Speedometers'
manget1 Lifetime Member
Lifetime Member
- Send Private Message


Indianapolis, IN - USA

Vette(s):
Silver 1974 Convertible - L82 4 speed Low miles (was only 8,900 when I bought it in March 2006) - Now 42K miles. Original owner bought it as an investment for son's college expenses. 2008 Jetstream Blue Convertible - DAILY DRIVER!!

Joined: 9/3/2006
Posts: 2382
Thanks for sharing so that others hopefully don't have to go through the trouble and frustration you have!

____________________________________
I wanted a Corvette my whole life, but I never dreamed of all the wonderful people I would meet because of it!

      States Visited Map

target=_blank>Click for another pic!     And yet another!
 Reply Reply  Quote Reply w/Quote
3/3/12 10:25am - Reply: 'Re: Calibrating Speedometers'
Adams' Apple Lifetime Member
Lifetime Member
Moderator
- Send Private Message


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: 19447
The difference in the housings is that the hole for the gear/cable is off-set, to allow for the different diameter/tooth count gears. Incorrect usage will either break the gear, as Gilbert discovered, or will shred the teeth of the gear quickly. One way puts too much pressure on the gears, and the other puts the gears too far apart.

One thing that could be done, if you find yourself in this predicament, is to turn the housing in the tail, until the gear mesh is correct. The hold-down bracket will not fit into the slots for it very well like this, but it will get you down the road with no speedo issues, and you won't have to get another housing, or gear.

This scenario(speedo gear housing differences) can be had on either the 400, or 700 trannys. The 350(Chevy), and 4 speed trannys use the small "bullet" style speedo housings, and those are all the same.

Thanks for the post, Gil!Thumbs Up


____________________________________
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"
 Reply Reply  Quote Reply w/Quote
3/3/12 5:57pm - Reply: 'Re: Calibrating Speedometers'
tb2k82ce Lifetime Member
Lifetime Member
- Send Private Message


Lemon Grove, CA - USA

Vette(s):
1982 C3 Collectors Edition 44000 miles, sat in the sun most of it's life, My wife purchased it for me for fathers day in 2007 from her girl friend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.

Joined: 10/17/2007
Posts: 2007
So it is not so much the shaft size although the smaller gear shaft move a little easier than the larger gear shaft did.  that they are off set a little make it work for me as the shear point in both casees was next to the gear.  Luckly I do not see any damage to the drive gear.  I looked real close.  I know all of the other transmissions that take this set up which is why the after market company is making the investment in them.   The engineer said he expected my size to be in in a couple of weeks but he wanted to run test on them to make sure they would last.  He stated that they tried metal ones and that did not work out good when tested. 

____________________________________
 
 Reply Reply  Quote Reply w/Quote
 New Topic New Topic Post Reply Reply New Poll New Poll Search     Search Page [1]  
 Forums -> C3 Driveline Components
(Moderator: Adam Wartell, Norsky, Adams' Apple)
 

 
Official C3 Vette Registry Community:
Home | Forums | Email | Who's Online | Clubs | Events | Member Stats

Other Official C3 Vette Registry Areas:
Members | Research | Shop | My Account | About C3VR
 

Corvette is a registered trademark of the General Motors Corporation(GM) & Chevrolet Motor Division. Vette Registries, LLC is responsible for all site content (except for member submitted content or where otherwise noted) and does not claim or imply that Chevrolet or GM is responsible for Official C3 Vette Registry content. Vette Registries, LLC is independent from GM and is not affiliated with, sponsored or supported by GM.  Copyright/trademark/sales mark infringements are not intended, or implied and are in fact used to support GM, Chevrolet and Corvette

Official C3 Vette Registry content is Copyright 2001-2017, Vette Registries, LLC. Content may not be reused without written consent. All Rights Reserved. NS

Corvette (Vette) Model Years on this site: 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 30