C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Speedo gear question.

Thread Tools
 
Search this Thread
 
Old Jul 14, 2011 | 02:33 AM
  #1  
scottyp99's Avatar
scottyp99
Thread Starter
Le Mans Master
15 Year Member
 
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Default Speedo gear question.

Hi, all,
My speedo doesn't like to work for about 1/2 to 1 mile when I first start driving it, then the speedo jumps around for a minute or so, and then works normally. Also, there is a leak from the speedo gear on the tranny.
I will be under the car in that general area anyway soon, (tranny mount replacement) and I figure I'll replace the seals, but can somebody tell me what else I should be doing "while-I'm-at-it". Thanks,


Scott
Reply
Old Jul 15, 2011 | 02:34 PM
  #2  
pawpaws toy's Avatar
pawpaws toy
Burning Brakes
Supporting Member
15 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Jun 2011
Posts: 817
Likes: 11
From: lewisburg wv
Default

Originally Posted by scottyp99
Hi, all,
My speedo doesn't like to work for about 1/2 to 1 mile when I first start driving it, then the speedo jumps around for a minute or so, and then works normally. Also, there is a leak from the speedo gear on the tranny.
I will be under the car in that general area anyway soon, (tranny mount replacement) and I figure I'll replace the seals, but can somebody tell me what else I should be doing "while-I'm-at-it". Thanks,


Scott
While speedo cable is un-hooked, run the speedo with a drill to see if you have the same problem. If not, check the speedo DRIVEN gear. You need to take its housing off anyway to replace that leaky O ring. While you're at it, use a light and peek inside and check the condition of the DRIVE gear.
Reply
Old Jul 15, 2011 | 03:12 PM
  #3  
scottyp99's Avatar
scottyp99
Thread Starter
Le Mans Master
15 Year Member
 
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Default

Originally Posted by pawpaws toy
While speedo cable is un-hooked, run the speedo with a drill to see if you have the same problem. If not, check the speedo DRIVEN gear. You need to take its housing off anyway to replace that leaky O ring. While you're at it, use a light and peek inside and check the condition of the DRIVE gear.
Sounds good, thanks for the info, brother!

Scott
Reply
Old Jul 15, 2011 | 04:39 PM
  #4  
scottyp99's Avatar
scottyp99
Thread Starter
Le Mans Master
15 Year Member
 
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Default

OK, now that I kinda know what I am removing is supposed to look like, I am thinking that, as long as I have it apart, I might as well replace the bullet seal, the speedo gear seal, and the driven speedo gear itself. I don't want to take it apart, and then order parts. I want to order parts, recieve them, and then disassemble and reassemble, ya dig? Now, I have spent the last hour or so trying to figure out how to order the parts.

1.) Can anybody tell me of a place that will sell me the bullet seal, (o-ring) the driven gear seal, (lip seal) AND the driven speedo gear?
Also, I have no idea what speedo gear to purchase! My differential is a Dana 44 with 3.07 gears.

2.) Plan of attack:
a.)Put car up on jackstands.
b.)Support tranny weight with jack.
c.)unbolt tranny crossmember.
d.)Deal with speedo housing.
e.)bolt up crossmember.
f.)replace tranny mount.
g.)Remove jack.
h.)Remove jackstands.
i.)Drive car and enjoy working, leak-free speedometer.


Question, comments, or concerns?

Scott
Reply
Old Jul 15, 2011 | 06:15 PM
  #5  
Timsride's Avatar
Timsride
Burning Brakes
 
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
Default

You will pretty much need to pull the speedo gear which can be done by just lifting corner of car slide under car. Remove cable and then there will be one bolt holding plastic gear and seal in place. If your gear is pooched you can order one from GM, or supporting vendor. They are colour coded so they will probably want to know which one assuming your speedo was accurate to start with. Nice new avatar by the way I almost didnt realize who it was.
Reply
Old Jul 15, 2011 | 06:30 PM
  #6  
scottyp99's Avatar
scottyp99
Thread Starter
Le Mans Master
15 Year Member
 
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Default

Originally Posted by Timsride
You will pretty much need to pull the speedo gear which can be done by just lifting corner of car slide under car. Remove cable and then there will be one bolt holding plastic gear and seal in place. If your gear is pooched you can order one from GM, or supporting vendor. They are colour coded so they will probably want to know which one assuming your speedo was accurate to start with. Nice new avatar by the way I almost didnt realize who it was.
I finally gave up on Q-jets for awhile, put a Holley on, so I figured I should change the avatar.

I'd like to have the gear on hand when I begin the work, can anybody tell what color gear is needed for which rearend gear? 1980 Corvettes only came with one rear end gear, 3.07, and one automatic transmission, th350, so there should only be one to choose from.

I will be replacing tranny mount at the same time, so I might need a little more room than that, and it sure looks cramped in there, I can't get my hand or a tool in there to do anything with the speedo connection, gonna need some room, so I'll move the cross member a little if I need to. See ya,

Scott
Reply
Old Jul 15, 2011 | 08:17 PM
  #7  
pawpaws toy's Avatar
pawpaws toy
Burning Brakes
Supporting Member
15 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Jun 2011
Posts: 817
Likes: 11
From: lewisburg wv
Default

clear, 17 tooth
Reply
Old Jul 16, 2011 | 04:05 PM
  #8  
scottyp99's Avatar
scottyp99
Thread Starter
Le Mans Master
15 Year Member
 
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Default

Originally Posted by pawpaws toy
clear, 17 tooth
Thanks, brother!!

Scott
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

 Michael S. Palmer
story-1

5 Best & 5 Worst Corvette Daily Drivers

 Joe Kucinski
story-2

The Headlights of Every Corvette Generation Explained

 Joe Kucinski
story-3

5 Best & 5 Most Overrated Corvette Track Packages of All Time!

 Joe Kucinski
story-4

Every 2027 Corvette Engine Explained

 Joe Kucinski
story-5

Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

 Verdad Gallardo
story-6

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-7

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-8

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-9

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
Old Jul 16, 2011 | 05:51 PM
  #9  
Johan74's Avatar
Johan74
Racer
15 Year Member
 
Joined: Jan 2007
Posts: 308
Likes: 18
From: Sweden
Default

Originally Posted by scottyp99
1.) Can anybody tell me of a place that will sell me the bullet seal, (o-ring) the driven gear seal, (lip seal) AND the driven speedo gear?
Also, I have no idea what speedo gear to purchase! My differential is a Dana 44 with 3.07 gears.
Check this guy out for speedo gears!
http://www.transmissioncenter.org/GM...eter_Gears.htm

Johan
Reply

Get notified of new replies

To Speedo gear question.





All times are GMT -4. The time now is 12:46 PM.

story-0
2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

Slideshow: Is the 2027 Chevrolet Silverado 1500 the best Silverado yet?

By Michael S. Palmer | 2026-06-16 08:01:12


VIEW MORE
story-1
5 Best & 5 Worst Corvette Daily Drivers

Slideshow: 5 best and 5 worst Corvette daily drivers

By Joe Kucinski | 2026-06-15 10:32:13


VIEW MORE
story-2
The Headlights of Every Corvette Generation Explained

Slideshow: The headlights of every Corvette generation explained

By Joe Kucinski | 2026-06-15 10:17:14


VIEW MORE
story-3
5 Best & 5 Most Overrated Corvette Track Packages of All Time!

Slideshow: The 5 best and 5 most overrated Corvette track packages ever.

By Joe Kucinski | 2026-06-09 12:46:45


VIEW MORE
story-4
Every 2027 Corvette Engine Explained

Slideshow: Every 2027 Corvette engine explained

By Joe Kucinski | 2026-06-09 12:16:31


VIEW MORE
story-5
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.

By Verdad Gallardo | 2026-06-08 19:53:43


VIEW MORE
story-6
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-7
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-8
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-9
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE