[C2] Speedometer Gear In Transmission
#1
Drifting
Thread Starter
Speedometer Gear In Transmission
How do you determine which one you need?
Vendors have them listed as 18 teeth to 25 teeth, each one is a different color.
Just off a restoration and speedometer is not working.
Speedometer was restored by Ricks and cable is a new repop. i had the trans rebuild but not sure if he replaced the speedometer gear, but there was one in there when i hooked the cable up. I havent pulled the current one out yet.
Car is a 65 coupe with a 4 speed, 396. Originally was a 327/300 hp car.
Thanks!
Vendors have them listed as 18 teeth to 25 teeth, each one is a different color.
Just off a restoration and speedometer is not working.
Speedometer was restored by Ricks and cable is a new repop. i had the trans rebuild but not sure if he replaced the speedometer gear, but there was one in there when i hooked the cable up. I havent pulled the current one out yet.
Car is a 65 coupe with a 4 speed, 396. Originally was a 327/300 hp car.
Thanks!
The following users liked this post:
99Silverbullet (04-15-2019)
#4
Drifting
Hi Patrick,
I just went through this and found the calculators get you close but fine tuning is needed so get a set of gears
Phil
https://www.ebay.com/i/132657059883?chn=ps
I just went through this and found the calculators get you close but fine tuning is needed so get a set of gears
Phil
https://www.ebay.com/i/132657059883?chn=ps
The following users liked this post:
99Silverbullet (04-15-2019)
#5
Race Director
Member Since: May 2000
Location: Redondo Beach USA
Posts: 12,487
Received 1,974 Likes
on
1,188 Posts
You need to specify the installed axle ratio and tire size/revs per mile.
Duje
Duje
The following users liked this post:
lrsgolfer (05-25-2019)
#6
Drifting
Thread Starter
Thanks for the help, i'm going to get the specs today and see what it shows. I went ahead and ordered the gear kit, same price as if i just purchased one from an online corvette parts vendor ..so also thanks for saving me some money!
#7
Drifting
Thread Starter
Update: there was an old gear in there and looked like the opening for the speedo cab was rounded off. Installed a new one and speedo works now.
now I’m off to check the accuracy of the gear.
thanks for everyone’s help.
now I’m off to check the accuracy of the gear.
thanks for everyone’s help.
#8
Drifting
Thread Starter
Revisiting this....I finally got all the major issues fixed on my build and now getting back to the little things.
I started driving the car more and felt like i was driving faster than the speedometer was showing.
Had my wife follow me and it was showing a slower speed.
I downloaded a speedometer app and drove the car and the speedometer is reading about 3-4 mph slower than the app. I have a new gray gear in the trans which is the highest number in the gear kit i bought.
How do i fix this or what is my options.
I live in a neighborhood with school zones all around, so cops will get you for going 5 mph over.
Thanks!
I started driving the car more and felt like i was driving faster than the speedometer was showing.
Had my wife follow me and it was showing a slower speed.
I downloaded a speedometer app and drove the car and the speedometer is reading about 3-4 mph slower than the app. I have a new gray gear in the trans which is the highest number in the gear kit i bought.
How do i fix this or what is my options.
I live in a neighborhood with school zones all around, so cops will get you for going 5 mph over.
Thanks!
#9
Team Owner
Your concerned because a 60 year old mechanical gauge is reading 3 mph low ?
They were prob that far off when new.
Just drive slower thru the school zones.
They were prob that far off when new.
Just drive slower thru the school zones.
#10
Drifting
Thread Starter
I’m sorry but did my post offend you? I thought a new gauge would read more accurate than that.
Last edited by 99Silverbullet; 11-22-2019 at 10:50 PM.
The following users liked this post:
Sky65 (11-27-2019)
#11
Melting Slicks
Just FYI, there are 2 different drive gears available for the transmission output shaft, I believe they are either 8 tooth or 9 tooth. If you really want to get it close, you may have to change that gear, which means tranny comes back out.Personally, I wouldn't worry about it, load a GPS speedometer app on your phone and use if if you want to be more precise.
The following users liked this post:
99Silverbullet (11-22-2019)
#13
Team Owner
Member Since: Apr 2008
Location: Coloring within the lines
Posts: 27,355
Received 1,920 Likes
on
1,333 Posts
Revisiting this....I finally got all the major issues fixed on my build and now getting back to the little things.
I started driving the car more and felt like i was driving faster than the speedometer was showing.
Had my wife follow me and it was showing a slower speed.
I downloaded a speedometer app and drove the car and the speedometer is reading about 3-4 mph slower than the app. I have a new gray gear in the trans which is the highest number in the gear kit i bought.
How do i fix this or what is my options.
I live in a neighborhood with school zones all around, so cops will get you for going 5 mph over.
Thanks!
I started driving the car more and felt like i was driving faster than the speedometer was showing.
Had my wife follow me and it was showing a slower speed.
I downloaded a speedometer app and drove the car and the speedometer is reading about 3-4 mph slower than the app. I have a new gray gear in the trans which is the highest number in the gear kit i bought.
How do i fix this or what is my options.
I live in a neighborhood with school zones all around, so cops will get you for going 5 mph over.
Thanks!
#15
Team Owner
Member Since: Apr 2008
Location: Coloring within the lines
Posts: 27,355
Received 1,920 Likes
on
1,333 Posts
So about 10% low, then.
#16
Drifting
Thread Starter
yep, so if i have a grey 22 in there now drop down a size or go for the blue 20? i have a lift so pretty easy to swap out. thanks
#17
Race Director
#18
Racer
To begin with, how do you know that the speedometer on your wife's car is accurate? You really need to check this with a GPS inside your vette. I use a GPS in multiple vehicles that I own 2015 Toyota, 2019 Toyota, 2005 GMC, 1942 Ford GPW, 1959 Vette, and a 1967 vette. None of them are completely accurate at 35MPH, 65MPH 75 MPH, etc. They all vary by 2-3 MPH. The 67 shows 3MPH faster than the actual speed at 35-40, so I shouldn't worry about tickets. It's better to be in error on the lower speed side than the over the reading. If you want it exact, it may require the removal of the speedometer head to have it recalibrated by a competent shop.
Last edited by 59vetteman; 11-24-2019 at 09:57 AM.
#19
Drifting
Thread Starter
i swapped the gear out with a 21 red today, but discovered a coolant leak where the coolant neck meets the intake, ill post an update after i get the leak fixed, thanks everyone.
#20
Racer
Member Since: Feb 1999
Location: Strongsville Ohio
Posts: 497
Likes: 0
Received 35 Likes
on
17 Posts
I have a similar problem in my '63 with a Powerglide, I think it reads about 10% low and I have the smallest gear I could buy when I did the car. I'd like to fix it but for now just live with it. This was 20 years ago, I doubt there's been any change in the gears available. :/