Speedo gear issues
Thread Starter
Heel & Toe
Joined: Jan 2024
Posts: 20
Likes: 3
Speedo gear issues
I have a 4 Speed M21 with Speedo gear issues. So I’m finally tackling a problem with my speedometer not working, and I’ve narrowed down the possible issues. The cable and the gauge itself works, using the drill to spin the cable, so that means it’s the adapter or the gears in the trans. So next I put the car on jacks and let the back wheels spin in 1st and saw that the driven was NOT spinning. So the drive and driven gears aren’t meshing.
I also noticed that I could wiggle the driven gear by turning it while in the transmission.
Im fairly sure the drive gear is not on the right spot, which means I’ll have to pull the tail housing/ trans. Do you think that’s necessary? I don’t want to go thru all that work just for it to be something else.
I also noticed that I could wiggle the driven gear by turning it while in the transmission.
Im fairly sure the drive gear is not on the right spot, which means I’ll have to pull the tail housing/ trans. Do you think that’s necessary? I don’t want to go thru all that work just for it to be something else.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,209
Likes: 9,348
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
some trans used a plastic gear and you have to pull it apart to fix it...best repair is pressing on a steel one
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,209
Likes: 9,348
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
your best bet is to go through pauls videos and watch the repair part you need...if i can fins it real quick I will add that link
go to 23:30 hes talking locations and how to do it...
this video is basically the same info but good info because you might hear something a different way
6:50 mark
this video is basically the same info but good info because you might hear something a different way
6:50 mark
Last edited by Rescue Rogers; May 10, 2024 at 08:52 AM.
Thread Starter
Heel & Toe
Joined: Jan 2024
Posts: 20
Likes: 3
Upon closer inspection of my old driven plastic gear, it seems to only be contacting in the very outer edge of the gear. This means that the drive gear has been slipping and in one spot it even slightly ate into the plastic driven gear. Measuring on the thickest part of the plastic driven gear I get a 0.78” diameter while gears I see online are 0.81”… maybe this could solve my problem of the teeth being too far apart?
