New speedo drive won't work

[TimDart]

Just fitted a new 39 tooth (Blue) speedo drive to my trans tail shaft. Nothing registers on the dashboard.
I fiited it correctly and have fited two in the past without problems
Application is small block/727 + 3.91 rear.
Can anyone help, dont want to get busted!

 

[MVRCorp]

Mine hasn't worked since I went thru the tranny last winter. Turns out the little metal pin in the end of the speedo gear fell out and got lost. I've been looking for one ever since. Check to make sure your's is in place.

Jim

 

[Longgone]

The speedo gear housing has 3 positions to clock the gear. Make sure the housing is in the 39-45 position with the index mark for that position at 6 o'clock. HTH.

 

[TimDart]

Longone, when you sat 'location mark', can you be alittle more specific? Its fited at the right number, I have the correct number range at 6 o'clock. Is that correct, or is there an alternative marker that should be lined up?

 

[Longgone]

The number range should be in the 6 o'clock area but the small index mark (which is off to one side a little, but still in the range) should be what`s exactly at 6 and corresponding with the mark on the transmission housing.

 

[TimDart]

Thanks Longone, thats whee I went wrong. The diagram in my manual indicated that the number are the location. Previously i did what you suggest.
Too dark now, do you reckon i've screwed up the new drive?

 

[Longgone]

No, I think the drive should be okay, since it didn`t work it probably didn`t make contact with anything. Check the connection at the speedometer too , the 69 and up cars have a plastic clip that`s well known for slipping off. At the trans gear ,when you get it clocked correctly the index mark on the gear housing will be right at 6 oclock and aligned with a mark on the transmission case. The two ends of the wishbone shaped retainer (that holds the gear housing in place) will also lock into corresponding grooves in the gear housing.

 

[TimDart]

Checked, refitted and correct and still not working. I suspect a broken cable. I can turn the speedo drive by hand in either direction. surely i should meet resisitance in at least one direction?
There is no damage to the drive so i,m sure its a correct install. Suspect its spinning a broken cable around.
The speedometer is from a /6 so i have wound it off the clock (beyond 100mph) so the cable must have been getting some stress.
Is this a possibility?

 

[mullinax95]

Mine hasn't worked since I went thru the tranny last winter. Turns out the little metal pin in the end of the speedo gear fell out and got lost. I've been looking for one ever since. Check to make sure your's is in place.

Jim

Actually there is no metal pin. I thought the same thing and tried to fish it out of the transmission but can't fish anything when is does not exist.

Checked, refitted and correct and still not working. I suspect a broken cable. I can turn the speedo drive by hand in either direction. surely i should meet resisitance in at least one direction?
There is no damage to the drive so i,m sure its a correct install. Suspect its spinning a broken cable around.
The speedometer is from a /6 so i have wound it off the clock (beyond 100mph) so the cable must have been getting some stress.
Is this a possibility?

The speedo drive should not move at all. Keep trying.

I would take the cable out of the speedo cable housing and inspect it. I took mine out of the part attached to the trans and cleaned it and added grease to it before sliding it back in.

 

[Longgone]

Checked, refitted and correct and still not working. I suspect a broken cable. I can turn the speedo drive by hand in either direction. surely i should meet resisitance in at least one direction?
There is no damage to the drive so i,m sure its a correct install. Suspect its spinning a broken cable around.
The speedometer is from a /6 so i have wound it off the clock (beyond 100mph) so the cable must have been getting some stress.
Is this a possibility?

The cable is usually the first thing to go, it`s a good chance that`s where your problem lies.

 

[rick_rawker]

The speedo gear housing has 3 positions to clock the gear. Make sure the housing is in the 39-45 position with the index mark for that position at 6 o'clock. HTH.

Thanks so much for this information you shared back then. I was able to get my son's speedometer working by clocking it correctly.

CHEERS, Rick

 

[Longgone]

Thanks so much for this information you shared back then. I was able to get my son's speedometer working by clocking it correctly.

CHEERS, Rick

You`re welcome Rick, that`s what it`s all about here. I probably spend more time in the archives than in the present day posts myself.