speedo question

[Farmer Joe]

so ive had the 5 speed in the truck for about 2 weeks and and its been working great, but i want my speedo to be right again.

 

now i understand that the speedo drive will come out of the trans. but can i put the speedo drive from the auto into the 1980 5spd? or do i have to take the whole tail case off the transmissions to swap out the ring gear too?

 

any help would be great!

 

thanks

[datto510]

Did your truck have a 4 speed before? If so, I believe you put the 4-speed cog into the 5-speed to make the speed-o-meter work right...........Who needs a speedometer anyway?

[ggzilla]

You do not need to change the driving gear, just the gear that comes out the side. There are four or five ones that fit. If you need to go further then the driving gear can be changed.

 

I doubt if the ones from automatic will fit manual transmission

[datzenmike]

Beware a tranny made from about '80 and up, the earlier speedo drives won't fit it. (the speedo drive is the plug with the plastic gear on the end that bolts into the tailstock) Take a look at the 10mm bolt that holds the keeper in the slot in the side of the speedo drive. If it is at 12 o'clock then it is an early tranny and will fit only trannys made until '80. If the bolt is at the bottom 6 o'clock position, it is a newer box and will only take the newer speedo drives.

 

FS5W71B, F4W71B and 3N71B automatic drives are interchangeable.

Edited March 22, 2009 by datzenmike

[Farmer Joe]

mkay.

 

well the automatic is the original for the truck. its a 12/76 truck so its a 77 model year.

 

the 5 speed is from a 1980 2wd 720 that had an l20b. i dont know the build date but i know it was an 80.

 

so would those transmissions have interchangeable speedo drives?

[ggzilla]

I bought my gears without the "drive" so I reckon you can swap them:

 

two speedo gears (white and blue)

[Farmer Joe]

well im still curious on whether the speed dive will swap from a 77 auto to an 80 5 speed?

 

thanks

[datzenmike]

Not supposed to. Late '79 and up were installed with the key way facing down. Pre '80s had the key way facing up. If you swap them, one won't engage the drive teeth and the other will be squashed.

 

Here's a picture of the difference:

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/transcogs.jpg[/img]"]

[ggzilla]

Can you remove the gear from the auto cog-body, and put it in the manual cog-body?

[Farmer Joe]

well from the picture, it looks like it will work. the auto is a 77 and the 5 speed is an 80.

 

i guess ill just pull em and see if they swap. ill break in my new garage with that task!