Transmission vs Speedo Rading

[Glennster]

I went from a 904 to a 727 transmission, I stayed with the 323 rear gear and the same tires (so far). I looks like my speedo is reading a much higher speed than what I'm actually doing. One guy told me something about a plastic gear in the transmission that will effect this. Will the one from my 904 work in my 727? Where is it and how hard is it to change?
THANKS!!!

[Bullitt-]

Yes it will work...changing is a cinch, just make note of the housing position on your 904 & set it the same on your 727.  Its in the tail section drivers side....follow the speedo cable, round disk with #s & marks held in by a clamp..1-bolt

[purple1]

Easy to change, the housing has numbers on it. Just count the teeth and put the housing on with the number of teeth in the correct range.

Dave

[MEK-Dangerfield]

Dave,

  Nice picture.   

I'll be opening my speedo housing tomorrow. Darned leaky O-ring.   

[Bullitt-]

Dave,

  Nice picture.   

I'll be opening my speedo housing tomorrow. Darned leaky O-ring.   

There is an internal seal also...I got one from Oreilly's speedo gear lip seal p# 760010-5  .69    they stock

[BIGSHCLUNK]

Dave,

  Nice picture.   

I'll be opening my speedo housing tomorrow. Darned leaky O-ring.   

Mike, you ain't done with that yet??           

[Bullitt-]

Mike, you ain't done with that yet??           

Still needs to paint his pan Purple

[Glennster]

Nobody told me I'd need to paint my pan purple. Why am I always the last one to hear this stuff?!?!?!?
I thought I got all the fluid out of my old 904 before I brought it home, as you can see by the mess in the melted snow, there was still some blood in the old girl.......

Will I need to position the numbers on the 727 plate the same as the one on the 904?
What do the numbers mean?
Should I take this plate off the 904 and put it on the 727 or doesn't that matter???
One more maybe dumb question, will fluid come out of the 727 when I remove this plate, or does the fluid rest below the plate?
THANK YOU for all the help Gentlemen!!!



#28 must be for a tall rear gear.....

[Bullitt-]

See the line at the bottom with 26-31   there is a dot below ...your gear is a 28 so that's the line. ...the 904 will work..... Purple paint 1/2 price at Advanced Auto Parts today

[purple1]

Nobody told me I'd need to paint my pan purple. Why am I always the last one to hear this stuff?!?!?!?
I thought I got all the fluid out of my old 904 before I brought it home, as you can see by the mess in the melted snow, there was still some blood in the old girl.......

Will I need to position the numbers on the 727 plate the same as the one on the 904?
What do the numbers mean?
Should I take this plate off the 904 and put it on the 727 or doesn't that matter???
One more maybe dumb question, will fluid come out of the 727 when I remove this plate, or does the fluid rest below the plate?
THANK YOU for all the help Gentlemen!!!


#28 must be for a tall rear gear.....

Oh yeah... The special purple paint keeps out gremlins.   

You may get a little bath, be ready for it.  A #28 sounds about right for a 3.23. I think mine was a #28 or #29.

Dave

[the_engineers]

If you do this with the car "level", just a few drops will come out.  If you do this with the front wheels jacked up, you'll take a bath.

[Glennster]

I'll get a little lift on the rear before I pull it apart.
 Now I see know how this works, the plate with the numbers rotates and moves the center line of the shaft so different size gears will fit properly.
GOT IT ! ! !
The 727 tranny that is in the car now must have been set up for a real short rear gear, the speedo said I was going 70 MPH and I don't think I was doing more than 50. I hope to get it apart tomorrow afternoon....... Can't wait to see what I find!
THANKS for all the help ! ! ! ! !

[the_engineers]

If it's a 38 or 39, I'll take it.

[Glennster]

 I jacked up the rear end, crawled under there and removed a 29. I put the 28 from my 904 in the 727. It was too wet to go for a ride. When weather permits, I'll go for a ride with the GPS and see how accurate the speedo is. I don't know how big a difference one tooth on the gear can make......
 

[70burntorangeT/A]

I jacked up the rear end, crawled under there and removed a 29. I put the 28 from my 904 in the 727. It was too wet to go for a ride. When weather permits, I'll go for a ride with the GPS and see how accurate the speedo is. I don't know how big a difference one tooth on the gear can make......
 

dont think it will make much at all. Did you recently swap gauges? Because when i swapped from standard to rallye i had the same problem, it said i was going much faster then i really was