Author Topic: Speedo Cable Color  (Read 1916 times)

David K

  • Hero Member
  • *****
  • Posts: 1138
  • Dr. Longblock
    • View Profile
Re: Speedo Cable Color
« Reply #15 on: September 04, 2023, 03:34:51 PM »
Dunno…can’t hurt.

dannystarr

  • Hero Member
  • *****
  • Posts: 1745
    • View Profile
Re: Speedo Cable Color
« Reply #16 on: September 30, 2023, 05:35:56 PM »
Well, I got it figured out. It had a 23 that was WAY off. I tried a 22 and it fixed it by 5MPH. Then I tried a 21 and an 18 and it seemed to go the wrong way. Then 20 tooth and BINGO, DEAD ON. It read perfect from 25 to 65. I was amazed how accurate it was. At 70MPH on the speedo, it read by satellite at 72. That was the only real change. And I won't be going that fast or above that speed. I was mainly concerned from 40 to 60. So if you have a M21 - 3:73 and are running Good Year E70/15's, this would be a good starting point for accuracy. Going to check some of my other cars and see what happens. I am shocked GM missed it by that much. But maybe some things changed in thousands of miles? The internal gear was in nice shape. And the 23 tooth I took out was also perfect?  Danny 

169INDY

  • Hero Member
  • *****
  • Posts: 1794
    • View Profile
Re: Speedo Cable Color
« Reply #17 on: October 01, 2023, 01:02:37 AM »
Great News "D".

Blue Right? (Gear)
Good info
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS
68 Z28 M21 LOS

David K

  • Hero Member
  • *****
  • Posts: 1138
  • Dr. Longblock
    • View Profile
Re: Speedo Cable Color
« Reply #18 on: October 01, 2023, 02:53:26 AM »
Glad you got it dialed in. I'm curious how you think GM got something wrong.

rare396bronze

  • Member
  • ***
  • Posts: 283
    • View Profile
Re: Speedo Cable Color
« Reply #19 on: October 01, 2023, 05:09:48 AM »
The drive gear might had been changed inside the transmission sometime. The might had put the wrong tooth count gear back in!  The black gear should been right. I just told you abought the other gears so you didn't have to take off the tailshaft. Glad it worked.

dannystarr

  • Hero Member
  • *****
  • Posts: 1745
    • View Profile
Re: Speedo Cable Color
« Reply #20 on: October 02, 2023, 02:25:58 AM »
 Indy - Yes, Blue Gear....

 DK - If it has the factory set-up GM should have made sure it was accurate. Contact Muncie and work it out.

 Bronze - When the trans was pulled for inspection and clutch install, it looked to have never been opened up. The side cover
 gasket was original. Everything inside was in good original shape. Maybe they pulled it apart at the tail shaft? I believe I am the
 3rd owner and the car sat for almost 30 years. I am going to guess it was never apart. Who knows, I am curious to see what
 happens with some other cars. Maybe I'll post my findings. Just glad it is very accurate now. Thanx for the suggestion on gear 6-
 pack. ... Danny