Author Topic: Speedometer gear  (Read 1184 times)

0 Members and 1 Guest are viewing this topic.

Offline sjfd04

  • Crazy about Buick!
  • *****
  • Posts: 279
Speedometer gear
« on: January 14, 2012, 03:47:39 PM »
I need to know what speedo gear to use.  I have an automatic with a 40 tooth speedo gear.  My speedometer reads slow, about 5 mph.  Do I need a 41 tooth or 39 tooth?    In addition, where can I buy one?  I did purchase a gear from The Parts Place but it was the wrong one.


thanks, Tom
65 GS 4-Speed Hardtop
2017 Chevy Silverado HD 2500
1970 1/2 Camaro Z-28 4-speed

Offline Brian

  • Global Moderator
  • Crazy about Buick!
  • *****
  • Posts: 1096
Re: Speedometer gear
« Reply #1 on: January 15, 2012, 07:08:29 PM »
Less teeth on the driven gear will make the speedo read faster.  So get a 39 tooth and try that.
'64 Skylark 2dr ht 4 speed, 300-4
'65 GS ht, 4 speed,2-4s,AC,PS,PB,PW,Pseat,Tilt
'66 Skylark 2dr ht 300-2 automatic
'78 Yamaha DT 400 2 stroke
'88 Ford F-150 4x4 (used to be 4x2)
'89 Ford F-350 4x4
'03 Honda Accord Coupe V6 6-speed manual (daily driver)

Offline sjfd04

  • Crazy about Buick!
  • *****
  • Posts: 279
Re: Speedometer gear
« Reply #2 on: January 15, 2012, 07:20:28 PM »
Well, I tried that, the problem was that the gear I got from the Parts Place was smaller in diameter.  I bought 37 38 and a 39 , all the same diameter just the different tooth count.  My 40 tooth is larger and the other gears will not contact the drive gear in the trans. The parts Place indicated the gears I bought were correct for the ST 300.
65 GS 4-Speed Hardtop
2017 Chevy Silverado HD 2500
1970 1/2 Camaro Z-28 4-speed

Offline WkillGS

  • Administrator
  • Crazy about Buick!
  • *****
  • Posts: 2039
Re: Speedometer gear
« Reply #3 on: January 15, 2012, 07:56:15 PM »
Sounds like you have the wrong sleeve, or gear holder. They are made to fit a certain range of gears.
There were 2 different ones used on '66 GS. I'd expect '65 to be the same.
pn 1362284 fits 34, 35, 36, 37, 38, and 39 tooth gears.
pn 1362285 fits 40, 41, 42, 43, 44, and 45 tooth gears. 
For drive gears, a 16 or 17 tooth gear was used.



Walt K
Eastern Pa

66 GS Astro Blue/blue 425 auto
66 GS Silver Mist/black 401 4 spd
66 GS Flame Red/black 401 5 spd
66 GS Saddle Mist/black 401 L76 auto
66 Special Flame Red/black 300 5 spd
65 GS vert Verde Green/ Saddle buckets 401 4 spd
79 Turbo Regal

Offline sjfd04

  • Crazy about Buick!
  • *****
  • Posts: 279
Re: Speedometer gear
« Reply #4 on: January 15, 2012, 08:09:58 PM »
Thanks for the info, I found what I need on Ebay.

Tom
« Last Edit: January 15, 2012, 10:38:49 PM by sjfd04 »
65 GS 4-Speed Hardtop
2017 Chevy Silverado HD 2500
1970 1/2 Camaro Z-28 4-speed