• Community Forums
  • Regional Forums and Event Information

Speedometer replacement

  • Thread starter Thread starter 89OctaneStang
  • Start date Start date Sep 2, 2007

89OctaneStang

New Member
Aug 1, 2007
12
0
0
Ft Lewis, WA
Sep 2, 2007
#1
  • Sep 2, 2007
  • #1
Well, I just replaced my 85 MPH speedo with a 140 MPH speedo. But now I'm having problems getting it to read right. I changed my original 18 tooth gear set to a 23 tooth gear set and it didn't fix the problem. And when I took the 23 tooth gear out today, the gear teeth had been broken while inside the trany during that short period of time. Has anyone worked on their speedo before and experienced something similar to this and found the fix to the problem? Cause I'm clueless at this point....
 

white 89 GT

Member
Apr 3, 2003
281
0
17
Tacoma
Sep 3, 2007
#2
  • Sep 3, 2007
  • #2
For now put in a 20 or a 21. the 21 may not last long also.
Basically im saying put the highest count gear in that will last till you can change some internals (7 tooth output shaft) then save your dollars for some trans upgrades like the ones I did to mine.
 

04MystiCobra

New Member
Jan 29, 2004
12
0
0
Corpus Christi, TX.
Sep 3, 2007
#3
  • Sep 3, 2007
  • #3
Theres no other way other than to go into the tranny? Just doesnt sound right. There are so many out there that have done this swap (not me) and I havent read that. I dont see many foks willing to do this if you gotta go in the tranny.
 

white 89 GT

Member
Apr 3, 2003
281
0
17
Tacoma
Sep 3, 2007
#4
  • Sep 3, 2007
  • #4
I think someone makes a add on speedo correct gadget.
PAT performance automatic trans. look it up on the web
 

89OctaneStang

New Member
Aug 1, 2007
12
0
0
Ft Lewis, WA
Sep 3, 2007
#5
  • Sep 3, 2007
  • #5
Well, I just went to the guys house I bought the 140 from and got my 85 from him off his bench. Checked the back of the needle and seen that there is a weight there that I dont have on the 140 speedo. So tomorrow after work I'm going to tear apart my dash again and put the needle from my 85 onto the 140 and see if it makes any difference. And then I'm going to put the 18 tooth gear set back on since that worked perfectly for the car and see where that leaves me.. I'll keep you all informed of what progress I find through doing this.
 

white 89 GT

Member
Apr 3, 2003
281
0
17
Tacoma
Sep 4, 2007
#6
  • Sep 4, 2007
  • #6
Check my previous post
 

89OctaneStang

New Member
Aug 1, 2007
12
0
0
Ft Lewis, WA
Sep 4, 2007
#7
  • Sep 4, 2007
  • #7
Do I need that part???

If so, where can I get one????????
 

white 89 GT

Member
Apr 3, 2003
281
0
17
Tacoma
Sep 4, 2007
#8
  • Sep 4, 2007
  • #8
89OctaneStang said:
Do I need that part???

If so, where can I get one????????
Click to expand...

I think it will help correct your speedo and can be found at PATC AOD trans, then look around till you find speedo adaptors and click on the link and scroll down to aod adaptors.
 
You must log in or register to reply here.

Similar threads

Drivetrain Speedo gear ate itself
  • keel
  • Aug 15, 2024
  • Fox 5.0 Mustang Tech
Replies
7
Views
696
Fox 5.0 Mustang Tech Aug 15, 2024
AeroCoupe
J
'96 Cobra: A/C gets weak and engine misfires under load when warm
  • jruhnke
  • Oct 22, 2025
  • SVT Tech Forum
Replies
2
Views
265
SVT Tech Forum Nov 20, 2025
nickyb
6
Hey all,I’m putting together a 302 for my 1968 Mustang and wanted to post the combo + some questions to make sure I’m not missing crucial
  • 68_Disgustang
  • Feb 22, 2026
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
3
Views
640
1965 - 1973 Classic Mustangs -General/Talk- Feb 28, 2026
Noobz347
M
Progress Thread mkk50's Progress Thread
  • mkk50
  • Aug 4, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
19
Views
673
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Sep 22, 2025
Noobz347
Drivetrain 83’ Glx convertible C5 Trans help!
  • JacksonJared2113
  • Dec 25, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
318
Fox 5.0 Mustang Tech Dec 26, 2025
JacksonJared2113
Share:
Bluesky Email Share Link
  • Community Forums
  • Regional Forums and Event Information
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?