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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech

What speedo gear for 3.90's?

  • Thread starter Thread starter jonnystang
  • Start date Start date Nov 24, 2006
J

jonnystang

New Member
Oct 31, 2006
14
0
0
Littleton, CO
Nov 24, 2006
#1
  • Nov 24, 2006
  • #1
Hey all just wondering what speedo gear would be correct for my 3.90's. I have had the gears in for almost a year and am just getting sick of all the extra miles and the wrong speedometer reading. Thanks again for you help.
 

legalize420

Active Member
May 21, 2005
1,541
1
37
South Florida
Nov 24, 2006
#2
  • Nov 24, 2006
  • #2
the 5.0 tech section has a whole list of speedo gear combinations. 6 tooth drive gear and a 19 tooth speedo gear for 3.90. the tranny needs to be opened up. the drive gear is on the mainshaft.
 

The Green GT

No 13 year olds are safe around me.
10 Year Member
Jan 8, 2006
1,269
19
99
Louisiana
Nov 24, 2006
#3
  • Nov 24, 2006
  • #3
Do it right and spend the $100 and get a speedcal.
 

SeventyMach1

Keep it lubed .... keep it straight .... and keep
Mar 30, 2005
1,940
3
36
North Carolina
Nov 24, 2006
#4
  • Nov 24, 2006
  • #4
legalize420 said:
the tranny needs to be opened up. the drive gear is on the mainshaft.
Click to expand...


 

legalize420

Active Member
May 21, 2005
1,541
1
37
South Florida
Nov 24, 2006
#5
  • Nov 24, 2006
  • #5
SeventyMach1 said:
Click to expand...


there is a gear inside the transmission that spins the speedo gear. the speedo gear can be replaced from outside but the drive gear is inside on the mainshaft.
 

Pokageek

Active Member
Jun 10, 2005
2,767
0
46
MA, USA
Nov 24, 2006
#6
  • Nov 24, 2006
  • #6
legalize420 said:
there is a gear inside the transmission that spins the speedo gear. the speedo gear can be replaced from outside but the drive gear is inside on the mainshaft.
Click to expand...

Yep. closest I could get mine was it says 10 mph more than what I am doing. Keeps me from speeding nayway. I am going to wait to open up the trans until I get a new trans, lol.
 

Bosko5.0

Active Member
May 18, 2006
1,067
0
37
longwood, FL
Nov 25, 2006
#7
  • Nov 25, 2006
  • #7
+1 on the speedcal

try ebay for a speedcal i bought myne for $50

install is quick and easy, accurate within .02% of speed and you can change it if you have bigger or smaller tires

also looking around i found that the 3.55 and up use the same speedo gear which would be inaccurate
 

SeventyMach1

Keep it lubed .... keep it straight .... and keep
Mar 30, 2005
1,940
3
36
North Carolina
Nov 25, 2006
#8
  • Nov 25, 2006
  • #8
legalize420 said:
there is a gear inside the transmission that spins the speedo gear. the speedo gear can be replaced from outside but the drive gear is inside on the mainshaft.
Click to expand...



Agreed .... but most people never mention that. You can get pretty close without going that far. To be dead accurate, you do have to do that ..... or go SpeedCal.
 
J

jonnystang

New Member
Oct 31, 2006
14
0
0
Littleton, CO
Nov 26, 2006
#9
  • Nov 26, 2006
  • #9
I thought the speedcal was for obdII cars?
 

silverstangman

New Member
Mar 26, 2003
413
0
0
Eastern NC
Nov 27, 2006
#10
  • Nov 27, 2006
  • #10
i forget what tooth i used on mine, i believe it was the one recommended for 3.73's as they had that or one for 4.10's, and even with that in it was still off by 4-5 mph.
 
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