Speedometer Gear Question

6

66StangFastback

New Member

Jun 6, 2005

181

0

0

norman, oklahoma

Jan 7, 2007

#1

• Jan 7, 2007

• #1

I just went from 2.8:1 gears to some 3.55s and have found (using my GPS) the the speedometer is WAY off. I know I need to change the speedometer gear, but don't know what kind to buy or how to change it.

The car has the Ford C4 3 speed auto transmission, and 215/70r14 tires on it, with newly installed 3.55:1 gears.

What speedo gear do I need and how do I put it in?

 

rbohm

Founding Member

Apr 12, 2002

6,698

550

204

tucson,az

Jan 7, 2007

#2

• Jan 7, 2007

• #2

assuming a 7 tooth drive gear, you need a 20 tooth driven gear.

 

S

suki243

Member

Dec 19, 2006

662

0

19

Southern California

Jan 7, 2007

#3

• Jan 7, 2007

• #3

I have a similar problem with my 66, I was on the freeway and i looked at the speedometer and it told me i was goin 70+ but i was at the same speed as a big rig up ahead and everyone was passing me

 

6

66StangFastback

New Member

Jun 6, 2005

181

0

0

norman, oklahoma

Jan 7, 2007

#4

• Jan 7, 2007

• #4

rbohm said:

assuming a 7 tooth drive gear, you need a 20 tooth driven gear.

Click to expand...

How do I find out the number of teeth in my drive gear?

 

S

suki243

Member

Dec 19, 2006

662

0

19

Southern California

Jan 7, 2007

#5

• Jan 7, 2007

• #5

Check this out
http://forums.stangnet.com/showthread.php?t=484151
http://www.tciauto.com/Products/TechInfo/speedo_gears.asp#FORD

 

6

66StangFastback

New Member

Jun 6, 2005

181

0

0

norman, oklahoma

Jan 7, 2007

#6

• Jan 7, 2007

• #6

Thanks suki.

I guess I just need to know the number of teeth on the "drive gear"

 

rbohm

Founding Member

Apr 12, 2002

6,698

550

204

tucson,az

Jan 7, 2007

#7

• Jan 7, 2007

• #7

pull the driven head from the trans, and count the teeth on the shaft. most likely the trans you have will have 7 drive teeth.