mph issue?????/

[blue5.8]

i just bought a car that i was told had a 410 gear speedo in it but it has stock gears the spedometer reads about 12mph lower than actual speed would this be the issue or could it be something else.

[Kevin1989]

Yes mine was 10mph fast with a 3.73.

[blue5.8]

with out a gear in the rear end?

[adragon72]

i have a 93 gt with 373 gears in the rear end and i run a white trans speedo gear and mine is dead on. i put 410s in my wifes 95 and a whit speedo gear and it reads about 10 mph low. the t5 is the same on both cars because i pulled the trans from mine and put in her car. you can purchase speedo gears for the trans to correct your speedo. now i just have to figure out witch one i need for her car.

cincy speed has some of the gears in stock and most speed shops can get them for you, i think S&M might have some also.

[blue5.8]

so you think it has the gear in the rear end but not the speeddo gear?

[chris91]

In order to get the correct speedo gear you need to know what gear is in the rear end. Easiest way to tell what gear it is, is put the rear on stands. Mark the wheel and mark the driveshaft. Have someone spin the wheel 10 times while someone is counting how many times the driveshaft spins. If it spins 37-38 times you have 3.73. Spins 41-42 times 4.10, etc.

[blue5.8]

sweet thanks chris

[Kevin1989]

I thought if you turned the tire once and counted the drive shaft it would tell you

[jktruckin06]

He told him correct, just 10 times the work lol. One spin will get you close.

[Blackout]

sounds like it has chip or 4.10 speed sensor gear that is messing with it.

[NXcoupe]

i just bought a car that i was told had a 410 gear speedo in it but it has stock gears the spedometer reads about 12mph lower than actual speed would this be the issue or could it be something else.

That's correct. The more teeth the speedo gear has on it, the slower it spins the speedometer cable, the slower the speedo reads. A smaller tooth count gear will make the speedo read faster. So it probably has the wrong gear in it, something for a steeper gear in it. Pull the gear out and count the teeth on it, the speedo gear that is.

[red srides]

4 banger trany maybe

[1baddlx]

I always pull the tranny and install a 6 tooth gear in the tranny,then that way if you go up in rearend gear then u can buy a Ford speedo gear,the white ones (21 or 23 tooth from steeda ) always chew teeth up in time due to the teeth being thin.actually I'm doing one now lol.it seems every tranny I get has 8 tooth in it .arrrrgh.