4:10 gears

[hollywoodstang]

i just got new transmission put in and FMS auburn posi and 4:10 gears in.
now my speedo is all jacked up. is this normal?
and is my RPM wrong too>?
i have all other auto meters ready to go in. but i didn't buy the tech. i thought i didn't need it. should i still buy one or does the rpm stays true?
thanks

 

[AznStanger3v]

you need the 23 tooth speedo gear for the transmission. its like 15 bones and you can get it online or at Ford.

 

[The Green GT]

What he said, plus your tach is right, no need to get another.

 

[SVTCobra306]

Fords tach is usually off some. I simply use a shiftlight so I know for sure when to shift. Not a big fan of the huge tachs in street cars... To each his own though..

 

[Stanger007]

I kept my stock gear and used a Dallas Mustang SpeedCal to get the speedo corrected - the closest gear I could find for the 4.10s was still off by 5-10mph depending on how fast I was going.

 

[Blackened302]

i've read those speedcal's DO and DON'T work for 94-95... most sites, including Dallas Mustangs, say they're for 96+...???

 

[Bosko5.0]

they do work for 94-95; stanger007 made a step by step install.

 

[Bosko5.0]

at least i think he did.

 

[Blackened302]

they do work for 94-95; stanger007 made a step by step install.

link?

 

[Stanger007]

Worked great on my car - I'll post the link up in a sec.

 

[Stanger007]

I made some notes on where my install differed from the included instructions (which are great BTW).

http://www.72mach1.com/95-mustang-gt/aode-speedcal-install/

 

[SVTCobra306]

Yeah, they'll work. Our cars have kind of a "hybrid" speedo, partially mechanical, so the speedcal can still fix it, however a speedo gear can also still fix it...

 

[final5-0]

Using the driven gear will not get the speedo on the money.

Heck ... with 373's ... the gear method is off a bit.

With 410's ... you're gonna be a good deal off.

The only way to get accurate with gear changes is to change the drive gear. To do that ... you gotta go into the tailshaft part of the tranny.

The speedcal doo dad does work as many of our members have used them with success.

Grady

 

[Blackened302]

thanks for clearing that up, Grady. i was a bit freaked as i've read that they do and do not work.

 

[final5-0]

We got so many smart peeps here

I hang around and see what they say works

I then just pass it on

Grady

 

[Synned]

Yeah so I got my 4:10's in, and they changed the speedo gear as well, but It's definetally way off. 70mph feels like 85...
So my question is..can I drive next to someone with my gauges exposed (say at 40mph) and adjust the needle?
Will that sync it?

 

[Blackened302]

hmm--i would think that because of tranny and differential gear ratios, the measurement is more exponential than linear, so i would say no, joe.

i could very well be wrong, though, just a gander.

 

[Synned]

hmm--i would think that because of tranny and differential gear ratios, the measurement is more exponential than linear, so i would say no, joe.

i could very well be wrong, though, just a gander.

no, that makes sense now...duh...

 

[Black95GTS]

http://www.brothersperformance.com/catalog/product_info.php/products_id/1327

We need to make this a sticky.