Speedo issue

[MidnightBlk98GT]

Does anyone know what the correct color and tooth count is required for the speedo gear that fits a '98 t-45 with 3.73's?

 

[tjm73]

With stock size tires you would need a 24 tooth speedo gear. But no one makes it one. So 23 is as close as you can get.

But don't dispair, if absolute accuracy is what you want, you can get a Dallas Mustagn Speed-Cal speedo correcter for like $100 and it's infinitly adjustable without needing a different speedo gear other than what you already have in the car.

 

[Chili]

Or buy a hand held tuner (like the Predator or Xcal) which can adjust for gear changes, tire size, etc.. Plus you get the other benefits such as tuning (duh), mil eliminators, shift point and pressure adjustments (auto), data logging, diagnostic code reading, etc.. Well worth the $350..

 

[squares98]

Or buy a hand held tuner (like the Predator or Xcal) which can adjust for gear changes, tire size, etc.. Plus you get the other benefits such as tuning (duh), mil eliminators, shift point and pressure adjustments (auto), data logging, diagnostic code reading, etc.. Well worth the $350..

98's have a mechanical speedo, the only options are a gear or a speed-cal. And like tmj said, you need a 23t gear.

 

[MidnightBlk98GT]

Well, the reason I ask is that I had my gears put in about 3 years ago and when it came time to rebuild the tranny the 23 tooth (white) gear that was in there was all chewed up. I bought a replacement gear but now I'm wondering if the feeding gear, the speedometer drive gear, is the correct one that is in there. Any ideas??


Edit: Yes, the speedo sending unit rotates freely.

 

[Chili]

98's have a mechanical speedo, the only options are a gear or a speed-cal. And like tmj said, you need a 23t gear.

Okay.. So I'm an idiot I didn't pay attention to the year.

 

[tjm73]

Well, the reason I ask is that I had my gears put in about 3 years ago and when it came time to rebuild the tranny the 23 tooth (white) gear that was in there was all chewed up. I bought a replacement gear but now I'm wondering if the feeding gear, the speedometer drive gear, is the correct one that is in there. Any ideas??


Edit: Yes, the speedo sending unit rotates freely.

It has been widley reported in the 5.0 end of the Mustang world that the 23 tooth speedo gear has roughly a 20,000-25,000 mile lifespan. They wear out quite a it faster than the other gears with fewer teeth.

 

[jamez1502]

i have 4.10s and mine is 10mph off

 

[tjm73]

i have 4.10s and mine is 10mph off

You need this. Speed Cal

 

[97gtblue]

i have 4.10's and the new speed gear thing and its still off 10mph

 

[tjm73]

i have 4.10's and the new speed gear thing and its still off 10mph

Speed gear thing? Are talkling about the 23 tooth gear?

 

[97gtblue]

couldnt tell you.. ..its some kind of gear that went in my transmission

 

[tjm73]

couldnt tell you.. ..its some kind of gear that went in my transmission

OK. Without going into a long disertation about what and why, the 23 tooth gear is as close as you can get, mechanically, to make your speedo correct. The Speed-cal will make it correct electronically.

 

[9646gt]

my car has 4.10's (96gt) but the speedo sometimes wont work till you hit 80 and sometimes is way off (20+mph) and is never the same..do I have a broken speedo gear? If yes how hard are these to change and what do they cost...I have 275 40's in the rear

 

[tjm73]

my car has 4.10's (96gt) but the speedo sometimes wont work till you hit 80 and sometimes is way off (20+mph) and is never the same..do I have a broken speedo gear? If yes how hard are these to change and what do they cost...I have 275 40's in the rear

That could be an electrical problem, or a wornout needle spring, or something else. Speedo gears are cheap at about $15 bucks or so and are pretty easy to change. I doubt that's the cause baised on what you describe. I'd look for an electrical problem.

275/40R17 is the same height as the stock 245/45R17.

 

[9646gt]

That could be an electrical problem, or a wornout needle spring, or something else. Speedo gears are cheap at about $15 bucks or so and are pretty easy to change. I doubt that's the cause baised on what you describe. I'd look for an electrical problem.

275/40R17 is the same height as the stock 245/45R17.

Great I love electrical problems..but if its a mechanical gauge what type of electrical problem could I have?

 

[tjm73]

Great I love electrical problems..but if its a mechanical gauge what type of electrical problem could I have?

Starting in 1994 Mustangs got electrical guages. The output from the tranny is mechanical, but it goes to a box that converts it to an electrical signal that the dash uses to display your speed.

Unless you have installed a true mechanical speedo.....