I am going to change my speedo gear to match the 3.73 gears in my car. My question is, do I have to put grease or anything on the new gear, or do I just swap out old for new? I'm talking about the one at the transmission. Thanks for any help.
speedo gear change ?
- Thread starter sonicblustreak
- Start date
You have to change the one on the tranny too? i am swaping to 3.55. i thought you only had to switch the one on the end of the cable.
I believe its at the end of the cable, where it goes in the side of the trans.
Thanks!!
if you have 3.73s i believe you do or it will still be off. if you have 3.55s you would just change the one on the speedo cable.
If using 3.73, what tooth is correct?
anything 3.73s or lower you will have to change the speedo gear, and additionally you will need to change the drive gear in the T5. most (mustang GT/LX) folks dont care enough to mention this, but SVT owners should be more particular because if you dont do this then you will rack up more miles on your 15k mile cobra than were actually driven!
see steps 7-8.. bottom of the page :beer:
T5 Transmission Rebuild - G-Force T5 - Modern Driveline - FordMuscle.com
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So I have to open up the trans case and change the Speedometer drive gear to correct a 3.73 gear change? That sucks!
No, you don't.
But to RydeOn's point, to be dead nuts accurate, you should. I can tell you that 99% of folks don't, including myself. Another car I had I only switched out the one at the end of the cable and if it was off, it was minimal.....maybe 1 mph.
But to RydeOn's point, to be dead nuts accurate, you should. I can tell you that 99% of folks don't, including myself. Another car I had I only switched out the one at the end of the cable and if it was off, it was minimal.....maybe 1 mph.
Then what tooth gear is going to get me REAL close?
Here you go.......everything you need to know. Like I said, I don't know anyone who has ever changed out the tailshaft gear on a gear swap.
Speedometer Recalibration Gears - '79-'98 Ford Mustang
Speedometer Recalibration Gears - '79-'98 Ford Mustang
Right on.. thanks!
That does not make it correct! Please do not pass misleading information on.
Im trying to recall how exactly how this went, because its been ages since Ive messed mine. But if I remember correctly the stock speedo drive gear is an 8 tooth. We have a black speedo cable gear in our cars, 20 tooth, stock. Look at the chart/parts list and you see that the 23 tooth speedo gear is the maximum they run and they are correct for 3.55s. Notice they are all 23 tooth for 3.55s, 3.73s and 4.10. This is because the gear ratios are too far out of range to be calibrated with the stock 8 tooth drive gear. The chart clearly shows that you need to drop to a 7 tooth to bring any rearend gears 3.73s into correctable range by using the appropriate speedo gear. By using your same black 20 tooth and just changing from an 8 to 7 tooth drive gear your calibration goes from 3.08 to 3.55s. That is a significant difference. Much more than 1mph as was previously mentioned, more like 4-6mph, and thousands of miles extra per years owned.
..And this should be factually correct, if anyone would like to verify please do and correct me if I am wrong. What you do on your car is up to you, but lets base this off of facts rather than what other people are doing with their cars. I have seen too many cobra adds with the text "car says 35k on the odometer but really has under 28k since i reageared". Sure it does bud, "next".
LOL!
Easy dude. If you look at my previous, I basically backed up what you already stated. I'm absoulutley not saying just because nobody does it makes it right........geesh!
As far as your 4-6 mph calculation, your way off. I promise you, with my previous cars, I noticed nothing on the speedo to show that it was anything even close to that and a dyno trip or two to verify it.
And back to N2Fords2003, he asked what would get him "real close" and that's all I provided.....or should I say Steeda provides.
Like everything else on the internet, take it with a grain of salt and call the experts and see what they say. $100 says not a one of them tries to sell you the tailshaft gear to go with the speedo gear when running 3:73's out back! Anything numerically higher than that is when you start to run into speedo's that are way off...10% and higher as you climb the chart.
Easy dude. If you look at my previous, I basically backed up what you already stated. I'm absoulutley not saying just because nobody does it makes it right........geesh!
As far as your 4-6 mph calculation, your way off. I promise you, with my previous cars, I noticed nothing on the speedo to show that it was anything even close to that and a dyno trip or two to verify it.
And back to N2Fords2003, he asked what would get him "real close" and that's all I provided.....or should I say Steeda provides.
Like everything else on the internet, take it with a grain of salt and call the experts and see what they say. $100 says not a one of them tries to sell you the tailshaft gear to go with the speedo gear when running 3:73's out back! Anything numerically higher than that is when you start to run into speedo's that are way off...10% and higher as you climb the chart.
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Here, I'll make this post factual, just so no one is mislead.
To Rydeon's point, he is absolutely correct. To be obtain the best approximated MPH (these things are not %100 but close) you would need to change the tail shaft gear on a 90-95 Mustang t-5 to use the 23 tooth speedo gear. Here's the breakout, per Ford Racing:
8(tailshaft gear)x 3:73 (rear gear)x 815 (Tire rev. Per Mile) = 243196 / 1000 = 24.3196
The last number is the desired gear. As you can see, the numerically highest gear availble is a 23 tooth.
Now, back to my point, which was the 23 tooth is very close and I don't mean the tooth count. I'm talking actual speedometer readings. So let's say it's off 4% which would be barely noticeable by most, inlcuding me. That isn't so much the problem as is the odometer. For every 10k on the you put on the ticker, you'll be short by 400 actual miles.
Now to really fry your mind, all the engineering Ford put into the the plastic gear setup, the tire revelolution per mile formulation is all based on a 25.7" tall tire out back. Any variation from this can change the speedo readings significantly also.
So there it is to the best of my knowledge. Take if for what it's worth, do your research and pick your poison and just call the experts when in doubt.;-)
To Rydeon's point, he is absolutely correct. To be obtain the best approximated MPH (these things are not %100 but close) you would need to change the tail shaft gear on a 90-95 Mustang t-5 to use the 23 tooth speedo gear. Here's the breakout, per Ford Racing:
8(tailshaft gear)x 3:73 (rear gear)x 815 (Tire rev. Per Mile) = 243196 / 1000 = 24.3196
The last number is the desired gear. As you can see, the numerically highest gear availble is a 23 tooth.
Now, back to my point, which was the 23 tooth is very close and I don't mean the tooth count. I'm talking actual speedometer readings. So let's say it's off 4% which would be barely noticeable by most, inlcuding me. That isn't so much the problem as is the odometer. For every 10k on the you put on the ticker, you'll be short by 400 actual miles.
Now to really fry your mind, all the engineering Ford put into the the plastic gear setup, the tire revelolution per mile formulation is all based on a 25.7" tall tire out back. Any variation from this can change the speedo readings significantly also.
So there it is to the best of my knowledge. Take if for what it's worth, do your research and pick your poison and just call the experts when in doubt.;-)
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I got a 23 tooth on the way and I will check it with GPS.. there not expensive so I will get another one if its not good enough. I will report back
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