23 speedo gear for T45 no go?

Makoto

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Hey guys so of course AFTER i order and install the 23 tooth speedo gear for my T45 that has 4.10 gears I find out they'll apparently be wrecked after a few feet of driving.
Funny thing is, I pulled out a well worn 23 tooth gear from the trans. This might validate the claim somewhat but it was stil working to some extent.

So here's my question, Should I get some other tooth set and just have the tuner set the car up for that digitally or are people actually running these even though they wear out way sooner?

gears1.jpggears3.jpg
gears2.jpg
 

apsmith49921

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I was told the only thing you can do is the Dallas mustang speed cal. I'm in the same boat and I'm just gonna roll the dice on a 23 tooth gear
 

ttocs

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or hit the easy button and mount the phone to the dash and use a app that gives real time speed. I wonder if you could us an old non-active phone?
 

apsmith49921

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Might have been on this site I'm pretty sure but didn't someone have a GPS speedo worked out for sn95 cars? Something about calibrate once and you can even unplug the module?
 

ttocs

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maybe yer thinkin about us holley dudes with the digital dash and gps speedo? Or when white recently got a programmable gas gauge? I am not sure how you would go from gps to stock
 

tsemmett

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There are a couple of ways to correct this. Your current setup definitely will not support 4.10s, but it is possible to change the drive gear in a T45 (GTs run an 8 tooth gear, but Cobras run a 7 tooth, and I believe a 6 tooth T5 gear might also fit), which would require fewer teeth on the driven gear. You could also run a speed cal; Dallas Mustang no longer makes a Mustang specific one, but these cars use an 8k pulse per mile signal, which is fairly common. Dakota Digital's speedo interface can do this. Dakota Digital also makes a GPS sender that claims it can output a 8k ppm signal. That one I have not heard from anyone that has tried it, and it is more expensive ($200 base + an external antenna if you want it to be reliable).

Personally, given that we already have a source of speed output, I don't see me using a GPS unit, but I get the draw.
 

Wmac

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If the 7 & 8 tooth drive gears fit a T45 output shaft, wonder if a 6 tooth would also fit? If so, then a 20 tooth drive gear would be accurate for 4.10 gears.

All 23 tooth gears are aftermarket and made from a much "softer" material than the oem gears.
 

joemomma

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My 23-tooth didn't last long, maybe a drive or two before it started acting wonky again. It's now pretty much shot after maybe 1k miles.
 

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