Speedo problem
Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
So I've done some research. Here is a formula to figure out what speedo gear you need.
(correct speed/indicated speed)current speedo teeth = needed speedo teeth.
I used this calculator to determine indicatied speed and actual speed. I basically did a before and after one on each side of the sheet.
Gear Ratio Calculator
Using 2500 rpms as a baseline I figured out indicated speed and actual. I also removed and counted the teeth on my speedo gear. (20T)
(65mph/55mph) x 20 = 23.6
So I'll round up to 24 as I will only go bigger on tire size not smaller.
Anybody know where I can get the gear?
(correct speed/indicated speed)current speedo teeth = needed speedo teeth.
I used this calculator to determine indicatied speed and actual speed. I basically did a before and after one on each side of the sheet.
Gear Ratio Calculator
Using 2500 rpms as a baseline I figured out indicated speed and actual. I also removed and counted the teeth on my speedo gear. (20T)
(65mph/55mph) x 20 = 23.6
So I'll round up to 24 as I will only go bigger on tire size not smaller.
Anybody know where I can get the gear?
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Posting Guru
Joined: Jun 2004
Posts: 1,092
Likes: 2
From: Casa Grande
There isn't a 24 tooth gear available, 23 is the biggest. And the 23 has a reputation of not lasting very long. What you'll have to do is replace the drive gear or use a ratio correcter.
Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
The drive gear on the transmission shaft? With what? How do I determine which of those?
The current one is yellow.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
E1TZ-17285-A .. Yellow DRIVE gear / 8 teeth, run this-away ////
Nylon DRIVEN gears: 16 thru 21 teeth available. Same gears have been used since 1960, all available from Ford.
LeBaron: No, not yet.
Nylon DRIVEN gears: 16 thru 21 teeth available. Same gears have been used since 1960, all available from Ford.
LeBaron: No, not yet.
Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
So then what do I need to do if i want to get my speedo accurate?
Thread Starter
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Posting Guru
Joined: Jun 2004
Posts: 1,092
Likes: 2
From: Casa Grande
You need to swap in a 9 tooth if your speedo is slower than your going. Mine had a 9 tooth and was reading to fast so had to order an 8 tooth. If you read post #13, I think that's the one, NumbersDummy gave me a few places that carry the gears. And I think he just posted that Ford still carried them also. Just make sure you get the one like you have. Some go //// and some \\\ and ND said yours is this way ///.
Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
You need to swap in a 9 tooth if your speedo is slower than your going. Mine had a 9 tooth and was reading to fast so had to order an 8 tooth. If you read post #13, I think that's the one, NumbersDummy gave me a few places that carry the gears. And I think he just posted that Ford still carried them also. Just make sure you get the one like you have. Some go //// and some \\\ and ND said yours is this way ///.
Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
Well I ended up getting this link from another board. These guys were really helpful and knew exactly what I needed. Quick phone call took care of it.
Speedometer Gear, Speedometer Gears, Ford, GM, Dodge 700R4
Speedometer Gear, Speedometer Gears, Ford, GM, Dodge 700R4
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Senior User
Joined: Sep 2011
Posts: 442
Likes: 1
From: Roanoke, VA
Well I did my calculation backwards. Also my drive gear is in fact 7 teeth.
So all I needed was a 17t driven not a 23t like I thought. Glad I called those guys. When we get the tranny back together I'll report back for closure.
So all I needed was a 17t driven not a 23t like I thought. Glad I called those guys. When we get the tranny back together I'll report back for closure.
Junior User
Joined: Mar 2013
Posts: 67
Likes: 0
From: Olympia, WA
FTE Legend
Joined: Jul 2010
Posts: 32,875
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From: Northeast, OK
This is an easy one. There is a small bolt holding a piece of metal with a semi-circular cutout on the end of it. That cutout is over the end of the cable holding it in the tranny. Pull the bolt and the holder, and then pull gently on the cable. You might have to wiggle it a bit to get it to come, but it will slide right out. The gear is held on the end of the cable with a clip. Be sure and lube the o-ring when you put it together.
Junior User
Joined: Mar 2013
Posts: 67
Likes: 0
From: Olympia, WA
[QUOTE=Gary Lewis;13374859]This is an easy one. There is a small bolt holding a piece of metal with a semi-circular cutout on the end of it. That cutout is over the end of the cable holding it in the tranny. Pull the bolt and the holder, and then pull gently on the cable. You might have to wiggle it a bit to get it to come, but it will slide right out. The gear is held on the end of the cable with a clip. Be sure and lube the o-ring when you put it together.[/QUOTE
Thanks, for the quick answer, i've been pretty busy with the family and I probably won't get to it till next week, but I will keep you posted and probably ask more questions.
Thanks, for the quick answer, i've been pretty busy with the family and I probably won't get to it till next week, but I will keep you posted and probably ask more questions.
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