Speedometer Driven Gear, # of teeth?
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Speedometer Driven Gear, # of teeth?
I have a 1980 F100, 3 speed mt 3 on the tree, 4.9 six cylinder. My speedo driven gear is gone, must have either fallen off inside and/or disintegrated. Here is the only data I have to solve this mystery. Axle ratio is 2.75, tire diameter is 26.52, original tire size is 195/75/15 but I'm running 235/75/15 so my tire diameter is 28.88. The axle code is 13 and tran type is C. I don't know exactly how many teeth the drive gear in the case has. I barely saw it over the shoulder of my mechanic. He thought he counted ~ 5 teeth, but I think he may have missed the leading and ending thread swirls.
With the above said, does anyone know how many teeth the driven gear should have and what the Ford part number is????
Thanks in advance for the help!
With the above said, does anyone know how many teeth the driven gear should have and what the Ford part number is????
Thanks in advance for the help!
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
I have a 1980 F100, 3 speed M/Ton the tree, 4.9L six cylinder. My speedo driven gear is gone, must have either fallen off inside and/or disintegrated. Here is the only data I have to solve this mystery.
Axle ratio is 2.75, tire diameter is 26.52, original tire size is 195/75/15 but I'm running 235/75/15 so my tire diameter is 28.88. The axle code is 13 and tran type is C. I don't know exactly how many teeth the drive gear in the case has. I barely saw it over the shoulder of my mechanic. He thought he counted ~ 5 teeth, but I think he may have missed the leading and ending thread swirls.
With the above said, does anyone know how many teeth the driven gear should have and what the Ford part number is????
You can "look it up" yourself, cuz here is the info.
Axle ratio is 2.75, tire diameter is 26.52, original tire size is 195/75/15 but I'm running 235/75/15 so my tire diameter is 28.88. The axle code is 13 and tran type is C. I don't know exactly how many teeth the drive gear in the case has. I barely saw it over the shoulder of my mechanic. He thought he counted ~ 5 teeth, but I think he may have missed the leading and ending thread swirls.
With the above said, does anyone know how many teeth the driven gear should have and what the Ford part number is????
You can "look it up" yourself, cuz here is the info.
For those unaware: DRIVEN (17271) gear at end of cable, DRIVE (17285) gear on output shaft of tranny. When typing related posts, I always capitalize these gears to define one from the other.
16 thru 21 teeth nylon DRIVEN gears available, same ones have been used since 1960, all are available from FoMoCo for 6 bucks or less.
DRIVEN with 2.75 ratio: Left/Right upper pics / 1980 DRIVE, Left lower pic / L (left) or R (right) after tooth count refers to which way the teeth run).
Notice parts catalog error: F100 missing from DRIVE chart, would be the same as F150. Same part number (E0TZ-17285-A 9L) listed for 1981.
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Cross-Country
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ND,
Thanks SO very much for sharing this knowledge with me, others. After inheriting my late father in 2005, I will finally know (see) how fast I'm going. Days ago I recovered from a column shift lever socket failure. Could not find E0TZ7228 so I bought a D9TZ7228 (Ford OEM part from a local NOS), took it to a machine shop and had ~3/8 inch shaved off top rim and it works exceeding well.
So, getting this gear identified, bought and installed will fix my last mechanical problem for now.
Again, many thanks!
Sincerely,
F100Mann
Thanks SO very much for sharing this knowledge with me, others. After inheriting my late father in 2005, I will finally know (see) how fast I'm going. Days ago I recovered from a column shift lever socket failure. Could not find E0TZ7228 so I bought a D9TZ7228 (Ford OEM part from a local NOS), took it to a machine shop and had ~3/8 inch shaved off top rim and it works exceeding well.
So, getting this gear identified, bought and installed will fix my last mechanical problem for now.
Again, many thanks!
Sincerely,
F100Mann
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I am stumped! Still have not solved my speedo problem. I bought Speedo 'driven' gear CD4Z-17271-A as per the chart previously shared above for my 1980 Ford F100, 3 speed manual tranny and the 'drive' gear in the case is RED and I counted ~7 gear edges, ribs. However, post installation the speedometer moves ever so reluctantly. It is either doesn't clock at all, or it does but not correctly (I'm going 50, its showing 30 mph) and the needle bounces. Then I thought about the cable itself. So, I disconnected both ends, the one at the drive case and the one at the speedo. I spun the drive case end while a friend looked at the speedometer cable end and the core was spinning within the cable housing. If I spun fast or slow, it behaved accordingly. I did not test it with the cable connected to the speedometer (humm?? maybe I should have?)
So, do I have a bad speedometer/odometer or the wrong 'driven' gear? Any words of wisdom?
So, do I have a bad speedometer/odometer or the wrong 'driven' gear? Any words of wisdom?
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Update: I have been on some journey since my original post about my confounding speedometer issues. Today, a friend of mine (a local NOS Ford dealer) and I did an experiment, a bench test of sorts. I removed the speedo cable from the drive case and removed the 'driven' gear (C4DZ-17271-A) from the tip of the speedo cable. He inserted the speedo cable core (tip) into a power drill and spun the drill slowly to higher speeds. Well, there is nothing wrong with the cable or the speedometer as it was responsive. Having eliminated, the speedometer, cable and driven gear, the only thing left is the drive gear in the case (E0TZ-17285-A). Yikes! This means having to get in the drive case, remove and replace the gear. The gear is pressed on the shaft. A local mechanic said he'd do it for $150. I found the drive gear at NOS in Texas for $21. I think I'll continue driving the truck without knowing how fast or far I'm going for a little while longer, but at least I'll have the gear when I'm ret-to-go.
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Update: O.k, here is where I find myself. I ordered the 'drive' gear, but something kept bugging me. The current one looks fine for as much as I can see it in the drive case through the hole the speedo attachs through. To get a full view of what the inside looks like, I found this how to video see below. One thing I noticed as this guy is replacing the drive gear is a retaining clip, which holds the drive gear in place and if this is broken the drive gear will slide along the shaft. This would explain why it works off and on (mostly off). This might be the only problem I have, the failure of a ~$2-$3 part. However, even if it is the sole problem, it would be silly not to replace both while in there. Oh well, keep on trucking!
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I hate seeing a guy using a carpenter's hammer doing automotive work. Makes me wonder how professional (and correct) his advise is.
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