Speedometer cable and gears
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FTE Chapter Leader
Joined: Dec 2001
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From: Crossville, Tn
Speedometer cable and gears
I have to pull my speedo cable a few times a year and grease it (I use white Lithium) because it tends to go whacky every few months. While considering installing a new cable, I wondered if the casing shouldn't also be replaced. When researching the cables and casings I ran across the various gears and was surprised to find the numbers for the gears for the 8R19 tires I have. One thing I am unsure of and can't find an explanation is which is the drive gear and which is the driven gear?
I'm thinking the drive gear is the one in the transmission and the driven gear is the one in the speedo. If I'm correct, it is the speedo one that I need to replace, if so does anyone know what is entailed in changing the gear?
I'm thinking the drive gear is the one in the transmission and the driven gear is the one in the speedo. If I'm correct, it is the speedo one that I need to replace, if so does anyone know what is entailed in changing the gear?
Fleet Mechanic
Joined: Aug 2010
Posts: 1,994
Likes: 3
From: Morgan Hill, CA
Hi Joe,
What transmission are you using? In the Ford automatic transmissions, the driven gear is the plastic gear at the end of the speedo cable that goes into the transmission. It is changed by pulling out one snap ring and slipping the gear off of the cable.
I'm not how to change the gear in the manual tranmissions.
Is your speedo inaccurate? I found an iphone app called JustSpeed that provides a pretty accurate GPS speed reading...I plan on using that to see if I picked the right speedo gear for my rear end ratio and tire size.
Dan
What transmission are you using? In the Ford automatic transmissions, the driven gear is the plastic gear at the end of the speedo cable that goes into the transmission. It is changed by pulling out one snap ring and slipping the gear off of the cable.
I'm not how to change the gear in the manual tranmissions.
Is your speedo inaccurate? I found an iphone app called JustSpeed that provides a pretty accurate GPS speed reading...I plan on using that to see if I picked the right speedo gear for my rear end ratio and tire size.
Dan
Post Fiend
Joined: Jun 2001
Posts: 7,493
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From: Erie, pa
The drive gear is the one one the rear shaft of the tranny (Inside the tail shaft) - The driven gear is the one on the transmission end of the speedo cable - These two gears are paired to the rearend gear ratio and the rear tire size - If your speedo cable casing is original you may want to replace it - They can develop defects that effect the cable.
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FTE Chapter Leader
Joined: Dec 2001
Posts: 3,636
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From: Crossville, Tn
The drive gear is the one one the rear shaft of the tranny (Inside the tail shaft) - The driven gear is the one on the transmission end of the speedo cable - These two gears are paired to the rearend gear ratio and the rear tire size - If your speedo cable casing is original you may want to replace it - They can develop defects that effect the cable.
It doesn't show the 8R19.5 in the original manual, but on the parts CD it list the 8R19.5 as the same as the 7.00x18. I found a couple of sources that have the driven gears along with the cable and casing.
Just wondered how big of a job it is to change that driven gear?
Old Dan, I have the stock 4 speed spur transmission. no automatics available on the F5 in 1950.
Posting Guru
Joined: Feb 2009
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From: victoria
try useing molly ,,, molybdenum disulfide for locks ..it is finer and won't dryout or collect giunk to mess up the speedo I have it on my harly and my bronco with no problems ..and the only gear you need to change is the one on the cable ..that is why there are choices ..
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