Speedometer Drive Gear
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Laughing Gas
Joined: Dec 2005
Posts: 904
Likes: 115
From: Laurel, MS
Speedometer Drive Gear
Hey guys. I'm new to the forum.
I recently purchased a '61 F-100 with a 292 y-block v8 and 3-speed on the column, and I've been working on getting it in driveable shape.
I noticed that the speedometer wasn't working so I started investigating.
To make a long story short I found that the speedometer drive gear in the tailshaft of the transmission is stripped out. When I stick my finger in the hole where the speedometer cable goes it feels completely slick.
The driven gear, cable, and speedometer are all ok. (I had my wife watch the speedometer to see if it moved while I spun the driven gear by hand.)
So, how do I replace the speedometer drive gear in the tailshaft of the transmission? Also, where is the best place to purchase one?
thanks,
Michael
I recently purchased a '61 F-100 with a 292 y-block v8 and 3-speed on the column, and I've been working on getting it in driveable shape.
I noticed that the speedometer wasn't working so I started investigating.
To make a long story short I found that the speedometer drive gear in the tailshaft of the transmission is stripped out. When I stick my finger in the hole where the speedometer cable goes it feels completely slick.
The driven gear, cable, and speedometer are all ok. (I had my wife watch the speedometer to see if it moved while I spun the driven gear by hand.)
So, how do I replace the speedometer drive gear in the tailshaft of the transmission? Also, where is the best place to purchase one?
thanks,
Michael
Elder User
Joined: Apr 2008
Posts: 619
Likes: 1
From: Montpelier, VA
I had the same thing happen on one of my 4 speed toploaders. I had to remove the tailshaft in order to fix it. The gear turned out to be ok, the retaining clip (if memory serves correctly) was broken which allowed the gear to move on the shaft. You should be able to do it.
Elder User
Joined: Apr 2008
Posts: 619
Likes: 1
From: Montpelier, VA
I had the same thing happen on one of my 4 speed toploaders. I had to remove the tailshaft in order to fix it. The gear turned out to be ok, the retaining clip (if memory serves correctly) was broken which allowed the gear to move on the shaft. You should be able to do it.
Thread Starter
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Laughing Gas
Joined: Dec 2005
Posts: 904
Likes: 115
From: Laurel, MS
Thanks!
I had not considered that possibility, but that would explain why it feels slick...I was wondering how in the world that happened.
I'm thinking I can do this without removing the transmission from the truck... just pull the tailshaft. Is that correct?
I had not considered that possibility, but that would explain why it feels slick...I was wondering how in the world that happened.
I'm thinking I can do this without removing the transmission from the truck... just pull the tailshaft. Is that correct?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
One size does not 'fit all.'
There is more than one DRIVE gear: Could have 6, 7 or 8 teeth. Some teeth run this-away: ///// .. some teeth run that-away: \\\\\
Some are steel, some are nylon, as it depends on the application. There are different inside diameters, as the DRIVE gears are certain years specific.
DRIVE and DRIVEN gears are determined by the series, wheelbase, trans type, rear axle ratio and the tire size, which can be a pain, since the bias-ply tire sizes used 'back then' are different today with radials.
1961 F100 292 3 speed M/T could have a 3.70, 3.89, or 4.11 ratio. Short wheelbase uses a different DRIVE gear than long wheelbase.
The DRIVE gears have stamped ID numbers marked on them.
There is more than one DRIVE gear: Could have 6, 7 or 8 teeth. Some teeth run this-away: ///// .. some teeth run that-away: \\\\\
Some are steel, some are nylon, as it depends on the application. There are different inside diameters, as the DRIVE gears are certain years specific.
DRIVE and DRIVEN gears are determined by the series, wheelbase, trans type, rear axle ratio and the tire size, which can be a pain, since the bias-ply tire sizes used 'back then' are different today with radials.
1961 F100 292 3 speed M/T could have a 3.70, 3.89, or 4.11 ratio. Short wheelbase uses a different DRIVE gear than long wheelbase.
The DRIVE gears have stamped ID numbers marked on them.
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Elder User
Joined: Apr 2008
Posts: 619
Likes: 1
From: Montpelier, VA
On my toploader, there was also a ball bearing that sits "halfway" into the shaft and fits into a corresponding groove on the drive gear. The retaining clip keeps everthing in place. I was lucky in that i found the ball bearing thingy in the tailshaft when i took it off.
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New User
Joined: Mar 2008
Posts: 1
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I have a 1963 unibody and a similar problem with the cable on the manual transmission. Does anyone know what to look for. I see the top of a plastic gear in the hold but no place to put the end of the speedometer cable. Help! Ken Barnes at kenbarnes54@gmail.com.
New User
Joined: Aug 2019
Posts: 1
Likes: 0
I see this thread doesn't solve the question.
My 63 unibody is a 3 on the tree.
LMC have 6 different types of speedometer drive.
Can anyone point me in the direction for how to determine which one will be correct.
Is there an easy/obvious way to to tell?
My 63 unibody is a 3 on the tree.
LMC have 6 different types of speedometer drive.
Can anyone point me in the direction for how to determine which one will be correct.
Is there an easy/obvious way to to tell?
Lead Gopher
Joined: Aug 2012
Posts: 10,014
Likes: 1,565
From: Seattle
There are a few things that factor into speedo gear selection
Year
Rear Axle Ratio
Transmission
Tire Size
All of the gears in the MPC assume bias ply tires, but most everyone runs radials these days so you have to also do a tongue in cheek estimate as to the bias ply size equivalent of radials. So, there is a little guess work to it even after you nail down some specifics.
Year
Rear Axle Ratio
Transmission
Tire Size
All of the gears in the MPC assume bias ply tires, but most everyone runs radials these days so you have to also do a tongue in cheek estimate as to the bias ply size equivalent of radials. So, there is a little guess work to it even after you nail down some specifics.
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