"Jittery" Speedometer Needle
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From: Dixie - Tennessee
"Jittery" Speedometer Needle
Just picked up an '85 F-150 4.9L/4-speed from the local tote'the'note for $400 cash.
Darn 'ol truck runs like a top, ain't beat up or nothing, and doesn't have any rust problems at all (except for some MINOR surface rust beginning, which will be taken care of later).
Anywho, I noticed on the test drive that the speedometer didn't work. Then, on my way home, it starts picking up and jumping around on 15mph when I think I'm doing 30-35mph.
Then, when I'm up to 55-60mph, it jumps around on 45mph.
I bought a "universal" speedometer cable kit before it ever showed signs of even working at all, but now I'm not sure where to begin.
I thought of starting by loosening the bolt that houses the speedo' gear in the transmission and see if there are any loose connections, or what have you, at that point.
I had an '85 F-250 6.9L/C6 that did the same thing, but never dove into it to figure out the problem.
Any insight would be great!
Nightrain
Darn 'ol truck runs like a top, ain't beat up or nothing, and doesn't have any rust problems at all (except for some MINOR surface rust beginning, which will be taken care of later).
Anywho, I noticed on the test drive that the speedometer didn't work. Then, on my way home, it starts picking up and jumping around on 15mph when I think I'm doing 30-35mph.
Then, when I'm up to 55-60mph, it jumps around on 45mph.
I bought a "universal" speedometer cable kit before it ever showed signs of even working at all, but now I'm not sure where to begin.
I thought of starting by loosening the bolt that houses the speedo' gear in the transmission and see if there are any loose connections, or what have you, at that point.
I had an '85 F-250 6.9L/C6 that did the same thing, but never dove into it to figure out the problem.
Any insight would be great!
Nightrain
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Joined: Jul 2004
Posts: 8,786
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From: Northern California
The cable is probably frayed and worn out. Shot etc...
Replacing it is probably the best course of action. Remove the old cable to check for damage etc.. It seperates for the plastic housing you will have to remove the cluster and speedometer cable gear from the cable (held on with a clip) at the other end at the tranny. Should pull right out of it's housing from the inside of the cab.
Make sure you lubricate the new cable with either speedometer cable lubricant Ford Part Number: D2AZ-19581-A / specification ESF-M1C160-A. Or white lithium grease will also work well.
Lubricate the cable every year or so, or any time a slight needle hop is detected.
hope this helps
Replacing it is probably the best course of action. Remove the old cable to check for damage etc.. It seperates for the plastic housing you will have to remove the cluster and speedometer cable gear from the cable (held on with a clip) at the other end at the tranny. Should pull right out of it's housing from the inside of the cab.
Make sure you lubricate the new cable with either speedometer cable lubricant Ford Part Number: D2AZ-19581-A / specification ESF-M1C160-A. Or white lithium grease will also work well.
Lubricate the cable every year or so, or any time a slight needle hop is detected.
hope this helps
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From: Virginia
You can pull the cable loose at the tranny end, and twirl it with your fingers and see how freely it turns. You can also do this while someone is watching the needle in the cab.
If you put a new cable on, and it still does it, then the old cable may have ruined the plastic gear that goes up in the tranny housing.
If you put a new cable on, and it still does it, then the old cable may have ruined the plastic gear that goes up in the tranny housing.
Elder User
Joined: Mar 2004
Posts: 517
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From: Texas
Originally Posted by Franklin2
You can pull the cable loose at the tranny end, and twirl it with your fingers and see how freely it turns. You can also do this while someone is watching the needle in the cab.
If you put a new cable on, and it still does it, then the old cable may have ruined the plastic gear that goes up in the tranny housing.
If you put a new cable on, and it still does it, then the old cable may have ruined the plastic gear that goes up in the tranny housing.
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From: Dixie - Tennessee
Thanks, ya'll.
I was thinking at first that something had come loose, but when it started working on the way home, I didn't know where to start.
I am going to replace the cable with the kit I bought today and see what happens.
But, if it still does it with the new cable, replace the plastic gear in the trans, right?
Thanks again!
Nightrain
I was thinking at first that something had come loose, but when it started working on the way home, I didn't know where to start.
I am going to replace the cable with the kit I bought today and see what happens.
But, if it still does it with the new cable, replace the plastic gear in the trans, right?
Thanks again!
Nightrain
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From: Dixie - Tennessee
Welp, I seem to be stumped again...
I pulled the cable and drive gear out of the transmission and spun it with my fingers while the wifey-to-be watched the needle. It moves. The cable also spins freely.
But, when inserted back into the transmission and given a little test drive down the road, I still have nothing 'till about 55mph or so, where the needle begins to jump between 35-45mph.
I pulled the cluster out before that, and the cable has a firm connection with the speedometer itself.
Also, the gear doesn't look to be worn out. I still haven't replaced the cable, but plan on doing so once I get some sleep. Whether or not it needs it at this point is unclear, but it is "fix-it-before-it-fails" maintenance.
Thanks for all of the help, ya'll...
Nightrain
I pulled the cable and drive gear out of the transmission and spun it with my fingers while the wifey-to-be watched the needle. It moves. The cable also spins freely.
But, when inserted back into the transmission and given a little test drive down the road, I still have nothing 'till about 55mph or so, where the needle begins to jump between 35-45mph.
I pulled the cluster out before that, and the cable has a firm connection with the speedometer itself.
Also, the gear doesn't look to be worn out. I still haven't replaced the cable, but plan on doing so once I get some sleep. Whether or not it needs it at this point is unclear, but it is "fix-it-before-it-fails" maintenance.
Thanks for all of the help, ya'll...
Nightrain
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Post Fiend
Joined: Jul 2004
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From: Northern California
It could be the speedometer head itself too.
Does the odometer work even when the needle isnt moving?
=======
Edit: Just reread your post.
It seems to be the plastic gear inside the transmission is probably at fault.
There are two gears one at the end of the cable that sticks into the transmission, and the other gear this one mates to inside the transmission itself.
The gear inside the tranny is not easy to replace either.
Does the odometer work even when the needle isnt moving?
=======
Edit: Just reread your post.
It seems to be the plastic gear inside the transmission is probably at fault.
There are two gears one at the end of the cable that sticks into the transmission, and the other gear this one mates to inside the transmission itself.
The gear inside the tranny is not easy to replace either.
Last edited by 81-F-150-Explorer; Feb 28, 2007 at 03:00 PM.
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Thread Starter
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Posting Guru
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From: Dixie - Tennessee
I haven't paid any attention to the odometer, but I'll check it and see next time I'm out and about.
When I check it, I'll let ya'll know what prevails.
Thanks again.
Nightrain
When I check it, I'll let ya'll know what prevails.
Thanks again.
Nightrain
Last edited by Nightrain; Mar 1, 2007 at 08:43 AM.
New User
Joined: Jan 2007
Posts: 13
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From: REDSKIN COUNTRY
Speedometer Cable............................................. 5.00
This is the price I paid for the used cable from Crazy Rays in Jessup Maryland. Did the replacement in a bout 45 mins to an hour (not in a rush).
http://www.crazyraysautoparts.com/price.htm
84 Ford F-150 4.9L carby, w manual granny gear. All stock but I do have the OEM clock...woohoo!
This is the price I paid for the used cable from Crazy Rays in Jessup Maryland. Did the replacement in a bout 45 mins to an hour (not in a rush).
http://www.crazyraysautoparts.com/price.htm
84 Ford F-150 4.9L carby, w manual granny gear. All stock but I do have the OEM clock...woohoo!
Posting Guru
Joined: Jun 2004
Posts: 1,635
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From: Niceville, FL.
Clean and lube the cable and housing (both sections if you have speed control). I use lithium or molybdenum disulfide based lube or white marine grease. Getting all the old hardened grease out seems to make a big difference.
Cargo Master
Joined: Apr 2003
Posts: 2,057
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From: Too close to Houston
Do you have cruise control? If so, you may have 2 cores in your speedometer cable. Separate it at the CC pickup coil to check the short length that runs to the speedometer head.
The driven gear gear will probably look like one of these:
They can break, strip, or were sometimes trimmed by previous owners in order to drive without running up the odometer. Replacements aren't hard to find and they are color-coded for tooth count.
Speedometer World
The driven gear gear will probably look like one of these:
They can break, strip, or were sometimes trimmed by previous owners in order to drive without running up the odometer. Replacements aren't hard to find and they are color-coded for tooth count.
Speedometer World
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From: Dixie - Tennessee
Mine is white. Looks like the tooths are in good shape, though. (Don't make fun of me; I'm from the South). :-x22
I'm going to start with the cable and move on from there, as needed.
BTW, the 'ol rig don't have cruise control. She's standard and stripped-down all the way...
Thanks again.
Nightrain
I'm going to start with the cable and move on from there, as needed.
BTW, the 'ol rig don't have cruise control. She's standard and stripped-down all the way...
Thanks again.
Nightrain
Last edited by Nightrain; Mar 4, 2007 at 12:03 PM.
