Speedometer help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

demok83 · 06-02-2013, 12:21 AM

Hey guys,

My speedometer has never worked since I purchased my truck. I replaced the speedometer cable today, and it still doesn't work. I hooked the cable up to my drill, and I got the speedometer to read, so I know that cable and speedometer itself is good. I then disconnected the gear housing? (don't exactly know what this thing is called, pic below) from the transmission. It had a little rod that when I turned it, the other side span so I figure that is ok too. I then pulled the little plastic gear out of the transmission and it appears to be in good shape as well. Long story short, everything looked as if it should work! But it doesn't..... Any help? I did just put 20's on it, so I know when I do get it working, it won't be entirely accurate. Any help on that as well? Thanks!

GM-power · 06-02-2013, 12:24 AM

What tranny are you runnin?
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demok83 · 06-02-2013, 12:33 AM

I believe it is the 400

wraprail · 06-02-2013, 12:47 AM

That thing in the picture is a gear reduction (advance) can't remember the exact name but it is used to calibrate the speedo. pull it apart and make sure nothing is messed up inside it. I awalys packed them with grease. Used one for many years.
Thats where I would start.

Also check that your cable is long enough. It has to reach into the speedo and into that reducer.
When you remove the reducer from the trans it has a little metal deal that sticks into the plastic gear in the trans. Make sure its there.

demok83 · 06-02-2013, 09:59 PM

I spun the little rod that stuck out on one side( the side that goes into the tranny) and the other side was spinning as well, so I assumes it was working properly. I can take it apart though and give but a look. Any other suggestions?????
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**hatzie** · 06-02-2013, 10:38 PM

You've narrowed it down to the connection at the transmission/transfer case end.

The driven gear may have a sleeve inside that engages the stub from the gear reduction box.
The same type of sleeve may be required at the reduction box output to mate it to the cable.

These sleeves go missing when the cable or ratio box is unscrewed.

demok83 · 06-02-2013, 11:23 PM

Sorry, I just realized I didn't put the year and model! It is a 1986 custom deluxe. Thank you for the advice. Do they sell these sleeves? I will try to crack into it again tomorrow....

**hatzie** · 06-07-2013, 10:08 PM

Quote:

Originally Posted by demok83

Sorry, I just realized I didn't put the year and model! It is a 1986 custom deluxe. Thank you for the advice. Do they sell these sleeves? I will try to crack into it again tomorrow....

I'm not sure... I'd call a speedometer shop and ask them about small parts like these cable adapter sleeves.

wraprail · 06-08-2013, 09:54 AM

Only other thing it could be is the drive gear inside the trans?
You said the driven gear in the trans is good.
I would just remove the gear reduction/ratio adapter for now untill you actually get the speedo working. One less thing to worry about.

demok83 · 06-08-2013, 05:50 PM

Yes, it was the inside gear! Had the transmission shop put a new one in it, and now I'm good to go. Thanks for the help guys.
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06-02-2013, 12:21 AM	#1
demok83 Registered User Join Date: May 2013 Location: East Texas Posts: 40	Speedometer help Hey guys, My speedometer has never worked since I purchased my truck. I replaced the speedometer cable today, and it still doesn't work. I hooked the cable up to my drill, and I got the speedometer to read, so I know that cable and speedometer itself is good. I then disconnected the gear housing? (don't exactly know what this thing is called, pic below) from the transmission. It had a little rod that when I turned it, the other side span so I figure that is ok too. I then pulled the little plastic gear out of the transmission and it appears to be in good shape as well. Long story short, everything looked as if it should work! But it doesn't..... Any help? I did just put 20's on it, so I know when I do get it working, it won't be entirely accurate. Any help on that as well? Thanks! Attached Images

06-02-2013, 12:24 AM	#2
GM-power Registered User Join Date: Mar 2012 Location: Little Rock, Arkansas Posts: 770	Re: Speedometer help What tranny are you runnin? Posted via Mobile Device __________________ 1979 Sierra Classic Heavy-half 1996 Silverado x-cab "the daily"

06-02-2013, 12:33 AM	#3
demok83 Registered User Join Date: May 2013 Location: East Texas Posts: 40	Re: Speedometer help I believe it is the 400

06-02-2013, 12:47 AM	#4
wraprail Registered User Join Date: Sep 2010 Location: Lake Havasu City Arizona Posts: 863	Re: Speedometer help That thing in the picture is a gear reduction (advance) can't remember the exact name but it is used to calibrate the speedo. pull it apart and make sure nothing is messed up inside it. I awalys packed them with grease. Used one for many years. Thats where I would start. Also check that your cable is long enough. It has to reach into the speedo and into that reducer. When you remove the reducer from the trans it has a little metal deal that sticks into the plastic gear in the trans. Make sure its there. __________________

06-02-2013, 09:59 PM	#5
demok83 Registered User Join Date: May 2013 Location: East Texas Posts: 40	Re: Speedometer help I spun the little rod that stuck out on one side( the side that goes into the tranny) and the other side was spinning as well, so I assumes it was working properly. I can take it apart though and give but a look. Any other suggestions????? Posted via Mobile Device

06-02-2013, 10:38 PM	#6
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: Speedometer help You've narrowed it down to the connection at the transmission/transfer case end. The driven gear may have a sleeve inside that engages the stub from the gear reduction box. The same type of sleeve may be required at the reduction box output to mate it to the cable. These sleeves go missing when the cable or ratio box is unscrewed. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

06-02-2013, 11:23 PM	#7
demok83 Registered User Join Date: May 2013 Location: East Texas Posts: 40	Re: Speedometer help Sorry, I just realized I didn't put the year and model! It is a 1986 custom deluxe. Thank you for the advice. Do they sell these sleeves? I will try to crack into it again tomorrow....

06-08-2013, 09:54 AM	#9
wraprail Registered User Join Date: Sep 2010 Location: Lake Havasu City Arizona Posts: 863	Re: Speedometer help Only other thing it could be is the drive gear inside the trans? You said the driven gear in the trans is good. I would just remove the gear reduction/ratio adapter for now untill you actually get the speedo working. One less thing to worry about. __________________

06-08-2013, 05:50 PM	#10
demok83 Registered User Join Date: May 2013 Location: East Texas Posts: 40	Re: Speedometer help Yes, it was the inside gear! Had the transmission shop put a new one in it, and now I'm good to go. Thanks for the help guys. Posted via Mobile Device



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