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

Darthbaker · 03-02-2016, 12:06 PM

I've looked and looked and I can't information on the adapter I need.

I have a 1971 C10, 355, with a 85ish 700R4 transmission. when I bought the truck the previous owner stated I needed a mechanical adapter for the transmission to make the factory cluster speedo to work.

I don't have a pic of the current connection on the transmission at this time but there's a plastic plug adapter on it where i appears to be electronic.

Any advice on where I can get this? A part number? anything....

davepl · 03-02-2016, 02:34 PM

Why do you need an adapter? On my 200-4R of the same vintage (mid 80s) I needed to extend it by 12" but it screwed right in.

What does the trans have that doesn't match you cable? Not a lot of info to go on here...

**dutchmanz** · 03-02-2016, 02:47 PM

http://www.bowtieoverdrives.com/cata....php?ITEMID=19

This is what you need. Probably best to call them to get the correct gears so the speedometer will be accurate. You can also pull this from a used trans in the salvage yard. Your 700r4 is probably newer than 85. The model number is etched into the bottom pan rail and will ID the year.

Davidf · 03-02-2016, 02:48 PM

Simple as removing the electric/electronic speedometer drive and replacing with mechanical.

Darthbaker · 03-02-2016, 04:17 PM

Thanks guys, i'm going to get the look at the Id tag on trans this evening to confirm the year. Thank you for the info.

03-02-2016, 12:06 PM	#1
Darthbaker Registered User Join Date: Dec 2015 Location: Southland Posts: 73	Speedometer Adapter I've looked and looked and I can't information on the adapter I need. I have a 1971 C10, 355, with a 85ish 700R4 transmission. when I bought the truck the previous owner stated I needed a mechanical adapter for the transmission to make the factory cluster speedo to work. I don't have a pic of the current connection on the transmission at this time but there's a plastic plug adapter on it where i appears to be electronic. Any advice on where I can get this? A part number? anything....

03-02-2016, 02:34 PM	#2
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: Speedometer Adapter Why do you need an adapter? On my 200-4R of the same vintage (mid 80s) I needed to extend it by 12" but it screwed right in. What does the trans have that doesn't match you cable? Not a lot of info to go on here... __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

03-02-2016, 02:47 PM	#3
dutchmanz Knuckle Buster, Instructor Join Date: May 2010 Location: Pantego, NC Posts: 562	Re: Speedometer Adapter http://www.bowtieoverdrives.com/cata....php?ITEMID=19 This is what you need. Probably best to call them to get the correct gears so the speedometer will be accurate. You can also pull this from a used trans in the salvage yard. Your 700r4 is probably newer than 85. The model number is etched into the bottom pan rail and will ID the year. __________________ Current classic fleet: 72 K5 Blazer CST, unrestored factory Orange paint...mostly 69 C10 factory SWB, 454, TH400, Saddle tan, Rust-o-ration 53 Studebaker M35 w/331 Reo gas I-6, Air Force Strata Blue

03-02-2016, 02:48 PM	#4
Davidf Registered User Join Date: Nov 2014 Location: Austin Posts: 749	Re: Speedometer Adapter Simple as removing the electric/electronic speedometer drive and replacing with mechanical.

03-02-2016, 04:17 PM	#5
Darthbaker Registered User Join Date: Dec 2015 Location: Southland Posts: 73	Re: Speedometer Adapter Thanks guys, i'm going to get the look at the Id tag on trans this evening to confirm the year. Thank you for the info.

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