What is this used for? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

3K144J · 03-23-2019, 05:05 PM

I am not sure exactly what this is used for, it is on the driveshaft between my SM420 and my T221 Transfer case. Is it for the speedo or overspeed indicator? Looks like it was wired up at one time.... Any help would be appreciated! Thanks!

68Gold/white · 03-23-2019, 05:26 PM

Probably add on cruise control. That piece strapped onto the drive shaft is likely a magnet...
Never seen one that big, though...

TwoFiftyShifter · 03-23-2019, 06:04 PM

Cruise control? Interesting if true.

3K144J · 03-23-2019, 08:45 PM

Thanks 68Gold/White!

**Captainfab** · 03-23-2019, 11:20 PM

Yep, that is for an aftermarket add on cruise control.

**mattfranklin** · 04-03-2019, 10:46 AM

There was a quote attributed to Charles F. "Boss" Kettering, an old time GM engineer: "Parts left off cost nothing and cause no service problems."

Not sure if he really said that but I always loved the quote and try to live by it and keep my projects simple. So snip off that garbage and pretend it was never there. :-)

burnin oil · 04-03-2019, 10:53 PM

Quote:

Originally Posted by mattfranklin

There was a quote attributed to Charles F. "Boss" Kettering, an old time GM engineer: "Parts left off cost nothing and cause no service problems."

Not sure if he really said that but I always loved the quote and try to live by it and keep my projects simple. So snip off that garbage and pretend it was never there. :-)

Or look and see if the rest of the system is still there. I am pretty sure that a Hall effect switch could replace that pickup that isnt wired in.

*YoungPup1977* · 04-09-2019, 10:24 AM

Quote:

Originally Posted by mattfranklin

There was a quote attributed to Charles F. "Boss" Kettering, an old time GM engineer: "Parts left off cost nothing and cause no service problems."

Not sure if he really said that but I always loved the quote and try to live by it and keep my projects simple. So snip off that garbage and pretend it was never there. :-)

I like to fix things and get the cruise control working but again I am not like most people.....just like the dust cover on the trans, why is it always missing ? I am starting to understand...taking me a while but this forum is helping.

68gmsee · 04-10-2019, 04:24 PM

Had one of those add on cruise control things on a 76 van I once owned. Installed it myself and it worked for many years. Used two small magnets glued to the drive shaft opposite each other. I once lost one of the magnets and it still worked, however.

There should be a control unit under the dash somewhere and if it's still there a vacuum control unit on the engine attached to the throttle linkage. The control unit had an adjuster to set the off and on timing of the cruise control to keep it at a constant speed.

03-23-2019, 05:05 PM	#1
3K144J Registered User Join Date: Jun 2018 Location: Meridian, Idaho Posts: 14	What is this used for? I am not sure exactly what this is used for, it is on the driveshaft between my SM420 and my T221 Transfer case. Is it for the speedo or overspeed indicator? Looks like it was wired up at one time.... Any help would be appreciated! Thanks! Attached Images

03-23-2019, 05:26 PM	#2
68Gold/white Registered User Join Date: Sep 2011 Location: Ark City, Kansas Posts: 3,279	Re: What is this used for? Probably add on cruise control. That piece strapped onto the drive shaft is likely a magnet... Never seen one that big, though...

03-23-2019, 06:04 PM	#3
TwoFiftyShifter Registered User Join Date: Nov 2008 Location: Gwinnett GA Posts: 1,803	Re: What is this used for? Cruise control? Interesting if true. __________________ 1982 K10 SWB 1987 V20 - Sold - Doh!

03-23-2019, 08:45 PM	#4
3K144J Registered User Join Date: Jun 2018 Location: Meridian, Idaho Posts: 14	Re: What is this used for? Thanks 68Gold/White!

03-23-2019, 11:20 PM	#5
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: What is this used for? Yep, that is for an aftermarket add on cruise control. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

04-03-2019, 10:46 AM	#6
mattfranklin Senior Member Join Date: Dec 2011 Location: Moraga, CA Posts: 800	Re: What is this used for? There was a quote attributed to Charles F. "Boss" Kettering, an old time GM engineer: "Parts left off cost nothing and cause no service problems." Not sure if he really said that but I always loved the quote and try to live by it and keep my projects simple. So snip off that garbage and pretend it was never there. :-) __________________ (Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340

04-10-2019, 04:24 PM	#9
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: What is this used for? Had one of those add on cruise control things on a 76 van I once owned. Installed it myself and it worked for many years. Used two small magnets glued to the drive shaft opposite each other. I once lost one of the magnets and it still worked, however. There should be a control unit under the dash somewhere and if it's still there a vacuum control unit on the engine attached to the throttle linkage. The control unit had an adjuster to set the off and on timing of the cruise control to keep it at a constant speed. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...



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