Trans sending unit???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

westbrookw · 12-26-2008, 09:52 PM

I have just replaced the gears from 3.08 to 3.73, where can I find a sending unit that will give me the correct speedo? I have a turbo 350 automatic trans. Thanks for any help.

low'n slow · 12-26-2008, 11:11 PM

You can do several things, first change out the gear in the transmission where your speedo cable goes in. You may or may not have to change the gear on the mainshaft of the transmission. The other thing you can do is get a little box that changes the ratio for you. Or you can do a combination of the 2. The little boxes come up on the sales forum occasionally. Good luck.

westbrookw · 12-26-2008, 11:13 PM

^^ Thanx. I was going to try the gear. Where can you find these?

JimKshortstep4x4 · 12-27-2008, 06:34 AM

Here is an article on selecting the gears you need and a source link is included in the article.

http://chevelleengineer.home.comcast...eer/speedo.htm

Jim

70GMCer · 12-27-2008, 08:02 AM

Gears your local GM dealer

Wrenchbender Ret · 12-27-2008, 11:45 AM

The 350 is easy to calibrate. Take out the driven gear & it will have the number of teeth on it or count them. Try one with about 2 more teeth on it. You can get them from a dealer or Carquest has them in their Motor -Mite line. If you have a trans. shop that will help you, they always have an asssortment of them. After you put it in match the odometer up with the mile markers on the freeway. Then you can change it again if ness. to get it real close.

piecesparts · 12-27-2008, 12:42 PM

Any tranny shop or go to the Chevy parts counter.

westbrookw · 12-27-2008, 09:03 PM

Quote:

Originally Posted by JimKshortstep4x4

Here is an article on selecting the gears you need and a source link is included in the article.

http://chevelleengineer.home.comcast...eer/speedo.htm

Jim

Thanks Jim, That article is really good. Thanks to everyone. I really appriciate it.

12-26-2008, 09:52 PM	#1
westbrookw LET'S GO...MOUNTAINEERS Join Date: Oct 2007 Location: Williamstown, WV Posts: 339	Trans sending unit???? I have just replaced the gears from 3.08 to 3.73, where can I find a sending unit that will give me the correct speedo? I have a turbo 350 automatic trans. Thanks for any help.

12-26-2008, 11:11 PM	#2
low'n slow Too Dumb To Know Better Join Date: Nov 2005 Location: Texas Posts: 882	Re: Trans sending unit???? You can do several things, first change out the gear in the transmission where your speedo cable goes in. You may or may not have to change the gear on the mainshaft of the transmission. The other thing you can do is get a little box that changes the ratio for you. Or you can do a combination of the 2. The little boxes come up on the sales forum occasionally. Good luck.

12-26-2008, 11:13 PM	#3
westbrookw LET'S GO...MOUNTAINEERS Join Date: Oct 2007 Location: Williamstown, WV Posts: 339	Re: Trans sending unit???? ^^ Thanx. I was going to try the gear. Where can you find these?

12-27-2008, 06:34 AM	#4
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Trans sending unit???? Here is an article on selecting the gears you need and a source link is included in the article. http://chevelleengineer.home.comcast...eer/speedo.htm Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

12-27-2008, 08:02 AM	#5
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Trans sending unit???? Gears your local GM dealer __________________ 1997 GMC Sierra Ext 1965 Mustang

12-27-2008, 11:45 AM	#6
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,208	Re: Trans sending unit???? The 350 is easy to calibrate. Take out the driven gear & it will have the number of teeth on it or count them. Try one with about 2 more teeth on it. You can get them from a dealer or Carquest has them in their Motor -Mite line. If you have a trans. shop that will help you, they always have an asssortment of them. After you put it in match the odometer up with the mile markers on the freeway. Then you can change it again if ness. to get it real close.

12-27-2008, 12:42 PM	#7
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Trans sending unit???? Any tranny shop or go to the Chevy parts counter.



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