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| | | | Joined: Sep 2004 Posts: 17 Apprentice | | Apprentice Joined: Sep 2004 Posts: 17 | (1) I have installed a 350 trans and a 5 lug rear end from a 78 GMC in my 66 C-10. Is there anyway to figure out which speedometer gears to install in the transmission without counting the teeth on the rear end gears?
(2) Are the speedometer gears color coded per number of teeth. | | | | | Joined: Dec 2006 Posts: 1,464 Shop Shark | | Shop Shark Joined: Dec 2006 Posts: 1,464 | The speedo driven gears are color coded. Do you know how far off you are? Once you determine that, you can just adjust your tooth count (on the speedo gear that is, don't make a dental appointment). For each tooth less than what you have, the speedo will read about 5mph more, for each tooth more, it will read 5mph less. You should be able to get pretty close this way. | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | Waldo is right on. Compare the odometer reading with the mile markers on the freeway. The 350 has a wide selection of gears & they are readily available. You do not have to change the internal gear but if you make a big change you may have to change the holder.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Sep 2004 Posts: 17 Apprentice | | Apprentice Joined: Sep 2004 Posts: 17 | Thanks guys, I apreciate your help. | | | | | Joined: Nov 2006 Posts: 9 New Guy | | New Guy Joined: Nov 2006 Posts: 9 | I am having a similar problem. TH 350, new speedo and I am running 2:1. Where are these replacement Gears found and what is the holder? | | | | | Joined: Dec 2003 Posts: 1,554 Shop Shark | | Shop Shark Joined: Dec 2003 Posts: 1,554 | Most Chevy dealerships sell them at the parts counter. | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | What I called the holder is the housing that holds the driven gear. The housing is made for several size gears & the number of teeth on the gears it will handle are cast into the housing. You can go 1 tooth over or under what is on the housing but if you have to change more then that you need to get a different housing. Carquest has the gears in their Motor-mite line. A trans. shop often has a lot of these parts laying around if you can get them to help you. Or a G.M. dealer. If you have an early 350 trans. with the small housing, disregard all the above.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Sep 2006 Posts: 42 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2006 Posts: 42 | Hey 64 & 66 C10. Try Googleing 350TH speedometer gears. You'll come across a couple of sites that give the color and number of teeth of the speedo drive & driven gears. The driven gear, ( the one that is attached to your speedo cable) is quite easy to change out. The drive gear, that is internal will require removing the tail end off the transmission, if you need to change it out.
Hope this helps. | | | | | Joined: Nov 2006 Posts: 9 New Guy | | New Guy Joined: Nov 2006 Posts: 9 | Great info!! Thanks Dale, Wrenchbender and Oldkoot..I will check this out this week. | | |
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