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Old 05-17-2003, 11:06 AM   #1
Cowboyd
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Post Speedometer Ratio Adapter

Long time reader first time poster. Just thought I would pass on a little information. I recently had a 3.73 ring and pinion put in replacing a 3.08 ( also installed an Eaton Posi ) Wooo Hooo!! Anyway my spedometer was off before and the change made it read 81@55 MPH. Thought I could change the speedo gears but I was told I couldn't get that much change. Long story short here is a company that will make any ratio reducer you want.
Leach Enterprises in Crystal Lake, Chicago ILL. ( www.leach-ent.com ) Cost was about $70 plus tax and shipping. I will post again when I get it installed.
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Old 05-17-2003, 12:27 PM   #2
BigRed
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A buddy of mine has one of those adapaters on his truck. He had to take it off as it was leaking constantly. Thanks for the info!
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Old 05-17-2003, 08:29 PM   #3
ElGracho
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You can get gears that will probably work with your combo of tire size and gear ratio. What I think they meant was that you can't just change the driven gear. You will have to change the drive gear too. Take a look at Swervin Ervin's site here. to get some info. If you need more help, let me know, I've sucessfully done this on about five trucks.
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Old 05-18-2003, 04:32 PM   #4
Cowboyd
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Joe
Thanks for the reply. I've seen Mike's info before and thought I could solve the problem with the gear change. But my local GM parts guy told me I couldn't get a large enough driven gear.I sure hope he knew you can change the drive also!! If our speedometers are 1000 revolutions per mile the calculator said ther should be a combo that would work. Anyway to late for that I already orderd the reducer. If it leaks or is still off I'll try changing the gears.

Thanks a lot, Boyd
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Old 05-18-2003, 09:16 PM   #5
gchemist
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Try playing for the closest gear ratios you can with this web site.
http://www.tciauto.com/tech_info/speedo_gears.htm
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Old 05-22-2003, 05:43 PM   #6
Cowboyd
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TTT
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