speedometer is about 30 mph fast how to fix - The 1947 - Present Chevrolet & GMC Truck Message Board Network

84_chevrolet · 01-02-2005, 04:03 PM

hey anyone else have this problem or have a solution for my problem i have tried different things but nothing has worked and i really need a solution

Russell · 01-02-2005, 04:59 PM

Sounds like either something is wrong with your speedometer, or your transmission has the wrong gears for your rear end ratio / tire size, etc

Blue Beard · 01-02-2005, 05:09 PM

You can change the gear at the transmission.

But that will depend on the rear gears and tire size.

How much are you off in a mile?

84_chevrolet · 01-02-2005, 08:06 PM

i am running a 700r4 trans with a np208 transfer case 4;11 gears and 33x12.50 goodyear wranglers

75Chevy90Kawi · 01-02-2005, 09:14 PM

when the previous owner put big rims and bigger tires on my truck, it caused the speedo to read low, and although i havnt done anything yet, i've heard that you can just take it to a chevy dealership and have them recalibrate the speedo for you

Blue Beard · 01-02-2005, 09:22 PM

Any good speedometer shop can change it, but you need to decide all the options first.

ElGracho · 01-02-2005, 09:41 PM

First off, if you want help, we need more information. When you say your speedo is off 30 mph, is it always 30 mph off? Maybe someone took the needle off and put it back on wrong. This is almost never the case, but based on your description, it's tough to tell. If it's not really always off by 30 mph, at what speed is it off 30 mph? Like Blue Beard said, a more accurate way to trouble shoot is to use the odometer and see how much it reads on a measured mile of highway. For instance, if you drive 1 mile and your odometer reads .7 miles, your speedo is off 30%.

Look here, here or here for info on how to correct this.

84_chevrolet · 01-02-2005, 10:19 PM

hey that is a good information site is it the same for 4x4 with the speedo gears in the transfer case and it is off 30mph at 55 mph when your going 55mph the speedo reads 85mph and it is a 2wd speedometer is there a difference between a 4x4 speedo and a 2wd speedo?

piecesparts · 01-02-2005, 11:03 PM

Sometimes the speedo head is the culprit. I had to get another speedo out of the salvage yard and replace on the son's truck. This brought the speed into a realm that I could control with changing out speedo gears. A speedometer shop is sometimes a little hard to find in your general area, so there is always another way.

01-02-2005, 04:03 PM	#1
84_chevrolet Truck CRAZY! Join Date: Mar 2004 Location: douglas Posts: 81	speedometer is about 30 mph fast how to fix hey anyone else have this problem or have a solution for my problem i have tried different things but nothing has worked and i really need a solution

01-02-2005, 04:59 PM	#2
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Sounds like either something is wrong with your speedometer, or your transmission has the wrong gears for your rear end ratio / tire size, etc __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

01-02-2005, 05:09 PM	#3
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	You can change the gear at the transmission. But that will depend on the rear gears and tire size. How much are you off in a mile? __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-02-2005, 09:14 PM	#5
75Chevy90Kawi the green machine Join Date: Oct 2004 Location: marysville washington Posts: 333	when the previous owner put big rims and bigger tires on my truck, it caused the speedo to read low, and although i havnt done anything yet, i've heard that you can just take it to a chevy dealership and have them recalibrate the speedo for you __________________ 1975 Silverado - 450 horse crate 383 stroker, 20" Centerlines, Flowmaster exhaust, Hooker headers, full MSD ignition & more... 2003 Suzuki TL1000R 1985 Kawasaki JS550 hull - project ski - WILL have - 650, footholds, custom paint, 4* bars, bilge setup, and more... My pictures

01-02-2005, 09:22 PM	#6
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	Any good speedometer shop can change it, but you need to decide all the options first. __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-02-2005, 08:06 PM	#4
84_chevrolet Truck CRAZY! Join Date: Mar 2004 Location: douglas Posts: 81	i am running a 700r4 trans with a np208 transfer case 4;11 gears and 33x12.50 goodyear wranglers

01-02-2005, 09:41 PM	#7
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,550	First off, if you want help, we need more information. When you say your speedo is off 30 mph, is it always 30 mph off? Maybe someone took the needle off and put it back on wrong. This is almost never the case, but based on your description, it's tough to tell. If it's not really always off by 30 mph, at what speed is it off 30 mph? Like Blue Beard said, a more accurate way to trouble shoot is to use the odometer and see how much it reads on a measured mile of highway. For instance, if you drive 1 mile and your odometer reads .7 miles, your speedo is off 30%. Look here, here or here for info on how to correct this. __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

01-02-2005, 10:19 PM	#8
84_chevrolet Truck CRAZY! Join Date: Mar 2004 Location: douglas Posts: 81	hey that is a good information site is it the same for 4x4 with the speedo gears in the transfer case and it is off 30mph at 55 mph when your going 55mph the speedo reads 85mph and it is a 2wd speedometer is there a difference between a 4x4 speedo and a 2wd speedo?

01-02-2005, 11:03 PM	#9
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Sometimes the speedo head is the culprit. I had to get another speedo out of the salvage yard and replace on the son's truck. This brought the speed into a realm that I could control with changing out speedo gears. A speedometer shop is sometimes a little hard to find in your general area, so there is always another way.



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