Hey guys, I'm new to this forum and I just recently traded my 96 mustang gt for an 81 Camaro and I'm in love. One problems that I've noticed is that the speedometer doesn't read true to the actual speed that I'm driving. When it seems like I'm going about 10-15mph, the speedo reads at about 25-30. I was wondering what I should do to have this problem fixed and what would be the best way of going about it. Thanks guys

 

Chevy used a number of different gears to drive the speedo. Most likely someone has changes the rear end gears and overlooked the speedometer.
Go here: http://www.transmissioncenter.net/sp...n_______va.htm
You should find the info you need. The gears can be ordered from GM or most transmission shop have them.

 

Yeah, I've ordered through those people before and they're really nice and helpful. They'll ask you questions to figure up what speedometer gears you need.

Also, did you recently change your tires to a lot bigger ones? That will throw off your speedo also.

This place will help you figure up your speedometer gears.

 

I agree. When I rebuilt the rear end in my 70 the speedo was off by 15 mph. I have a digital dash, so I was able to just re-program the speedo by going a measured mile. Once you get the gear ratio for the drive and driven gears, most trans shops should install them for about 60 bucks. There are also usually shops that calibrate the speedo. If you live in a large area, you should be able to find one.

 

Makes me wish I had a digital speedo now. With my rear end and tire makeup they don't make a speedometer gear with so few teeth. Right now I need a 29 - 30 tooth speedo gear and they don't exist.

 

A lot of times, changing only the "driven" gear is all you need to do. But if that doesn't get you into the correct range, you may need to change the "drive" gear as well, which requires you to remove the driveshaft and trans tail piece.
Another option is toput on a ratio adapter that screws onto the trans in place of the cable, and the cable attaches to that. They come in different percentages, and you just need to figure what percentage of adjustment you need.I have seen them for sale on ebay.

 

Yeah, I've thought about changing out the drive gear too but that will definantly come at a later date. Right now I'm 37.5% under my correct speed so I just round up to 40% and figure up my speed that way really quick in my head.

The adapters you've seen on Ebay, aren't they for electronic signal speedos?

 

Is there any way I could take it somewhere and have them fix it for me? I'm new to camaros and I don't have a lot of time on my hands due to rugby, school, work, etc. I live in Charlotte NC and I'm not too sure where I could take my car to have it fixed.

 

No, cable driven:
Speedo Adapter Used
Speedo Adpater New

 

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