Hello. I'm new to the Camaro world and have a question.
My speedo was telling me that i was moving about 90 miles/hour
but judging by the minivans flying by me I think I was doing maybe 75. I've heard if one were to play around with the gears in the rear end that it will throw the speedo out.
Is this true? I never know how fast I'm going. I drive a deep purple convertible, I see cops always runnin my plate, a few actually made a u-turn to follow me and check it out.
I don't want to get caught speeding doing 15 over on some bloody residential street.

thank you in advance

 

Mine under read by 25% when I got it. I pulled the diff cover to check the gears were what they were supposed to be, then checked the speedo gears to check that they were what they were supposed to be. One of the speedo gears was wrong. Previous owner must have changed it over and not bothered to swap out the speedo gears. An easy fix.

 

what he said (change the diff fluid) (then check the gears in the trans tail shaft) both jobs I think anyone who changes there own oil can more than handle

 

alright, sounds easy enough, How can you tel what gears are in there? I did a search here and came up with counting teeth but didn't find find out how many teeth to look for, for the range of gears available.

Thank you

 

I'll use mine as an example. Count the ring teeth. Mine came up with 41. The count the pinion teeth, which for me was 15. Divide 41 by 15 which gives you 2.73. Easy. Or, the ratio should be stamped on the gears somewhere.

 

Different tyre sizes can slightly contribute to the effect if the rolling radius (wheel/tyre combo) has changed.