hi, i just upgraded from a 85mph to a 145mph speedo.but i need the 145 speedo gear for the trans 700R4.any one know the color or selling one. the dealer here in pasadena md, does not know witch one it is. when i'm driving at 35mph it reads 50mph and at 45mph it reades 65 and so on..thank you jerry




1987 camaro iroc
305 4brr
trans 700R4 auto

 

The drive and driven gears in the trans are usually swaped to adjust for a rear gear swap. I am not sure that you need to swap anything other than the cluster to make it work. Hopefully someone other than me chimes in with the scoop.

 

There is no difference in the gears, based on the speedo reading. The way a speedo works, is that the cable turns 1000 times per mile. Doesn't matter if the speedo reads up to 55, 85, 145, or 200 mph; it's still 1000 turns per mile. Bottom line is, you don't have to swap speedo gears just because you changed speedos.

The quick check for speedo gears is to drive along a stretch of road with the miles marked off, such as an expressway. Select a stretch you can drive on for about 10 miles or so, for good accuracy and precision. Observe the odometer (turns counter). If it reads the correct number of miles, then your speedo gears are right.

Did your old speedo work before this swap? Did it read right? Do you know that the speedo itself is accurate? How do you know haw fast you're going, and how do you know that the speedo is off?