Ok so when I bought my Jeep, driving home it was reading about 52-53. Wife was following in her Durango and said I was doing about 65. Her GPS Confirmed 65-66. MY Rpms were just a hair below 2000.
So I knew I had to replace my Speedo Gear. Last couple days the speedo will not read at all when starting out, then sometimes read 80 continuously. Other times it will max. Then after about 5 minutes it will start reading "correctly" (Meaning it goes up and down with regard to road speed). After VSS replacement it still wont work initially. I am going to test the wires AND read a couple other tests I can do on the Speedo itself and will get to ya'll on that.
SO I replaced my VSS sensor today and noticed I have a 40 tooth Speedometer gear (Orange with a big fat 40 on it). The "housing" is correctly set with the 39-45 mark facing down.
The Tag on my Diff says 3.55, I have 31" tires. I have ran a calculator that says at 65 I should be about 1956 rpms with that setup which IS VERY close to what I was at when the wife said I was doing 65.
According to the Gear Selector Chart, I need a 32 tooth Gear and that 93 electronically driven speedos were a short shaft. But I have pulled the gear out and it's most definitely a Long shaft.
Would a 40 tooth Gear on 31" and 3.55 read 12-14 mph slower than actual speed or is something seriously wrong lol.
For the record I ordered a 32 tooth long shaft gear tonight.