Speedo is 15mph off.

88 Fox GT

Active Member
Nov 18, 2002
1,674
0
36
Iowa
Got pulled over for doing 65 (in a 55 while speedo said 50). Luckily the cop said I had a nice car and stuff like that and I had a clean record and he believed me about the speedo because I was being honest and courteous to him. So, he said he wanted to keep my record clean and he let me go.

Now, it's time to figure this **** out incase I run to some a-hole cop next time. If I recall correctly, last time I checked my speedo gear it was red and I counted 21 teeth. According to this chart, that's for 3.73 gears.

Manual Transmissions with 7 Tooth Drive Gear

1983-1989 T-5 OEM
Pre 1993 T-5 Aftermarket
1996-1998 Cobra T-45 OEM
All Tremec Transmissions

Item Number
Description
C0DZ-17271-A
2.73 Gear Ratio / Maroon 16 Speedo Gear

C0DD-17271-B
3.08 Gear Ratio / Yellow 18 Speedo Gear

C0DZ-17271-B
3.27 Gear Ratio / Pink 19 Speedo Gear

C1DZ-17271-A
3.55 Gear Ratio / Black 20 Speedo Gear

C4OZ-17271-A
3.73 Gear Ratio / Red 21 Speedo Gear

Jeep Part #j3167393
4.10 Gear Ratio / White 23 Speedo Gear

This chart also says I should be using the maroon 16 tooth gear for my 2.73 gears. I don't know how it got the wrong gear in the first place unless at some point they had 3.73s in it. I just want to get the right gear in it until I get my other rear end and install my 3.73s. Would the 21 tooth make my speedo 15 mph too slow if it's supposed to be a 16 tooth?
 
yea... if you have 2.73 you need to put the 16th one back in... it would make it that much off...

i myself have the same problem... when im doing 70mph im going 85! i put a need speedsensor and i have the right gear but still is off... i dunno what my problem is!