If I buy a used rear with 3.73 gears from stock 3.27 and do not upgrade the stock speedo gear how off about will my mph be? Is there a place to buy just the upgraded speedo gear for the transmission?
2.73's is a big jump to 4.10's. Your speedo will be off but probably only by a little bit. You should still have somewhat of a good idea of how fast you are going.
Any local speed shop should have the gear, if not check out summitt, jegs, etc.
Spedo gears are not that expensive $20 max and changing them is not really that had. Its better then always trying to guess what speed your going in at what RPM and always having your mileage be off.
With 3.73's you want the 23 tooth (white) gear. Get it at a Chrysler/Jeep dealership. The ones ford stocks are purchased through chrysler and marked up to $20+.
Scott
with that gear i think you want the white, 23 tooth speedo gear. changing one is cake. get under the car, look for a plug on the driver side, rear of transmission, it's just above all the hangars for the mid pipe. disconnect electrical plug, remove 11mm bolt, pull sensor out of transmission, and you'll see the gear. there is a circlip retaining it on the sensor, just pop it off, replace speedo gear, and slap it back together. takes 10 mins. a shop will probably charge you a good bit for that, hope that helps...good luck man
oh yeah, that's for a 5 spd, don't know if an auto is the same....