jstockert

Anyone have input on this accu-speed to correct the speedometer on 1997 with analog odometer? Good or bad.
I have 35's with 4.56 gears and speedometer is about 18.5% fast. Thanks

Carcrazygts2

what was the factory gear ratio? the only true way in a 97-98 is by changeing the speedo drive gear on the VSS on the tailshaft of the transmission/transfercase.

jstockert

3.55. I have found a calculator online to see which gear I would need and I came up with a 23 tooth which I know ford does not carry. Can not find anyone who does. Maybe you know something I don't about this.

Carcrazygts2

you need to find out if you have a 7 tooth or 8 tooth speedo drive in the transfercase. 23 tooth gears are available. But I believe the chart you found is wrong. I'm running 3.73 with 34's and using a 15 tooth and my speedo is only off by .5mph @ 60

http://www.transmissioncenter.org/Fo...eter_Gears.htm

jstockert

I have the 19 tooth with 8 gears. My setup is 4.56 gears with 34.8" tires. Per gps at 50 mph speedometer says 59. At 25 per gps speedometer says 29-30. I ordered a 21 tooth from ford today to see how close it gets me. Not any good reviews on the accu-speed.

jstockert

Well I installed a 21 tooth gear. Will see if that closes the gap.

jstockert

@carcrazygts2 I read what you said but it did not register till now. I was dividing my current gear(19) by the percentage my speedo was over 19/1.19 = 23.45 which I thought I would need a 23 tooth gear. But in reality I should have did this math. 19x.81=15.4 tooth.
By changing to a 21 tooth I will make the speedo off by a even higher percentage because a 21 tooth will spin faster than a 19 tooth. Anyway I will drive it tomorrow and see for sure. Anyway thanks again for you help.

Well test drove truck this morning and I guess there is a reason people say always go with your first thought. The 21 tooth reduced me from 59 speedo 50 actual to 54 speedo 50-51 actual. I wanted to update for future references.