Gearing calibration problem

[90ARAPAJ]

I have a 98 T/A and i put in 3.73 gears but the thing is when i had the gears put in back in 1999 they didnt have a progammer to calibrate it so i had to drive it with 3.73 but the computer thought it was 3.23 so i put alotta miles on my car. I have the hypertech set to 4.56 gears to get my miles back but i really dont like the way it is. when i set the redline to 6200 RPM it redlines at 5900 but then ill add 1-2 MPH on the 1-2 shift and itll go to 6100 and itll bounce. i tried running the setting of 3.73s and i liked it but i want my lost miles back. What can i doo to possibly set my miles back??

[Knight]

I don't think there's much you can do, besides what you're doing now. I would think it would only matter if you were selling the car, anyway. If you don't plan to sell the car, you know how many "actual" miles are on it. Tampering with an odometer gets into an area of federal laws, I don't recommend it.

[pajeff02]

^^ This. Select the appropriate gear ratio so your PCM can shift the transmission properly and forget about it.

[2002ssslp]

What about switching the instrument cluster. I think the memory is in the cluster and you can always sell yours to make up the money you spent.

[90ARAPAJ]

^^ This. Select the appropriate gear ratio so your PCM can shift the transmission properly and forget about it.

yes but it kills me that i lost all those miles....with the 4.56 program it doesnt let my car shift till 2300 RPM but with the 3.73 programed it shifts at 2000 and when i floor it with the 4.56 program it redlines but goes to 35mph and with the 3.73 it goes to 42mph soo tell me how that works lol

[pajeff02]

Something else has to be off in your tune or your transmission is having issues.

[2002ssslp]

Send the PCM to Frost and let Steve deal with it.

[JohnnyBs98WS6Rag]

yes but it kills me that i lost all those miles....with the 4.56 program it doesnt let my car shift till 2300 RPM but with the 3.73 programed it shifts at 2000 and when i floor it with the 4.56 program it redlines but goes to 35mph and with the 3.73 it goes to 42mph soo tell me how that works lol

35MPH w/ 4.56 gears is the same driveshaft speed as 42MPH w/ 3.73s. In both cases, flooring it until it shifts, you get to the same engine / driveshaft RPMs at the shift point, but the speedo reads different because the PCM is calculating MPH based on the gear ratio it thinks it has.

WRT the different non-WOT shift RPM, the PCM must be compensating somehow. Maybe your programmer automatically raises the shift RPM for the higher gear ratio, part-way compensating for the slower MPH at the shift point??