PontiacBonnevilleClub.com

I used a tranny out of an SLE in my 2000 SSEI but I opened it up and swapped the differentials. If I remember right the incorrect gear ratio code was hidden but found with a Tech II. It destroyed itself after a year due to the high line pressure I'm assuming. Now its all brand new again and I still have the incorrect ratio code. What part did I leave out when I swapped my HD Diff?

Im not very handy with a transmissions internals but im pretty good with a google search lol I found a link that may help.
Quote~~"You ABSOLUTELY DO NOT want to install the HD version of the trans in a car that did not come equipped with it originally UNLESS you have the ability to reflash the PCM to correct for the change in final drive ratio. Failing to do this will set code P0730 Incorrect Gear Ratio and default the transmission to max line pressure."
http://www.bobistheoilguy.com/forums/ub ... er=2537753
*post is half way down, it was posted by C5Shark
You have to match a PCM with the final drive ratio of your tranny...or reflash if possible


*Edit* it has to be a supercharged PCM with the matching final drive gear ratio

correct when you swapped the SLE Trans into the SSEi with the SSEi Diff, you made your trans a 3.29 ratio. the SSEi trans is a 2.93.

you will need to install the correct Supercharged Trans or get the PCM reflashed with a tuning software package to make the changes

But my car is an SSEI and I used my diff out of my tranny so shouldn't my gear ratio still be the same? Everything else was just clutch packs and valve body.

No..

The Diff in every 96-03 SSEi is a 3.29 Ratio Diff, But it has a 37 Drive and 35 Driven gears making it an Overall 2.93 Ratio..

Now the SLE from 98-05 used a 3.05 Ratio Diff, But it used a 35 Drive and 35 Driven gears ( 1:1 ) so the overall is 3.05 as the drive and driven are the same..

So being that you used an SLE trans and you installed the 3.29 SC diff you have a 35 drive and 35 driven ( 1:1 ) making the overall ratio as 3.29 as opposed to the 2.93 that you should have.

Wait but my car is an SSEI so why should I have a 2.93 not a 3.29 if I'm reading right

Jeff, you have a 3.29 Ratio Diff, But its being Over Driven with a 37 Tooth Drive Sprocket and a 33 Tooth Driven Sprocket..

The Problem is that the trans you have in it now has a 35 Tooth Drive Sprocket and a 35 Tooth Driven Sprocket meaning its not Over Driving your 3.29 Diff.. So your actual overall ratio is 3.29..

The 3.29 has to be Over Driven to attain a 2.93 overall ratio..

Simplest solution would be to flash the pcm with the 3.29 shift tables.