2004 comp g, trans questions.

**04whitegtp** · 09-19-2016

Recently bought a comp g that needs a motor, has newer trans put in. But the rpo list confuses me. The car had 2.93 gears and tapshifts from the factory. How can i identify the new trans to check gear ratio?

Sent from my SM-N920P using Tapatalk

**rickisrad** · 09-19-2016

a comp G has 3.29 gear ratio

**rickisrad** · 09-19-2016

I believe it is the 9th code FR9 which is the 3.29 final drive.

https://www.facebook.com/GM3800Tips/posts/577991379016695

A Long Note on 4T65E transmission swaps.
I get a lot of private email question about replacing a transmission with one from a Junkyard. I am not an expert on this topic, and I encourage you to consult an expert. I am writing this to save myself the long email responses I give to this question, and to show you that not all 4T65E transmissions are interchangeable, although they look alike. Guys with the comp g package or the Impala police option often find this out the hard way.
Your car and the potential donor car will have a tag in the trunk (usually under the spare tire cover) that lists the RPO codes for your car, along with your VIN. RPO=Regular Production Order. Several of these codes relate to the transmission, and you will need them to begin to find a proper match. If you can’t find the RPO tags, you can look up the RPOs for a nominal fee ($5) according to the VIN number at the following website: www . compnine . com .
I know these transmissions are different in at least 5 areas, and you have to match each area for a proper swap.
FIRST is the transmission type, which relates to torque converter size, the strength of the internal gears, and the strength of the differential. Here are the basic types along with their RPO codes:
M15 — 245 mm (9.6 in) torque converter
MN3 — 258 mm (10.2 in) torque converter
MN7 — 258 mm (10.2 in) torque converter and heavy-duty gearbox and differential (see 4T65E-HD)
MD7 — 245 mm (9.6 in) torque converter (Chinese version)
M76 — 245 mm (9.6 in) torque converter (with all-wheel drive capability)
You will want a match these RPO codes.
SECOND is the final drive ratio. The PCM can detect the difference, and in some cars may not engage if the correct final drive is not present. Here are the RPO codes for the four different final drives used in the transmission.
FQ3 - RATIO TRANSAXLE FINAL DRIVE 2.86;
FR2 - RATIO TRANSAXLE FINAL DRIVE 2.93;
F83 - RATIO TRANSAXLE FINAL DRIVE 3.05;
FR9 - RATIO TRANSAXLE FINAL DRIVE 3.29;