Hey guys, I've searched here and on the Internet, but can't find anything about it. I'd like to know what the FDR (gearset ratio) is for the 3 and 4 speed autos in a 96-99 J-body with 2.2 OHV.
I found Ben992200's Excel spreadsheet for calculating speed (excellent work!), but I'd like to know the FDR for the automatics so I can use it for them.
Thanks
Jason
North Carolina
1997 Cadillac SLS (147k miles)
2003 Dodge Grand Caravan (50k miles)
The 3 sp, 3T40/TH125C came with three different Final Drives (differentials), 2.84:1, 3.08:1 and 3.33:1. They also came with four different drive chain and gears sets, 33/33 tooth(1:1 drive), 33/37t (0.892:1 overdrive),32/38t (0.842:1 overdive) and 37/33t (1.121:1 underdrive).
Depending on what combination you have, determines what
effective drive you will have.
Example: mine had the 2.84:1 FD and the 37/33 drive chain gears, for an effective drive ratio of 3.18:1(1.121*2.84=3.18).
I changed my FD for a 3.08:1 FD and now have 3.45:1 effective ratio(1.121*3.08=3.45).
If I had changed to th 3.33:1 FD I would have had a 3.73:1 effective ratio(1.121*3.33=3.73).
Look at the RPO code list on the spare tire cover...
FP2
Ratio Transaxle Final Drive, 3.58
FX1
Ratio Transaxle Final Drive, 3.94
FX2
Ratio Transaxle Final Drive, 3.91
FY1
Ratio Transaxle Final Drive, 3.63
Great info. Thanks a lot guys!
In regards to the different drive chain sets MadJack talked about, do the RPO codes relate to the effective ratio (in a 3T40 car), or the actual FD ratio? If the latter, I wonder how you can tell which chain set one particular car has, so you can determine what the effective FDR is?
Jason
North Carolina
1997 Cadillac SLS (147k miles)
2003 Dodge Grand Caravan (50k miles)
I believe the RPOs Lenko listed are for the 4 sp, 4T40E. My rpo
was F75, RATIO, TRANSAXLE FINAL DRIVE 3.18.
To check your RPOs try
here. Check the bottom side of your spare tire cover for your RPOs.
BTW, the listing for the RPO says FINAL DRIVE, but it is actually for the effective ratio.
Mine are from GM's RPO list, 99 Cavalier. I'm sure there's more... but that's the list I have.
