Correct but it well documented that the stock driveshaft will cause vibration that the 3.08s don't really show until it spins faster with the 3.73's. The 3.73 will show a problem with the DS that the 3.08 never had.Yes it will work. You will have to re-calibrate your spedo, but I believe the TBI cars did this via a new gear in the tranny. No re-program necessary. 3.73:1 ratio should not cause you any troubles with vibration unless something is not correct to begin with. The disk will work fine. If you do the brake bolt mod it would make the discs more effective.
If you have the tow pack what rear do you have now? Some of the Roady Sedans (assuming we are talking about a sedan) tow pack cars came with 3.73:1 gears.
It will go down a little, but there are obvious trade-offs as you will turn more RPM's when crusing. You are also making the car more spirited to drive and your right foot will help dictate how many MPG's you will lose.
If you go here: http://www.transmissioncenter.net/, and find "speedometer world", click on it, and you will be able to get the proper gear ratio for the trans to correct your speedo for the gear ratio and tire size. Depending on what driven gear you need, I have a few for sale.Can a 95 9c1 rear end with a 3.73 gear differential fit on a 93 Buick road master with the tow package? Please help!!
I usually marked the DS so I installed it back as original. When I did the rear swap to 3.73 I did try to rotate the DS first but the vibration got worse. Flipped it back around to where it was livable until I could swap the DS and been vibration free since. It was actually a pleasure to drive on the TP doing 90+If you do have a vibration problem which seems to have occurred in about half the cases IIRC, the first solution you should try is to disconnect, rotate the shaft 180 degrees, and reconnect. This works sometimes and may save you incurring the expense of rebalance/replacement.
Are you talking about the drive gears like what you would see in a TH350? Cause I don't think that will work as the speedo is cable driven on those cars.