Okay, i have two questions for you guys. First, what, if any, advantage does an aluminum driveshaft provide? Second, when cruising on the highway in my car, at about 70mph, my car is at 3000 rpm and thats in overdrive. Not sure what my rear gear ratio is but even so, im sure its not supposed to be at 3000 rpms in overdrive. what could be the problem. Thanks.

85 Berlinetta 2.8, Auto
91 RS 5.0 TBI, Auto <------Car with the problem

 

what kind of gears do u have?3.73 /4.11?
u sure that u r in overdrive?


aluminum driveshafts r sposed to be balanced better and keep thier balance longer...they r also lighter therfor letting your enging
spin up a little easier but not much.

 

Not knowing the exact diameter of your rear tires,
it appears that you have either 2.73 or 3.08's and are not getting into overdrive.

or somehow 4.10's were installed

 

Yes, im sure im in overdrive. When i put it in drive the rpms go up about 800. That was the first thing that i checked. By the way though, the rest of the car runs damn near perfect. She gets about 25/26 mpg on the highway so i guess im doing good. But if she does have 4.10's in her, id like to know who put them in because it wasnt me. Also, my tires are a little bigger than the stock 15's but not a lot. Thanks for the help