Did you replace the cross shaft in the rear end so the 4:10 gears would fit? Also were you able to reuse the factory rear cover? What fluids? Thanks
No reason to replace the shaft until you install 4.56 gears. The only difference is the shaft has a flat section to clear the thicker ring gear. The stock rear cover will work with all the gears. I use Royal Purple synthetic oil. But any synthetic is fine.
I'm getting ready to do 4:10's in my car as well, what weight Royal Purple did you use? Seems there's two types....
Shelby cars tried to tell me I needed to replace the cross shaft if I went to 4:10 or bigger. I told them thats the first I had ever heard of that. Their catalog even states it. Royal Purple..what weight? Factory weight? Thanks
With the 410's how bad does it affect your gas milage? I was thinking about doing this mod but then thought about how bad it would do on the freeway!
I used the factory weight oil in mine. I lost about 2 MPG on the freeway but my mileage increased around town. I lost roughly 1 MPG city and highway combined. To me, the 4.10's are worth the loss in mileage.
+1! Mine is the auto with big and heavy 29.2" rear tires and I can still drive quite spirited and get at least 18-19 around town and near 25 on the highway.
