Im looking at getting some 4.7s soon, but I want to do 23 splines instead of 21. But honestly I dont know how that works. Eventually dual cases are in gonna happen, but I can spend some money now and have it half done!

When you do 23 spline dual cases, does that mean that you have to change the output shaft on the transmission too, or just the one on the transfer case, I have read up about it and never really found a straight up answer!

I would think that you would have to change the output on the transmission also. But I want to know these things before I spend the money!

 

Simple version.

21 spline is what you got now stock. To get 23 spline you have to go dual cases and get a 23 spline adapter and then 23 spling 4.7 gears.

If you just put 4.7 gears in your single case it will have to be 21 spline.

 

x2 what the wabbit said- 21 spline in the front case to 23 spline in the second case is the strongest way to go with the g or w series n/a 4 cyl trans. r series transmissions have a 23 spline output. not sure if they make a 4.7 kit for the 23 spline inputs. u do not want to put a low range kit in the front one as it would multiply the torque too much to the rear case. i usualy just shift just my rear case to low range and only the front one when necessary. and stock gearing is fine with my 38's. I don't see the need for anything lower other than bragging rights.

 

Yeah I never knew how that worked. I want to do dual cases eventually, because my D/S angle in the front is horrible!! And for bragging rights, but thanks for clearing that up for me. I do have the G56 trans so I am good there!

I want to do the 4.7s in this case so that all I have to do when I get a crawl box is bolt it on!