I have a NOS ring gear. There is no front or back to them.

https://photos.google.com/share/AF1...WE1zT3haWXJEMmZEWHJlamdORWNVMEtDVFRiVEV3

I heat the ring gear with a rose bud and flip it using a pair of welding gloves. I have done this on everything from GMC trucks to John Deere tractors.