Stock VB in a 47 series will not allow TC lock in 1st or 2nd, you have to modify the VB to make it work. There are a couple ways to do it, JB weld or a modified part. Suggest calling Goerends to find out the best way to do it. Some of these mods have unintended results.
Actually, the 47 or 48RE is not full electronic either, all the shifts are still hydraulic except for OD. The only real difference in control is the RE uses wheel speed to electronically set gov pressure instead of a mechanical governor.