Help with my Freelander 2

Hi all, my first post on here and hoping for some advice. I have a 2008 FL2 HST Auto. Its great but I'm having some issues with the auto gear selector - it's fine moving down (Park to Reverse/Neutral/Drive) but is really notchy moving back up to Park, sometimes needing some force to get it to move up from drive. The spring has gone in the selector lever button, which is common as far as I can see, and I've ordered a new spring fir that. But would that effect the sector moving only in one direction? If not, is it an easy fix? I don't mind trying to repair/replace things myself if anyone knows of a decent guide to replacing the selector mechanism? Many thanks in advance. It also needs a new rear diff as it's currently singing to me - any advice on where to source a replacement whether new or reconditioned? I have someone able to fit it.

Maybe the cable for the auto has gone still, and needs lubrication?

The diff can be reconditioned by a professional or DIY, like I did. It's best to do it ASAP, as mine seized solid, resulting in me having to control a rear end skid, although to be fair, my diff was empty of oil.