[svsantosh]

1) 3Rd gear stuck and now slipping - been there, done that :(
Your mech was correct and nearly solved the issue but sadly over did it a bit. The billet steel lock is a tiny piece of metal that holds 3rd gear in place. If that is a tad big in size (these are non standard parts from local manufacturers mind you) - my mech instead of hammering it short - FILED it with a filer, little bit at a time. Now it slots in and out of 3rd perfectly and holds it there without slipping. I suggest you get a new GB lock set and just replace the 3rd gear lock and custom file it bit by bit all over again.

2) Float - that missing plastic is still inside your tank! PS - If your meter went from zero to full without float it was perfectly fine in the 1st place. the float is kind of potentiometer - current is restricted when the plastic goes down, and increases to full amp when float is all the way up. Kind of radio tuning stick...

3) Shackle - Lucky you! It was a case of negligent maintenance. Get a general checkup (mech lang) every 3000Kms. Means tighten all nuts and bolts (loosen where applicable - binding bolts!, only your mech can tell) and grease all points. There are 30 points in a jeep.