I had my diff welded by a friend who has done it a bunch of times for friends and his diffs have always held really well. I ran a drift event last month after filling a sealing the diff; My question is I since he Mig welded it do I need to drain it and fill it with fresh oil since it’s Mig and not stick?
The important thing is that the welding and sealing were done right. Whether it's MIG or stick welding doesn't really matter for the oil. But, after a drift event, it's a smart move to check the oil in the diff. If it's been welded, it's been through a lot, so you want to make sure the oil is still in good shape. If you see anything off, like dirty oil or metal bits, then it's time for a change.
