I started welding the diff first doing very small welds with MIG:

Next I removed driveshafts and started to weld with electrodes (312-17 / LIMAROSTA 312 2,5mm). This is very time consuming process since I only can weld a short while until I need to cool down the diff because I don’t want to let it too hot. Today I was able to do the first deep welds for each 4 corners and both sides, totaling to 8 welds and some 10-15min cool down between each weld. Next I will weld more and try to adhere the gears properly to the frame.

Seems that choosing electrode welding was the right choise since there is also small amount of plastic behind the second largest gears. Mig welding would have been very spotty because of that. And also those electrodes which I’m using seem to be very easy to weld and able to melt the steel deep so the gear teeths are disappearing (melting) easily to one lump of steel. I will probably continue this at Saturday since tomorrow will go with other activities.