The yellow thing around the u joint is lithium grease but i guess it was too thick to penetrate into every cracks and crevices so it didn't work
Turn on the engine and generously spray the U joint. Turn the steering wheel around to expose different side of the u joint and spray.
Do the same thing with the upper u joint connect to the steering wheel. The shaft it self is hallow so spray generously inside that shaft too.

Make sure you spray it generously and let it soak and seep into every crevices for a few minute before take it out for a test drive.
I dont know why greasing the u joint work I guess because the u joint is stiff and under immense pressure as the steering wheel being turn. The clunk could be the result of the u joint banging against the shaft it self as the energy being release.
I hope this help.
