叮叮噹噹 Weapons Clattering Outside
好妖精，一縱雲光，直到洞口。又聞得叮叮噹噹，兵刃亂響。三藏道：「徒弟，外面兵器響哩。」行者道：「是八戒揉鈀哩。好妖精，一纵云光，直到洞口。又闻得叮叮当当，兵刃乱响。三藏道：「徒弟，外面兵器响哩。」行者道：「是八戒揉钯哩。
逐句解 Line by line
Good fiend! With one bound of cloud-light she went straight to the mouth of the cave.
The storyteller's exclamation of approval, and it is given to her. She has been 好妖精 — good fiend — only once before in the chapter, and the formula is usually reserved for the pilgrims.
And they heard a clanging and clattering, weapons ringing in confusion.
The sound arrives before the sight, which is how the chapter has been staging every arrival. 叮叮噹噹 is a four-character noise-word for metal on metal, and in 聞得 the 得 is dé, the full reading fused onto a verb of perception.
Tripitaka said, "Disciple, there are weapons sounding outside."
He is still riding on her back and giving a running commentary. Eleven characters, and the ordinariness of it is the comedy.
Pilgrim said, "That is Bajie working his rake."
揉鈀 is to work or rub the rake — Bajie polishing his weapon out of boredom. He and Sha Monk have been standing at that hole for the entire second half of the chapter.
Pilgrim identifies the noise instantly and correctly, from inside a fiend's stomach, with his master on her back. He knows what Bajie sounds like when he is bored.
The detail is a small kindness to two characters the chapter forgot. Bajie and Sha Monk were told to block the cave mouth around fifteen hundred characters ago and have not been mentioned since. They are still there, and one of them has been cleaning his rake.