So this morning I was trying to have a conversation in mandarin with my Malaysian Chinese friends. During the conversation, I pronounced 辆 in 4th tone just the way I learned online. Apparently, they said it is supposed to be pronounced the 3rd tone but when I went home and searched it up on a few dictionaries, all of them pronounce as 4th tone. I am not sure if it is just my friends that are mistaken or if there are more than one pronunciation for 辆. What do you guys think?
I don't know about Malaysian Mandarin, but in Standard Mandarin (both ROC (Taiwan) and PRC),「輛」is pronounced in the 4th tone.
What is indeed pronounced in 3rd tone is「兩」.「兩」is the original character for「輛」, so in ancient texts when「兩」is used as a word to do with vehicles/horses, it is also pronounced in the 4th tone.
The standard way of pronouncing 輛 is the 4th tone, however Malaysian Mandarin - similar to Singaporean Mandarin - is slightly different from standard Mandarin and influenced by dialects of their ancestors (I think Hokkien and Cantonese are the most common).
Most Malaysians will understand standard Mandarin, but since they pronounce some words differently, I imagine it can be confusing for Chinese learners.
Wikipedia entries on Malaysian Mandarin: https://en.wikipedia.org/wiki/Malaysian_Mandarin Singaporean Mandarin: https://en.wikipedia.org/wiki/Singaporean_Mandarin