hello, please ignore Cowabanga.
The problem:
when you post a question and if this question doesnt get answered in first day it will probably fall on 2nd page(or lower pages). Most people wont check this pages. And actual default forum setting only shows topics that are active in last two weeks.(unless you change the setting).

Next time if you dont get any answer in 1-2 days, bump your thread up so more people can see it.

Now for your question, where did you got stuck exactly? you have working truck only need trailer physics?