Lehigh requires TOEFL/IELTS scores for freshmen applicants. if English is not their native language. However, it doesn’t look like they have this requirement for transfer applicants. They may simply assume that if you have a good GPA at a US college (like your 3.78 at Stony Brook), then English skills should not be an issue.
Lehigh is a relatively small school, and it has high rates of undergraduate retention. This means that few slots open up for transfer students. According to the latest Common Data Set, they accepted 89 out of 537 transfer applicants for Fall 2016. This is an acceptance rate of only 16.6%, which was significantly lower than the freshman acceptance rate of 26.1%.
So Lehigh is a relatively tough transfer admit. You might want to also apply to some bigger universities; at large schools, the transfer acceptance rate is commonly higher than the freshman acceptance rate.
@Corbett Thank you for the reply. I also graduated high school in the USA. I emailed the undergraduate admissions about it. I hope they waive it. Do you think I have a shot for Lehigh?
As far as I know, Lehigh does not provide any data about the stats of accepted transfer students. The only info that I know of is the overall transfer acceptance rate, which is relatively low (as noted in the previous post).
You have a respectable GPA at a respectable university, so yes, you have a shot at transferring to Lehigh. But given the overall transfer acceptance rate, the odds appear to be unusually tough, so you might want to consider applying to some other schools as well.