Hi;

I have transferred one domain and have two more expiring Jul/18 and Oct/18 for transfer.

If I transfer them, do I lose time from transfer to expiry, or keep time?

Thanks;
Bill

You do not lose time when a transfer any domain name. On the contrary, you get one extra year.
As far as I remember, the only case when you do not get one extra year is transferring.uk domain names.