Pronouncing the Past Tense '-ed' Ending

There are three different ways to pronounce the –ed ending at the end of regular past tense verbs in English.

The pronunciation of the –ed ending depends on the final sound in the verb.

If the verb ends in a –d or a –t, the –ed ending is pronounced as a new syllable, /id/.

If the verb ends in a vowel sound
or
a voiced consonant (l, n, r, b, g, m, z, s, v),
then the –ed ending sounds like a /d/ and does not create a new syllable.

If the verb ends in an unvoiced consonant (p, k, f, gh, sh, ch, ss, c, x),
then the –ed ending sounds like a /t/ and does not create a new syllable.

(If you are unsure if a consonant is voiced or voiceless, put your fingers on the side of your neck and feel for the vibration that occurs when you say voiced consonants: l, n, r, b, g, m, z, s, v).

This is explained in this webpage (Woodward) with a You Tube video

There are other internet resources explaining this:
EnglishClub: Pronunciation : -ed (with a sound file - with American accent)
Tanya Trusler, 'Pronunciation of Past Tense Endings' April 12, 2018