Kevin Hart's Ex-Wife -- I Made Peace with His Fiancee ... Even Before the Escalade

Kevin Hart handed his ex-wife keys to a new Caddy, but she gave him something pretty awesome too -- peace between the mother of his 2 children and his new fiancée.

Torrei Hart tells TMZ, the 2015 Escalade Kev gave her for her 37th birthday came on the heels of her squashing all old beef between her and Eniko Parrish.

It's no secret ... the Harts' bitter divorce included nasty Twitter rants and cheating accusations -- but Torrei says things are so cool now with the future Mrs. Hart ... the ladies even hang together at the kids' hoops games.

Torrei adds Kevin was so supportive when he knew she needed a new ride ... he even let her pick out ANY vehicle she wanted.

Bottom line ... that crap they say about grudges might be true.