Hi, I am no stranger to rebuilding transmissions, but this one has me stumped. Rebuilt the trans using suncoast parts, triple disc, and upgraded snap ring on forward drum, problem surfaced about a 1000 miles into it. No codes, but sometimes no forward gears, always have reverse, works most of the time, but happens when trans is warm. My deduction has been a seal that's seeping or sticking boost valve, but seems to me with a sticking boost valve reverse also wouldn't work. When it finally does work, it still has all gears like nothing is wrong Haven't hooked up a trans pressure gauge yet as it works fine when it does. Sorry for the long post, but wanted everyone to get the picture. Thanks.