Had my transmission rebuilt by a shop. Billet servo, shift kit ( don't know which kind) pump, ect..... The problem I'm having now is that it seems to be stuck in the gears to long. When it does shift it shifts very hard. When I go from park to drive it engages very hard. Then on a random day it shifts fine. But for the last week it's been not doing do well. Took it back to the shop and the mechanic kept it over night. Called me and told me it was nothing on his part but he did see debris in the oil and it's probably caught up in the valves and that's causing the shifting problems. He said I should flush the system and get an external tranny cooler. What do you guys think. The thing is shifting way to hard and at high rpm's (4500) to be just some debris.