[Yadkin]

I rebuilt the tranny myself about three years ago using an aftermarket kit. The clutches are made of some type of fiber. The car sat for a long time waiting for the engine builder and body man. I originally filled the fresh unit with Valvoline Type F. During the break-in process I had several leaks in the cooling circuit and pan so ended up diluting it with no-name brand Type F from O'reilly.

The first issue that I had was stalling when putting into any gear. Sometimes chirping of the tires. I chalked it up to needing to be broken in, specifically the clutches. After less than 50 miles that issue went away.

Next I noticed that the transmission was taking a long time to warm up and getting progressively worse. Basically it doesn't shift into 3rd until warm. Over the course of 1000 miles or so it got excessive so I dropped the pan and found that the filter was clogged with clutch material. I smelled a slight amount of burn odor, but the fluid was clean. New filter, new Valvoline fluid and the transmission worked perfectly. Except for the warm-up issue.

I'm not sure if my current warm-up issue was there at the last service or not. I've put about 1200 miles on the car since then and the warm-up period is consistent at about 4 miles. It will shift into 3rd right away at low speeds with no load, but above 40 mph or so it stays in 2nd. After warm-up, the transmission shifts like a dream. Nice firm shifts, no slamming into gear, very predictable shifts and quiet operation.

I guess my question is, is this warm-up period (summer here) considered normal?