Rattling in Manual Second and First

[gbw350]

I have a 200-4R behind a very torquey SB400 (nearly 500 ft lbs) that was built about 6 months ago with an Art Carr Kit and a PTS Billet Converter running about 3000 rpm stall, exactly where Bruce said it would. The trans shifts perfectly in OD and in Third, but when I put it into manual second or first to pick the shift points myself, it makes a rattling noise at low rpms and increases pitch as I rev. It don't notice any noise in second or first when I let the trans shift for itself in OD or 3rd. Could it be the Pressure Regulator?

Thanks in advance,

GBW

 

[gbw350]

Well, I doublechecked this morning, and I could have sworn that the fluid level was high enough, but it turns out that the trans was a pint low. Added a pint, and the noise went away.

GBW