Trans fluid is not a good idea as an engine cleaner; there's too many friction enhancers and other additives that have no business being in an engine lubricating system. There are several "motor flush" concoctions out there if you want to do an internal cleanup, but what I've found to be most effective is simply a pint of kerosene added to the crankcase of a warmed-up engine, and about 15 minutes of fast idle with no load on the engine. Drain the crankcase while the engine is still hot, and refill with a good grade of 20W-50, or 15W-40. If the pressure is still low, it's time for some internal engine work.
Jerry
