I do not remember if my 1995 and my 2005 have the same pump and steering.
The 2005 book says for the first item for "steering wheel feels heavy" is that the fluid dteteriorated, low viscosity or mixed fluid. Correction is to replace fluid.
If this happens only momentarily it says to check steering belt and to purge air from system. Fill reservoir, run engine, shut off engine. then start purge procedure. Purge is done by fully turning the steering wheel lock to lock first with engine off and then with engine on.
Parts breadown indicates there is a flow control valve in the pump accessed via a plug. There could be debris in the valve. This is also called a "relief valve". Fluid is suppose to be Dextron II, Dextron III A/T fluid in 2005 model
Bud
USAF Retired
Pace Arrow
2003 Chev Ice Road Tracker