2002 300m limp mode
 

i just picked up a 2002 300m special 4 days ago and have already replaced/fixed just about everything that goes wrong with these cars, BUT the limp mode issue.

when the cars cold its drives fine, but as soon as it warms up its hit or miss as to if its going to stay into normal driving habits, ive picked up a used solenoid pack from a local junk yard from a 99 300m, what i want to know is how can i see the date code of this sol pack, and make sure its not in the range of the bad packs? i plan to clean the unit very very well with brake kleen, and i was also wondering if i can reuse the valve body gasket if it does not tear? and is there a specific order i have to tq the bolts down to?