Rack- pressure valve,fluid questions

I am replacing the rack on my 98 Windstar 3.8, my questions are- Do I need to put the retainer washer in with the pressure valve? I took my old one off and it did not have one, so I was not sure that it is that important as long as I have the valve in there?

- Would Valvoline Syn power power steering fluid be sufficient or should I use a synthetic transmission fluid. Also If I use a transmission fluid can I use lucas transmissio additive to help with friction?

Thanks for your help

I can answer the fluid part of your question, you need a ATF that meets the Mercon or Mercon V specification.
You should not need to add any additive, and I would recommend against it.
You still need to keep the fluid fresh, and you will be fine.

I recently replaced the rack on my '99. I had the subframe dropped for other work and it seemed like a good idea at the time. Figured it would tightened up the steering/play. I don't remember any retainer washer ... but there may be a model difference.

I have been using only the Valvoline for many miles/years on several cars. Seems to work great.

I went ahead and got some Mercon V for the power steering/rack.

Anyone else know if it is safe to install the pressure valve without the retainer????

Thanks for the replies

Hi, new to this forum but have found lots of good info browing through. I have replaced the steering rack on my '98 3.8 windstar-the question I have is when I set the old rack down on the garage floor, a small metal 'button' dropped out from one of the hose ports. it is open on one end and has a very small opening at the other end. Is this the pressure valve referred to here? I am guessing it goes in the pressure hose port, but which end points in? I haven't been able to find any diagrams that show this part. Thanks for any info...