A quick question : we installed a rebuilt by S and G 60 PS box , ( always good stuff in past ) and a used 60 ps pump . We modified the 60 pump bracket to be a solid mount and replaced the pump seals, painted it etc . ( rock hard seals by the way , so always do this ) . Needs real seal puller to do right . So - it did not work . Violent shaking of high pressure hose , noise if you turned wheel , no real assist . Not air . We removed and replaced PS control valve with NOS (we had) spool valve and return line pressure regulator, in separate steps (on top of the PS box ) No change . Thinking was the big piston stuff in box can’t possibly vibrate that fast , many times a second , hose jumping an inch but still no assist (?) . But spool valve might ? So initial thought , the pump is probably ok , looked perfect inside , given the hose jumping (= hi psi) nothing in the pump really but the psi spring and regulator setup . So ( a big “who needs this” feeling growing , —at in having to pull box again! ) —we tried an old pump , long shot . All is fine . We don’t know why , ?? — but we had noticed vibration rate changed with rpm , but it would anyway as pump psi grew with rpm? Throwing this out to all —to help prevent pulling the box for nothing , — but also maybe someone has seen this , or knows what goes wrong in a PS pump to cause it ? Has anyone seen this? I never have . We did not have psi gauge that goes that high ... may have found it though . Step 1 now. fyi J Sent from my iPhone not by choice -- For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang --- You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group. To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion on the web visit https://groups.google.com/d/msgid/chrysler-300-club-international/D148F73E-4B6C-47BB-91AB-A3CB879B74A7%40gradyresearch.com.