[ImperialCrown]

Welcome to Allpar. Is the P/S reservoir filter screen possibly plugged with debris? This filter isn't serviced separately. Any whine?
The reservoir should be replaced whenever an old pump sends debris into the system following a thorough system flush if the pump comes apart or the fluid gets contaminated.
At higher RPM the pump may be able to overcome the restriction.
If you had P/S assist for 5 minutes after the pump replacement then everything else sounds OK.

ATF+4 (MS-9602) is an acceptable replacement fluid, but you don't want to mix old and new. See TSB #19-005-03:

http://www.wjjeeps.com/tsb/tsb_wj_1900503.pdf

 

[lou4x2]

Their isnt any whine and the filter looks clear. Will try the new fluid and get that replaced to see if that helps.

 

[Bob Lincoln]

Loose, slipping belt?

 

[lou4x2]

Its a brand new belt. Cars to go back to the main dealer in carlisle as my local Garage thinks I was sold a faulty pump. So still don't know till they have a look at it now just a waiting game