Why does my 2004 dodge ram 1500 have a p0129 code?

Compare, or check with the parts makers for compatibility lists. They often say fits 'x, y, z models. Rock Auto is a great website for this
https://www.rockauto.com/en/catalog/dodge,2004,ram+1500+pickup,4.7l+v8,1424629,steering,power+steering+pump,7380

https://www.google.com/search?q=2001+Dodge+Ram+1500+5.2+power+steering+pump

They look different

https://www.google.com/search?q=2004+Dodge+Ram+1500+4.7+power+steering+pump

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transmission system malfunction can be a few things the following links give some examples of different problems associated with p0700 code but more than likely if their is a noticeable problem than may have to have it diagnosed by a transmission shop
P0700 Transmission Control System Malfunction P0700 Dogge Ram Yahoo Video Search Results 2005 Dodge Ram 1500 transmission codes p0700 p0841 Transmission Automatic...

• egr valve
• egr sensor
• cam shaft sensor
• barometric pressure sensor (map sensor)

vacuum leak somewhere, out of time, broken timing belt or missing teeth.

code p0129 refers to barometric pressure-two low===causes wiring---BARO sensor, ---mechanical fault
code p0441 refers to evaporative emission (EVAP) system--incorrect flow detected=== causes ---hose connection/s---intake leak--EVAP canister purge valve

replace the BARO sensor and the purge valve after seeing that the filler cap is on correctly.

Here is the link to view the serpentine belt diagram for 4.7 Dodge Ram 1500: https://serpentinebelthq.com/2004-dodge-ram-1500-slt-4-7l-serpentine-belt-diagram/

P0340 is for camshaft position sensor circuit malfunction so the problem can be in you hav already changed sensor, then you need to check wiring from sensor to ecu and if the wires are ok than check the ecu! It can be either of them cousing the problem.

took valve body down , saw 6 selenoids is telling me to change D selenoid, with is d selenoid

You need to replace the o2 senser that comes off the rihgt side of the truck.

P0129 Barometric Pressure To Low

the transfer pump is going bad ...dodge has an intank replacement for your vehicle