Okay buddy, we know the Blue Moon did not screw you up...

I would use the front pump from the second for the first, but.......... Since I rebuild these.

A)I would replace the B2 seal which is real easy to replace-16th picture-the black seal-and the orange seal...

How to Replace Your Oil Cooler Lines

To remove the plate(picture 11). Strattle it your hands around the outside, and push down with your thumbs, but you have to hit it the cover with a rubber mallet to break the seal. Then you push down with your thumbs to expose the ring, so you can pry it off-practice on the old tranny if you like...

Now if you pull off the B2 Piston which is the aluminum with the white seal, and you see the inner sleeve is metal, and not plastic behind the black seal... You really need to replace it as in the link above...

Ahh, inside is a dog bone, note the direction as one side will have one embossed stripe, and the the other end will have two or three ....Cannot put this sucker in backwards-put it in the way you took it out!!!

B) Now you can swap the pump like in the first two pictures of this link-Yes it is a 722.5 -722.3-722.5 is the same with the same part numbers...

722.5 transmission oil pump rebuid DIY - Mercedes-Benz Forum

Here is another wonderful picture process:

http://www.peachparts.com/shopforum/general-information/319957-722-315-pump-re-seal-pictures.html

Now I would stand up your transmission, so nothing falls forward inside which it can easily happen.. then you make matters a little worse...

I suggest you replace the outer paper like seal...

Now, and this is a big NOW... the biggest problem with these 722.3-722.5 is they will loose reverse, and it is all because of this stupid small lip-seal that gets brittle hard.., but these lip seals can be a challenge to put in with the lip pointing down in the direction you are inserting them, but what I have used to get a gaurentee placement is to use 3/4" to 1" wide gift wrapping ribbon, or even some 35mm film to place in between as you compress it like picture 5. Now the other problem. crushing the the teflon seals, and for that I clean the shaft, the groove, and the Teflon seals with alcohol, and apply Transmission assembly lube grease-This not petroleum wheel bearing grease as bearing grease can destroy the rubber seals. I think you should be okay with petroleum jelly, but the assembly lube will not melt as easy as the jelly. The Assembly lube is cheap.. like under ten bucks... The transmission assembly lube is to hold the parts together, so in this case you want to hold the teflon wrapped around the shaft because they can get destroyed on assembly...

Life Automotive Products Trans Prep Blue Transmission Assembly Lube | eBay

Now, I would replace the bushing too on the pump...

You are lucky son of gun... In Minneapolis is a "What Ever it takes"( they are in the city of(15 min to 30min away?) Arden Hills- it is WITTRANS.COM). You can get all these parts to this 722.3 and the lube. I cannot link the parts you need, but I have the service manuals, but you would have to PM me, so we can exchange emails, so I can email them to you...

Here is the wittrans location

Torque Converters Distributors Page - Consolidated Vehicle Converters, Remanufacturing Torque Converters for Automatic Transmissions

Here is a drawing of the transmission.

http://www.jpat.co.uk/59%20Mercedes%201B%20722.3%20722.4.pdf

Parts:

The B2 seal Job:

Part: 079 & 364

The swap of pumps Job:

Gasket 310 & 070

The decision to fix reverse, and replace pump bushing job?

310, 070, 034, 311, 2-179(get extras), 338, 339, get a new 879. Now you may have a 985 instead of the flat plate with dimples(like in the oil pump link), and sometimes you may find them cracked. Now, sometimes the PVC coupler can break and bend 985 or the plate with dimples, and I really suggest you get on of these to do the compressing-They are good to rebuild any Benz transmission....-Cheap too...

Transmission Clutch Remover Spring Compressor Kit | eBay

Now you, will need to clean the screw pockets of the pump and the bell housing well with swabs and denatured alcohol, and clean the bolt threads too. All of this so the thread locker grips, and the thread locker is the High-Temp/High vibration type(Not available at your auto parts store). You need LocTite 272. I do a three to four stage torque pattern, and go over by 20%-30% more as these pump bolts are too loose by my standards...

I would seriously replace the rear seal and nut, but the output yoke may have a seal on the inside of the yoke- Parts 074 & 798. The rear nut is a 12 point 30mm get it at Napa..

I made you dangerous, but it is your call...

Too much information

All the best,

Martin