Is there any issue using the same fluid pump for filling the trans and the rear diff or should I buy one for each? perhaps a pump clearing the previous fluid w/ the new fluid would be enough?

Can these be stored to be re-used? Best way?

I'm planning on using Honda trans fluid and mobil1 75w90 LS, any issues?

 

I used the same one for both.

Just run the 2nd fluid through the pump a bit to clean it out and you should be ok. Whatever is left and gets in will be so diluted it don't affect anything.

 

I went through this a couple of months ago. For the trans., buy about 4 feet of heater hose and thread it into the engine bay, insert a funnel and your done in 5minutes. I did use a pump for the rear end and what a mess that turned out to be. If you do use a pump, be very patient and pump slowly or the pressure will cause the tubing to seperate which is the problem I had and the resulting mess. Next time I'm going to use a large rubber bulb syringe for this task.

Edit "1/2in heater hose