Changing to synthetic?

[Stelth]

I just got an old ('97) F-150 with a new 4r70w transmission. I'm not sure if I can get any details about the rebuild, but I can tell you that the fluid is clean, pink, and sweet-smelling. I'd like this trans. to last as long as possible, so I'm thinking of using Amalie Universal Synthetic ATF. Both the Amalie and Mobil 1 ATF's claim to be compatible with a lot of ATF's including both Mercon and Mercon V.

From what I've been reading, you shouldn't mix Mercon and Mercon V, but it looks like these synthetics would mix with either.

Would it be OK to do several pan-drop or evacuation changes in a row to try to clean out the old fluid, or do I need to do something to try to change it all at once?

 

[Astro14]

Why not a flush?

You can flush it yourself using the cooler line.

Quickly: Drain the pan and refill with fresh fluid. Now, disconnect the pressure line for the cooler, attach a hose, put the hose in graduated clear container. Start the engine, idle it until you've pumped out 2 Qts. Shut the engine off, add 2 Qts to the trans. Repeat until you've completely flushed out the old fluid. You can even shift through the gears while idling to ensure that every circuit is flushed.

You're using the transmission pump to run the fresh fluid through...up to you on your choice of appropriate fluid... I don't know the capacity on this one...but you'll clear it all out this way.

 

[MetalSlug]

Just drop pan and filter change, that all u ever need.

 

[hate2work]

I agree with Astro, take the time to do a flush. At 97k, the rig deserves it

 

[qdeezie]

Regarding the transmission type in this vehicle, you have a few points where you can drain the fluid.

Drain Point #1 - Transmission Pan.
This is the most obvious place to drain your fluid and no further explanation is needed here.

Drain Point #2 - Torque Converter.
There should be a rubber plug at the bottom of the bellhousing where this resides. You will have to remove this rubber plug and rotate the engine by hand until the torque converter drain plug is visible. Once this is visible, you can unscrew and drain the fluid out of the torque converter. This process is much like an oil pan drain plug.

Drain Point #3 - Fluid Lines (Optional, but this is what I do.)
If you can easily access and unscrew the 2 fluid lines on the transmission, mark one of the lines and the place on the transmission where it goes so you don't cross them up and unscrew both lines and blow the fluid out with compressed air. This will remove the fluid from the lines and radiator.

Regarding fluids being mixed, you should be able to do so and the label on both bottles should indicate that this is in fact true. Using all three methods above on your truck, you should be able to get at least a good 95% or more of the old fluid out. Since the transmission is new, the fluid should be new and since you're going with synthetic, you should be good to go moving forward.