transmission fluid advice

[Chip DeBruyckere]

Hey all,
2005 f150 5.4l 125,000 miles. About 6 months ago I noticed trans fluid was a bit low so I topped it off. Now I have the time and cash to do a fluid and filter change. My question is this, should I just do the 4 qrts and filter in the pan or pull the return line and drain and fill 4 qts at a time until all 14qts have been swapped out? I bought this truck used at 65k in 2009 and do not know if the fluid has ever been changed

Thanks

Topic

[Glenn]

Not all will agree… If you are willing to go the extra mile, I think pulling the return line and flushing the system until it runs clear is a good idea. It’s better with an attendant, so you don’t let the fluid run out (run dry) at any time during the process. That’s how I do my 100k transmission fluid changes. Let us know how it turns out…

[Chip DeBruyckere]

thanks for the reply, I think i am gonna try to swap out all the fluid. Im gonna attach a clear tube to the return line so I can sit in the drivers seat and see the line until it starts to bubble. The pan only hold 4 qts out of the 14 so I will only be able to pump out 4 qts of the old at a time.

[Glenn]

That might work. I’ve actually had two folks help with this procedure… I would have one person slowly and continuously pour TF into the transmission while another person cranks the vehicle. I would watch for the fluid color to change at the return line. The reason for the constant flow idea is to keep the torque converter well lubricated and also prevent foam (bubbles) from filling the system if it runs out and sucks unwanted air. The person in the vehicle shuts it off upon command when the color changes. That saves $ as the fluid is expensive. Anyways, it’s a good idea and will hopefully go well for you.

[Chip DeBruyckere]

Thanks, I ordered Castrol Merc V from amazon at 31$ for a case of 6 and bought 3 cases. They should be here monday so I will update when all is said and done.

[Nick Warner]

Make sure you aren’t just using regular ATF when you do this. It should take Mercon LV if I recall. For sure check the owner’s manual for it. The factory Motorcraft fluid isn’t really out of line as far as price goes. If you wanted to upgrade to a synthetic like Royal Purple or something you need to make sure it meets that spec.

[Chip DeBruyckere]

newer ford transmissions use LV i believe, but the 04-08’s still used Mercon V. Castrol has meet all requirements to label their product mercon V. Many ATF’s are universal and simple stay the meet or exceed ford specifications. Plus the difference between castrol and motorcraft was significant enough across 14 qts to matter and i know many f150′;s running the castrol

[Nick Warner]

I missed the post where you mentioned using the Castrol. I’ve seen people dump the cheapo Dex/Merc into everything and do major damage so I figured I would mention it. The Castrol stuff should be fine.

[Chip DeBruyckere]

Just finished changing out brake fluid, PS fluid, t-case fluid, and trans fluid. PS was very very dark, so wasnt brake fluid. Used Preston DOT 3 and Merc V in PS. T case drained ~4.5 qts and it was still pretty red and didnt smell burnt or look gritty. This was my first time ever changing it. It only is supposed to hold 2 qts so i think my rear trans seal is leaking. For the transmission I attached 10ft of vinyl clear tube (3/8ID) to return line and started engine. Measured out 4 qts and stopped. Now pan is empty so I dropped it and replaced filter and cleaned magnet. Magnet was only a little fuzzy and pan had no debris in it. I found the factory dipstick plug still in there which means this was the first time the fluid has ever been changed. The fluid was very dark but you could still make out that it was red. I honestly expected there to be much more debris in pan seeing as there is 126k on this fluid and i use my truck for towing and hauling. gasket was reusable so i just cleaned everything up and bolted pan back up after replacing filter with new motorcraft one. Added 4 qts new castrol merc V then started engine and drained out 4 more qts. added 4 qts and then drained 4 qts. Added 4 more drained 2 then added 1.5. put the return line back in place and took the truck for a spin.

Results:
Brakes feel 10x more firm
PS feels smoother
Transmission shifts and accelerates like brand new. Even the bump when putting it into D is gone.

I will check transmission level over the next week and top off as needed. Have 1.5 qts on hand in tool box

[Ingvar]

It’s post factum, but does your pan actually have drain plug? As when it does, the safest way to drain ENTIRE ATF out is to drain whatever needs to be drained, refill with proper volume, drive for about 15 miles, drain and refill again, and do so, untill you have ENTIRE fluid replaced. As you have fluid stored in many pockets – trannie, lines, torque converter, ATF radiator. I am not even sure how you managed to get fluid out by simply starting the engine, as you have to have gear engaged to use ATF pump to circulate the fluid.
What you do by driving on ATF is “natural” power trannie flush. Without disturbing any lines and taking chances on dam start leaking.

[Chip DeBruyckere]

Unfortunately Ford stopped putting drain plugs on the transmissions an torque converters in these trucks. After swapping out 8 qts I stood on brake and cycled the gears in an attempt to push fluid through their areas of valve body. By disconnecting the cooler return line and starting the engine, the transmission pumps the clean fluid from the pan,pushes it through the the transmission, through through the cooler and then out the return line into a bucket. As the new fluid is sucked up in the pan it it pushing the old though the system into a bucket. If I had a drain plug, I would have done it the way u suggested after replacing filter. So far no leaks, if I do get any, then I guess ill just have to replace the lines. I like to think of repairs as a great way to learn new things, that way they don’t become cumbersome

[Author]

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