Changing trans fluid to synthetic

[early99psd]

I have an e99 and was wondering I need to service my trans and was thinking of switching to synthetic. Is there any thing I need to do to flush out the reg fluid, or just drain and fill with the other?


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[E-Man]

Originally Posted by early99psd

I have an e99 and was wondering I need to service my trans and was thinking of switching to synthetic. Is there any thing I need to do to flush out the reg fluid, or just drain and fill with the other?


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If you drain the pan and converter I believe you will only be able to drain about 8 quarts. I think the entire trans holds a little over 17 quarts. I had my Ford dealer flush my trans a few weeks ago and refill it with synthetic Schaeffer's All Trans that I brought to them. Some people will say you shouldn't run Schaeffer's in a stock 4r100, but Schaeffer's guaranteed me that it is safe for a stock transmission. My truck runs great on it and the fluid change alone lowered my trans temps around 10 degrees.

[early99psd]

That's what I was thinking, that I needed to flush it.


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[04sblightning]

Whats the difference between a flush and drain? Other than more fluid.

[early99psd]

Your right I just did not want to mix the different fluids


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[rufushusky]

Originally Posted by 04sblightning

Whats the difference between a flush and drain? Other than more fluid.

In a flush fluid is forced through the trans, you need to be careful cause too much pressure can tear stuff up.

I used this method...gets about 95% of it out.

4R100/E4OD Trans Flush Procedure - PowerStrokeNation : Ford Powerstroke Diesel Forum

Worked like a charm.

[jesilvas]

Not all flushes force fluid out. Wynn's machines use the transmission to pump it all out. As the fluid is pumped out it spins a turbine and shaft like a turbo does which pulls fluid out of a reservoir and refills the fluid at the same rate it's pumped out.

[rufushusky]

Originally Posted by jesilvas

Not all flushes force fluid out. Wynn's machines use the transmission to pump it all out. As the fluid is pumped out it spins a turbine and shaft like a turbo does which pulls fluid out of a reservoir and refills the fluid at the same rate it's pumped out.

Very true, I should have mentioned that!

A shop by me has the heated one for the 5r110s. Pretty cool machine.

[jesilvas]

I tried one for the 5Rs. It took forever
Wynn's are the only one's I've used and are the correct machine for the job.