Folks,

I'm gonna do a trans flush this weekend. I had gotten lots of good info about the proper way to do this earlier.

I am going to use the "pump out 4 quarts / refill 4 quarts technique" in order to thoroughly flush the trans.

My question is about the proper amount of trans fluid.

I checked with the parts place. The guy punched in my Exp model and said it took 10 quarts to completely flush. I figured I'd get a 12 case for good measure.

HOWEVER....in some previous reading....some folks reported 16 quarts. Does anyone know for sure?

This is for aN 98' 4x4 Exp. 4.0 Liter SOHC with a 5 speed automatic w/ overdrive. (Is the parts guy right when reporting 10 quart capacity?)

Also....it has gone a few K miles over the ideal change interval...I suspect it is gettting pretty dirty. Therefore, I am planning on chaning the filter and fluid with just a basic house brand fluid (Mercon V) and running it about 4 months or so to knock loose any crud......then change fluid and filter again...but the next time, put in Mobil 1 synthetic. Is this a worthwhile plan for a trans that is prolly a little dirtier than usual?

THANKS!

 

How many miles over have you gone? I would just have a mechanic properly flush your tranny with their equipment. That way, you know you have the right amount of fluid in and that it is all clean. You do NOT want to mix old and new fluid. I agree with wanting to save money by doing it yourself, but the tranny flush is worth the money spent. Good luck with whichever route you take.

 

Look at the "specifications & capacities" in your owners manual & also measure how much drains out & put that much back in. But like Brian sez it's worth the 70 or 80 bucks to have this done.

 

My 99 Explorer XLT 4WD 4.0 SHOC has the 5R55E 5-speed transmission. Owners manual says 10.3 quarts. After all said and done, I went through 16 quarts. I recommend having at least that on hand and return the extra if you don't need it.

I replaced with Valvoline VV360 Mercon V which is a direct replacement for the VV290 called DuraBlend. Valvoline tells me it is the exact same formula, just phasing out the DuraBlend name. I paid 3.70 a quart. It is a semi-synthetic. I think all Mercon V must be at least partially synthetic.

DO NOT USE MOBIL 1 FOR THE 5R55E TRANSMISSION! Mobil 1 is not rated for Mercon V according to their website. Amsoil and Redline have Mercon V rated synthetic fluids at $9 a quart.

I used the method of pumping out 2 quarts and then replacing it with two new. It was the simplest part of the job.

The 4WD components in my Explorer make it impossible to remove the tranny pan with removing either the catalytic converter or the FWD driveline. I opted to do neither and was still able to remove and replace the gasket and filter with the tranny pan suspended between the catalytic converter and driveline.

A word of warning: I found a website that said that while the tranny would pump the old fluid out via the cooler, it would suck new fluid in through the return from a bucket of new fluid. Sorry to say, this didn't work and it actually pumped old fluid into the new fluid!

So I went back to the pump 2, fill 2 routine. After going through 16 quarts, I had such clean fluid in my tranny that I could barely see it on the dip stick!

One other word of caution: The Motorcraft FT-134 transmission filter does not come with a gasket and most auto parts stores do not list gaskets only. If you get the Ford gasket at the dealer, it is $19 but has metal pellets to prevent over tightening and crushing the gasket. The Fel-Pro is $6 and does not have the special feature. Just make sure you get a gasket when ordering the filter if you get the Motorcraft filter.

 

Thanks for your write-up.
Can you tell me which cooler line it is that fluid goes INTO the radiator?

Here's my plan, tell me what you think.
I will mark off 4 gallon lines on the inside of a paint bucket. I will put a hose on the cooler line, start it up (put in Drive?), pour fresh fluid down the dipstick tube at the same rate as the old fills the paint bucket.

 

Just to follow up....I did finish......

I ended up disconnecting the front driveshaft at the front diff. It comes off in just a minute (ya gotta have a correct size Torx bit though...the little 6point-star bits).

That's pretty easy.

As far as one hose pumping out fluid and one sucking in....or just "gurggling" as some have reported......BOTH of mine pumped fluid OUT.

So....I had already dropped the pan and filter....and gotten about 4-5 quarts out. So...I just pumped out about 3 quarts/replaced 3 quarts (twice)....measured the total fluid that had come OUT of the tranny to make sure it was at least 10 quarts. I put a total of 10.5 quarts back in...just to be sure....drove about 10 miles checked the dipstick....and all seems well...so far.

Also....thanks for the info on Mobil 1 trans fluid. I thought it was rated for Mercon V for sure (being pure synth and all). Am surprised that it is not.

 

The ATF flows as follows: Out of the transmission, into the radiator (the same one as the coolant), out of the radiator into the secondary/external ATF radiator (if you have a secondary one), out of the ATF radiator back to the transmission. If you don't have a secondary, I highly recommed adding one. It is part of the tow package and might be part of the 4WD package. To find out which line on the coolant radiator is the output, just run the engine briefly with the bottom metal line disconnected and a hose attached to both the radiator and the metal line. ATF will shoot out letting you know the direction. Let the ATF out after the radiators so that you flush them, too.

Also, don't stop the flows at any point. There is not much pressure after the torque converter, but stopping or slowing the flow will blow seals and crack radiators. They aren't made to take pressure. Cracking the radiator will cause water to mix with your ATF and ruin your transmission.

Don't put it in "DRIVE". Fluid always flows even when in "PARK". That is why you check the fluid level while the motor is on and in park or neutral.

The ATF flows out at a relatively fast rate. You cannot get the fluid to flow into the fill tube as fast as it flows out.

Also to note: I checked the fluid level after I did the job and had to pump just a little out to make the level right. However, after driving about twenty miles, the level dropped below the hatch marks so I had to add a half a quart to bring it back up. I think that one quart will bring the level from the bottom of the hatch marks to the top of the hatch marks. The reason for the drop is probably due to a little air in the torque converter. I think I let the level drop too low once before stopping the engine to add. That is how I found out I cannot get it in as fast as it goes out! And that is why I recommend stopping after two quarts instead of four.

 

I just changed the fluid in a 94 Explorer using the DIY flush method. Diconnected one line at the radiator becuase they are easier to get to than the lines at the transmission. Mine had a radiator WTO cooler and an OEM air to oil cooler in front of the radiator. I added an extension to both hoses, aimed them into a bucket.

First I did pull the pan, inspect, clean and replace the filter.

With the hoses aimed at the bucket, I added 6 quarts, started the engine let it run until no more fluid would come out, then added 6 more, did it again. Reinstalled the cooler lines, tooped off the transmission with about 3 quarts.

By the way, the fluid was very clean, I understand that this method will get about 90% of the old fluid out. Fluid is cheap, abotu a $1 a quart, mine is an oder transmission requiring Mercon (not Mercon V), so the ATF was Chevron from Costco at about $13 a case.