Hello everyone, I go back to his wisdom and knowledge to help me solve some problems. My FX4, 2007 has 64,000 miles and, through an oversight does not change the transmission oil. I have read some post and I have consulted several specialized mechanical; of all, few have recommended me to run the oil change. The other tells me that, since the internal parts are worn and the new oil, having higher viscosity, began to slide the discs. It may make sense but when I see the oil, this slightly dark and has no odor. There is a check valve that regulates the oil flow to the refrigerator installed in the front to keep the temperature not so high. I need to please all of you who have great experience with it please help me. I take the question to the following: As I have a 3.73 ratio differential and OEM 315/70R17 tires, I will replace and install ratio 4.56. I use a friction enhancer in both differentials: front and rear? What do you recommend. Thanks and greetings to all.

 

Change the fluid. Use a fluid exchange machine to get it all out, simply dropping the pan gets less than half the fluid out.

Only the rear axle needs friction modifier, and that's only if it's limited slip.

 

^x2. But if you want to really be thorough you can drop the pan too and replace the filter after you flush the system.

 

There is a chance that a transmission with high mileage will slip after an oil change. It will depend on how much wear there is on the transmission. I flushed the transmission on my wife's Toyota with 70k miles and had no problems whatsoever

 

Absolutely, positively change the fluid. Use only REAL Mercon V or a full synthetic like Mobil 1 ATF. Don't let anyone talk you into believing that an additive makes Dex 3 the same as Mercon V. Use ONLY Mercon V or full synthetic.

I am about half thinking that you should change the filter. It's probably ok since you aren't having any problems, but I always change them on anything I work on.

Darrin

 

Thank you all, actually, I am determined to change the oil in my transmission, I do not think anything bad will happen, in contrast, will be positive and can extend the useful life thereof. Not applying an additive to the transmission but if we used a good synthetic oil. Referring to the breeder of friction for the rear differencial, providing or much should I add? . If I'm not wrong is a little over four quarters ,What is the best brand that you recommend?

 

Any brand of full synthetic 75W-140 oil is fine for the rear differential. The front differential takes 80W-90 conventional oil, but you may use synthetic 75W-90. If the rear is limited slip, use 4 ounces of friction modifier that meets Ford specifications.

 

if you are doing the fluid yourself, drop the pan, remove the filter and lower the valve body, you will get 80% of the fluid out that way.

 

That doesn't drain the converter - I don't see how you can get 80% out that way - please elaborate?

 

Regarding the brand of LS additive, I'd recommend using only the additive from Ford.

A couple years ago I changed the fluid in the rear end of my wife's 02 explorer (8.8 LS). I used an additive that supposedly "met Ford specifications", but after a couple months the rear end started chattering around corners. I changed the fluid again and this time added the additive from Ford. The chattering cleared up almost immediately.

 

Good point, but there may be an availability issue in this person's home country. As I remember, he uses a translator and is not in the US or Canada.

 

Ok, I finally decided to make the change the oil in my transmission, use CASTROL MERCON V, remove the lid, remove the strainer, remove the valve, disconnect the lines to the heat exchanger, and pull the torque converter according a procedure that you sent me. The result, changes are needed, the blow had when changing 2nd to 1st speed I have not heard again in short, a success, thank you all for the help they gave me, from now on, pending'll change the oil every 30,000 km

 

9 3/4" rear ends in owners manuals under fluid specs state add 8 ozs of modifier

 

The 8.8" & 9.75" takes 4 oz

The 10.25" takes 8 oz

MGD

 

My 97 had a plug in the converter, will my new 07 5.4 HD edition have this plug?