1998 F-150, 5.4, 148,xxx miles, 4x4

I'm about at 150,000 miles and per the schedule my uncle had the truck on, it'll be due for the complete fluid changes.

Question(s):

First, what's the best thing to do when changing the transmission fluid? It has been done once already at like 75000 miles. Should I use a flush machine and just do the fluid or should I drop the pan, change the filter, and then drain the torque converter through the access hole? Transmissions in previous cars I've owned always seem to act screwy after I change the fluid/filter, so I'm a bit cautious about this truck.

Second, regarding the transfer case...Is there anything I need to be aware of when changing the TC fluid? I don't think it's been done the whole 150,000 miles. Synthetic or non? Etc...

Thanks for the input.

 

On the trans, considering it was changed at 75000, I would just go with the flush machine and 12 quarts of mercron V. The transfer case is pretty simple. Make sure you can get both of the plugs lose first and then drain it and fill it back up with Mercron V trans fluid till it starts to run out of the fill hole.

 

That brings to mind another question I had...The manual and the dipstick says to use Mercon. What's the difference between using Mercon and Mercon V?

 

mercron V is mercron. Its what ford says to put in most of their transmissions. There are a very select few trannys that take a special fluid.

 

MERCON is an old spec. THE NEW oil is MERCON V. This is a synthetic transmission fluid that has better heat resistance features than Dextron or Mercon. Your transmission and converter hold about 13 quarts. Pull the pan and clean it out. Get a new transmission filter for it. Wipe off the valve body above the pan. Wipe off as much crud as you can. Rotate the engine flywheel around with a 14 inch screw drive on the flywheel teeth. Stop when you see the converter drain plug. It looks something like a 1/8 inch pipe plug. Drain the other 8 quarts out of this plug. REinstall the plug with loctite. Fill the transmission with 13 quarts, startup and let it idle for 4-5 minutes while it fills the converter and level stabalizes. Your done! Flush is never a good idea as it can loosen deposits in the crevises and corners and cram it into a valve body spool.

 

Great explanation! Thanks! So use the Mercon V?

 

Absolutely. I did my 98 this way and the filter was stopped up, 170K never been changed. look at your stick closely, if it says MERCON V, then that is what is supposed to be in it. one thing I disagree with is I do not use loctite on the converter plug. Ford didnt, so why do you need to? I used to work in a transmission shop.............

 

My transmission dipstick just says 'Mercon', nothing else, that's why I was curious if I could use Mercon V

 

i think FORD says the plug is not reusable in the converter. It is suppose to be replaced each time and "locks" itself in place... I just put a couple drops of locktite on the old plug and reuse. It probalby will not fall out without, buy a could drops will guarantee it stays in. Its not that hard to break the bond when you need to remove.

 

So I've done some more research and talked to a few mechanics here at the Ford dealership and the info I've come away with is DO NOT USE ANYTHING BUT MERCON in the E4OD transmission. Mercon V might be compatible with Mercon, but the majority of the stuff I've heard and read leads to Mercon. I guess that's what I'll use...

And thanks for the info on the converter plug...I'll put some loctite on it. Blue or Red?

 

I used the mercron 5 in my 87 and 91 broncos with no problems. Mercron V is just a newer updated version of the regular mercron and can be used in trannys that were running regular mercron. Ive worked in a lincoln/mercury dealership for years and mercron V is all we used for 97% of the vehicles that rolled through the door.

 

Good to know. I always just used the old one with no locktite. Never had a problem, but I will now use the locktite.