This is on my 97 F150 XLT 4x4 extended cab with the 4.6 automatic.

1)
Going to change the rear end fluid and the front diff fluid as well.
Just want to verify the fluid type/weight.

Front: 75W90 GL5 Gear Lube (3.6 quarts)
Rear: 75W140 GL5 Gear Lube (5.5-6.9 quarts)

Now is ther anything better than that or stick with those?
Redline or Royal purple?

Also you do not add friction addiditive stuff correct?
Can I drop the cover on both or is it easier to just use the fill/drain plugs?


2)
I'm looking at replacing the plug wires. Jegs has Fordracing ones I think 9mm for 75 bucks, is it worth it compared to the normal $40 at local parts stores? The plugs are motorcraft and have been changed a few months ago. No mods on the truck besides 2nd cats removed with flowmaster.Eventually will put a cold air intake on (maybe).
I guess I'm debating rather or not the extra cash is worth it or not. Thoughts?

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I went with Royal Purple, in mine. An the additive (modifier) only matters, if your running a limited slip. You'll need the modifier, so the limited slip won't bind up. I got Auburn's agressive Positrac gear differential, an man did that thing require ALOT of modifier! An drop the cover. Easier!

As far as the wires. I went Performance Distributors wires. They're call Livewires. Might be more then what ya wanna pay. But, they are freaking awesome! Each wire is numbered, comes in colors, 10mm, an are sleeved! Here's the link, if your interested!

http://www.performancedistributors.com/97f150.htm

 

Thanks for the response. As for Limited slip diff in the back, not sure if it came with one or not. I certainly dont think the previous owner put one in.

Is there an easy way to tell by looking at it.


For plugs, you are right, I'm not going to fork out that much for wires. At most I'd get the fordracing ones.

 

Their should be a metal tag, hanging from one of the bolts. It'll have a number on it. Post it up here, an we'll see what ya got. OR, look at your driver side door jamb. I'm pretty sure there's a axle code on their!

My rear diff., isn't stock. I put that in, it didn't come with the truck new.

Ford Racing, Accell, etc. Make good wires. Go with 8-9 mm wires!

 

Look on the door sticker. If the code for the rear axle is a letter and a number (ex. H9), it is a limited slip and you need the friction modifier. If 2 numbers, (ex. 19) it is an open diff, no modifier.

 

yeah check the door for limited slip and when changing it, I would take off the cover (never hurts to check everything)