Howdy fellas! Well when I go home for the 96 coming up for the fourth of July I want to change out the diff fluid (has been submerged etc. needs to be done!!!) I have an 8.8 with a 3.73 LS and really need to change the diff fluid. How hard is it to do, what do I need, and how much time will this take? I really want to kill as little time on the truck as possible this 96 as I have not seen either my fiancee or my family in 2 months, so let me know if it would be worth it to just have the dealership do it when they do my inspection! thanks a lot!
~Phil
"Semper Fi"

 

http://www.mobiloil.com/USA-English/..._Oil.aspx?pg=2






LEVEL 1 WRENCHACULTY

meaning even I could do it.

 

Except ours don't have a drain bolt. You have to take of the cover. Also use the right fluid to fill. Owners manual may say 75W90, but Ford has changed it's specs to 75W140. Also with LS you will need a bottle of friction modifier.

 

Cool! Thanks guys, should be an easy do...do the bottles for diff fluid already come with a pump or what would I use for that? Also any recommendations on fluids, personal pref's? Thanks again guys! How much would I need? I can't get at my owners manual right now lol, the truck is in a storage unit off-base. Will it tell me what all the bolts need to be torqued down too? Do I have to jack up the rear end so there is no pressure of the tires on the deck or anything like that? Thanks again guys!
~Phil
"Semper Fi"

 

Hey Phil,

A rear diff fluid change is a pretty easy job. You don't need to jack the rear or take the weight off of the tires, and you shouldn't need a pump or suction gun. The bottles of Motorcraft 75W140 have a funnel shaped tip and you can angle them into the fill plug on the front side of the diff to refill it.

You'll need three quarts and you'll have some leftover. You'll also need a bottle of LS lube/friction modifier. The Motorcraft 75W140 is expensive, something like $15/quart, but that's the stuff you want to use.

There's no gasket on the rear diff cover, so clean up the mating surfaces throughly without gouging them, giving them a final wipe with a rag sprayed with brake cleaner. Then put a bead of black RTV (or the official Motorcraft stuff, see below) on and let it skin over for the required time. (10 minutes maybe?)

Bolt it back up, tightening in a star pattern to the specified torque and you should have no troubles. I read that allowing time for the sealant to skin over is key to getting a good seal. I don't know if that's true or not. I did it and mine has held tight with no drips or seepage for over a year and 12k miles.

You can get the factory-recommended sealant from the dealer. This thread shows a pic of the official Motorcraft sealant: https://www.f150online.com/forums/sho...d.php?t=276840

A diagram of the cover, sealant bead, and torque specs are here: http://www.supermotors.net/vehicles/...y/media/185332

And there's a writeup on the rear fluid change here http://www.fordf150.net/howto/differentialfluid.php with some pictures. (Though this one uses a gasket and 75W90, which you don't want to use.)

~Ed

 

Easy easy easy. Use Royal Purple ($11-12/qt) and you wont need a Friction Modifier. Almost as easy as changing your oil, just a few more bolts. Remove the old cover, let it drain for a few minutes. Scrape all of the old gasket maker off. Put new RTV sealant on the diff cover. Use a solid bead around the cover and then go back and go around every bolt hole. Put each bolt in by hand, then torque each bolt down to the required torque. I did a star pattern like you would on the wheels. Let the RTV set up for a few minutes, then fill the diff with fluid. I found it easy to put a short length of tube on the tip of the bottle, then put the tube in the diff. At least that was easier on the rear axle. Shouldn't take more than 30 mins. I was nervous as hell my first time, but did it with no problems, and most importantly, NO LEAKS

 

Outstanding! Thank you very much fellas! Now I just gotta wait for the 96 coming up! WOHOO! I can't wait to get this trash done w/ I'll probably do it before the truck gets put up for the night, so the seal has time to set. I'll also do the 300 mile check to make sure all is still well. I can't wait, should be fun!
~Phil
"Semper Fi"

 

Honestly, the seal doesn't take that long to set up. I let mine sit for no more than 10 mins (basically forgot to let it sit) and started filling it up. Almost a week later and zero leaks.

 

Good to know that it will seal that fast, but I go by what I was taught, and thats do it once, and do it overkill lol. I dunno I'd rather do over-kill than do it wrong. Thanks again for all the help!
~Phil
"Semper Fi"

 

Whoops. I cut-n-pasted a couple of those links from another post and didn't check 'em.

These will work better:

A diagram of the cover, sealant bead, and torque specs are here:
http://www.supermotors.net/vehicles/...y/media/185332

This thread shows a pic of the official Motorcraft sealant:
https://www.f150online.com/forums/sh...d.php?t=276840



Ed

 

That retails for $20... Get the $5 stuff from the auto parts store. It'll work just as well.

 

Yep. I used "Versachem automotive black RTV type 270" that I found in the toolbox. It has pics of an oil pan and a diff cover right on the package. Worked fine for me, but others here swear by the Motorcraft stuff.

Maybe it's the *same* stuff in a different tube!

 

LOL Most defiantly the same stuff in a different tube, the only actual thing I will buy motorcraft is the Oil Filter (and other various parts that were BUILT for the motor) other than that I go After Market gear. Thanks so much for the input guys, getting me excited to go home!
~Phil
"Semper Fi"

 

Yeah, and I accidentally ended up buying the Motorcraft sealant. Tricky parts guy (not my normal guy, but still knows me) snuck it in my order (2008 diff cover). $15 even after the discount I get...

 

That sucks! What a rip, I definately am going to get a nice brand, but i'm not paying 15 bucks for sealant. No dice! lol I need to get a Mag-Tech pan, just have an income problem (girlfriends B-day in July) so there goes 2 months pay haha lol. Its going to be hard to balance this 96, I have 800$ in parts sitting at home waiting to get installed, and I gotta do an oil change and diff-change, and legalize my window-tint (gotten 6 different warnings lol, can't use the USMC excuse too much longer i'm gonna get it if they look in my center console and find out i have gotten lucky all that time) get it inspected, and do a complete detail...and my lady hasn't seen me in 6 weeks hmmm...I gotta figure out how to balance this act haha
~Phil
"Semper Fi"