changing gear oil?
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notchback
Founding Member
90 weight synthetic
pull the diffy cover, it will all drain out
then replace it w/ a new gasket, and fill it up to the fill hole
pull the diffy cover, it will all drain out
then replace it w/ a new gasket, and fill it up to the fill hole
beaver2489
Founding Member
what he said 
the plug where you refill the diferential is on the driver side of pumpkin, I think you take a 3/8 or 1/2 ratchet and it plugs into the refill plug and you just unscrew it. buy one of those gear oil pumps. it screws onto the bottle of gear oil, put the hose from it into the refill hole of differential and pump away. rear end work is damn messy. remember to get some of that friction addative also. you can see the plug here I think
the plug where you refill the diferential is on the driver side of pumpkin, I think you take a 3/8 or 1/2 ratchet and it plugs into the refill plug and you just unscrew it. buy one of those gear oil pumps. it screws onto the bottle of gear oil, put the hose from it into the refill hole of differential and pump away. rear end work is damn messy. remember to get some of that friction addative also. you can see the plug here I think
beaver2489
Founding Member
Its been awhile since I put gears in my car. I'll look up the name of the friction addative. also I used some of the orange ATV sealant to make the diff. cover gasket. seriously get one of those gear oil pumps to help refill. One cost me like $2-4; a lot less messier. brb I'll find the friction add.
beaver2489
Founding Member
http://store.summitracing.com/default.asp?target=egnsearch.asp&autoview=sku&N=300629 <---friction mod.
and heres a picture of one of those gear oil hand pumps, I got one a walmart a year ago back with the oil. I used 3 bottles 90W I believe wich I got from ol'Walmart too lol. and its RTV not ATV sealant sorry. heres and example of the hand pump
and heres a picture of one of those gear oil hand pumps, I got one a walmart a year ago back with the oil. I used 3 bottles 90W I believe wich I got from ol'Walmart too lol. and its RTV not ATV sealant sorry. heres and example of the hand pump
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basic 80-90 gear oil will do fine. the friction modifier can be bought at a ford dealer for like $5. when you drain the housing, just take out the bolts on the bottom, and loosen the ones on the top. pry the bottom slowly, try not to get it every where cause gear oil is smelly and nasty. you can use either a new gasket or RTV or use both. i just used a gasket cause i hate scrapin that stuff off. if you have the stock cover you will need to buy three quarts of oil, but you will only use about 2/3's of the last bottle. that pic above is a 9" rear, not the same but if gives you a general idea as to what to look for.
beaver2489
Founding Member
also, if you use the pump. I put in 1/2 of the 1st bottle of gear oil, then poured the friction modifier into the 1/2 full bottle of gear oil and screwed the pump back on & pumped it all in. ya, I don't think it takes all 3 bottles. just remember to add the friction mod to the gear oil before you fill it all the way up. its a real messy job man. rear end oil (especially the funky old oil) smells bad. you can wash your shirt a few times and still smell it lol
maverick0716
Founding Member
beaver2489
Founding Member
lol nothing better than some butt grease to freshen the roomHISSIN50 said:This can be modified by a change in diet.
TRWXXA
Member
I just did this last week.
Just like it's been said already... Remove all the cover bolts except the top 2 or 3. Just loosen those. Pry the bottom of the cover away from the housing with a screwdriver. The old oil is going to pour out everywhere, so have a large, deep pan (like a cat's litter box) to catch it in.
If you have the car jacked up at the rear only, you'll still have some old oil left in the housing. You'll need to scrape it out of the housing by hand. Don't do it with a bare hand. There may be small, sharp bits of metal in the bottom, so use a scraper of some kind, or use a lint free cloth.
Closely inspect the gears, and look for excessive wear and/or chipped teeth.
If you need new axle bearings or seals, now is the time to do those since it'll just take a few minutes to remove the axles. They're cheap and easy to do, but require some special tools that can be borrowed from AutoZone.
Clean the old sealant or gasket material off the housing and cover with some brake parts cleaner and a putty knife.
Using RTV sealant is recommended instead of a gasket. Run a bead of it around the surface on the housing, making sure you run it to the inside of the cover bolt holes. Put the cover in place and put in the bolts, tightening them in a "star pattern", like you would lug nuts. Do not tighten them too much or you may distort the cover, causing a leak. Let the RTV dry for at least 6 hours.
Find the filler plug on the driver's side of the housing and remove it. You'll need a 3/8" ratchet, and probably a 3" extension to reach it. It does not require any socket.
Just under 2 quarts of 80W-95 gear lube (or 75W-140 synthetic), and a 4 oz. bottle of friction modifier will be needed to fill it (stock size cover).
Use a pump as suggested to put the 1st quart in, then put in the modifier. The Motocraft friction modifier comes with a small spout to help you put it in the filler port. Be careful not to spill the modifier or get it on you -- IT STINKS LIKE YOU WOULDN"T BELIEVE!!!!!
Start adding the second quart with the pump until you can feel the fluid level at the bottom of the filler port (or it starts to pour out onto the floor). Replace the plug. My stock rear end took exactly 2 quarts. Since I added the bottle of friction modifier, I was left with 4 ozs. of gear oil left in the 2nd bottle of lube.
Lower the car, and drive it like you stole it.
Just like it's been said already... Remove all the cover bolts except the top 2 or 3. Just loosen those. Pry the bottom of the cover away from the housing with a screwdriver. The old oil is going to pour out everywhere, so have a large, deep pan (like a cat's litter box) to catch it in.
If you have the car jacked up at the rear only, you'll still have some old oil left in the housing. You'll need to scrape it out of the housing by hand. Don't do it with a bare hand. There may be small, sharp bits of metal in the bottom, so use a scraper of some kind, or use a lint free cloth.
Closely inspect the gears, and look for excessive wear and/or chipped teeth.
If you need new axle bearings or seals, now is the time to do those since it'll just take a few minutes to remove the axles. They're cheap and easy to do, but require some special tools that can be borrowed from AutoZone.
Clean the old sealant or gasket material off the housing and cover with some brake parts cleaner and a putty knife.
Using RTV sealant is recommended instead of a gasket. Run a bead of it around the surface on the housing, making sure you run it to the inside of the cover bolt holes. Put the cover in place and put in the bolts, tightening them in a "star pattern", like you would lug nuts. Do not tighten them too much or you may distort the cover, causing a leak. Let the RTV dry for at least 6 hours.
Find the filler plug on the driver's side of the housing and remove it. You'll need a 3/8" ratchet, and probably a 3" extension to reach it. It does not require any socket.
Just under 2 quarts of 80W-95 gear lube (or 75W-140 synthetic), and a 4 oz. bottle of friction modifier will be needed to fill it (stock size cover).
Use a pump as suggested to put the 1st quart in, then put in the modifier. The Motocraft friction modifier comes with a small spout to help you put it in the filler port. Be careful not to spill the modifier or get it on you -- IT STINKS LIKE YOU WOULDN"T BELIEVE!!!!!
Start adding the second quart with the pump until you can feel the fluid level at the bottom of the filler port (or it starts to pour out onto the floor). Replace the plug. My stock rear end took exactly 2 quarts. Since I added the bottle of friction modifier, I was left with 4 ozs. of gear oil left in the 2nd bottle of lube.
Lower the car, and drive it like you stole it.
beaver2489
Founding Member
I'm tired and have been drinking, but is it called ATV or RTV sealant? sorry for pointless post
great description of how to do the job BTW trwxxa
great description of how to do the job BTW trwxxa
TRWXXA
Member
beaver2489 said:
You're right of course. It is RTV sealant.
It didn't look right when I typed it, but I kept going. I too am tired, and I've also been drinking (I'm on vacation this week).
I've edited the post to correct my brain fart.
Michael Yount
Mustang Master
It's VERY doubtful that changing the gear oil is gonna do anything to quiet a whining/noisy rear end. Instead of going to the time/trouble of changing the fluid, you'd be better off directing that money towards having someone with differential experience diagnose the problem and repair it for you. Sounds like it's time for a rear end overhaul. So, what gears did you want to replace those 3.08's with? 
Old gear oil stinks like nasty bad. DON'T get it on your clothes or they will forever smell of gear oil. Wear junky clothes and I'd suggest latex gloves too.
One other thing. I've never heard of changingthe oil to quiet down a winey set of gears. It may not be the solution to the noise. You may be low on fluid. Rear gear oil doesn't go bad.
One other thing. I've never heard of changingthe oil to quiet down a winey set of gears. It may not be the solution to the noise. You may be low on fluid. Rear gear oil doesn't go bad.
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