newbie here, i need a couple answers please
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Junior Member
Joined: Oct 2015
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newbie here, i need a couple answers please
i purchased for my son a ford f150 heritage 2004, 4x2, 6 cyl 4.2 engine.
it has now 132000 miles.
i dont know if this truck have got a rear differential manteinence yet, anyway im going to drain the old fluid and fill with new oil.
acording the small metal tags in the differential, it requieres 75-90w gear oil; i went to the ford dealer to purchass the oil and they said they dont carry that anymore, they said that the oil they have its motorcraft 75-140w, so, my question is:
whats the difference between 75-90 vs 75-140
can i use 75-140? its an old truck.
or should i search and buy 75-90W?
we live in south florida(just mention if weather has anithing to do)
thanks in advance.
it has now 132000 miles.
i dont know if this truck have got a rear differential manteinence yet, anyway im going to drain the old fluid and fill with new oil.
acording the small metal tags in the differential, it requieres 75-90w gear oil; i went to the ford dealer to purchass the oil and they said they dont carry that anymore, they said that the oil they have its motorcraft 75-140w, so, my question is:
whats the difference between 75-90 vs 75-140
can i use 75-140? its an old truck.
or should i search and buy 75-90W?
we live in south florida(just mention if weather has anithing to do)
thanks in advance.
Senior Member
Joined: Mar 2001
Posts: 4,506
Likes: 6
From: Puyallup, WA
That's odd that they don't have the 75-90, because that's what's spec'd for the front axle on 4x4's..
I had a 97 with the 5.4 in it which had the 9.75" rear end and it was spec'd for the 75-140 from the get go.
If I recall, I think Ford switched the spec for all rear ends to be 75-140..
They also said that my old 5.4 could use 5w20 oil... I never switched to that and just used 5w30 the whole time and it had 255,000 miles on it when I traded it and it was running great.
I did a couple of rear gear lube changes over the years and used Amsoil 75-140 and Royal Purple 75-140, but always got the Ford friction modifier to add to it, even tho the oils above said they already had it... Never had a problem with the LS on the rear end.
I'd just use 75-140 in the rear end for your 04 and call it good.
Good luck!
Mitch
I had a 97 with the 5.4 in it which had the 9.75" rear end and it was spec'd for the 75-140 from the get go.
If I recall, I think Ford switched the spec for all rear ends to be 75-140..
They also said that my old 5.4 could use 5w20 oil... I never switched to that and just used 5w30 the whole time and it had 255,000 miles on it when I traded it and it was running great.
I did a couple of rear gear lube changes over the years and used Amsoil 75-140 and Royal Purple 75-140, but always got the Ford friction modifier to add to it, even tho the oils above said they already had it... Never had a problem with the LS on the rear end.
I'd just use 75-140 in the rear end for your 04 and call it good.
Good luck!
Mitch
Senior Member
Joined: Dec 2006
Posts: 43,542
Likes: 819
From: Joplin MO
Use 75w140 full synthetic. If it has a limited slip rear you also need friction modifier. You don't need to buy the lube from Ford, but you will have to go to Ford for friction modifier if you need it.
I recommend you get a gasket for the rear cover, the factory uses RTV instead of a gasket. Autozone has gaskets.
I recommend you get a gasket for the rear cover, the factory uses RTV instead of a gasket. Autozone has gaskets.
Senior Member
Joined: Jan 2002
Posts: 5,994
Likes: 221
From: Wilmington,NC
You can buy 75-90 at any auto parts store and probably Walmart. I wouldn't buy lube from ford because you will pay a lot more for the same stuff. And if it needs friction modifier that can be bought at an auto parts store too or buy the rear lube that has it already in the lube. I recently put new 75-140 in the 9.75" rear of my truck. I bought Valvoline that already had the FM in it from Autozone. The traction lock works great afterwards. My truck has 134k miles on it.
