2005 Grand Marquis, what weight gear oil works best in these things? I can't remember the last time I owned a rear wheel drive car.
Grand Marquis Gear Oil?
- Thread starter Johnny
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Whay does the owners manual recommend? I would look up the viscosity at the Amsoil web site. Then buy some Amsoil unless you want to run DELO ESI gearlube.
From Crownvic.net
Rear Axle:
Capacity:
-02: ~3.75 pints
03+: ~5.0 pints
Service refill capacities are determined by filling axle 1/4 inch to 9/16 inch below bottom of filler hole. Vehicle must be level with ground.
75w140 is spec'ed for the rear axle bearing TSB kit, and factory fill for Limo and now Police applications. Most use 75w140 when changing the differential fluid
80w90 was factory fill for most years
Traction-lok axles also require 4oz of Motorcraft XL-3 friction modifier
I plan on putting Amsoil 75W-90 Severe Gear in my 96 crown vic.
Rear Axle:
Capacity:
-02: ~3.75 pints
03+: ~5.0 pints
Service refill capacities are determined by filling axle 1/4 inch to 9/16 inch below bottom of filler hole. Vehicle must be level with ground.
75w140 is spec'ed for the rear axle bearing TSB kit, and factory fill for Limo and now Police applications. Most use 75w140 when changing the differential fluid
80w90 was factory fill for most years
Traction-lok axles also require 4oz of Motorcraft XL-3 friction modifier
I plan on putting Amsoil 75W-90 Severe Gear in my 96 crown vic.
I split the difference and went with 75W110.
Get a synthetic brand of your choice in a 75w-90 unless you want to loose around town MPG. Once the axle is up to temp, there is an almost undetectable increase in MPG, but around town you will thank the 75w-90. If you are towing, racing, have some monster HP, or have a strech limo, then by all means a 75w-140 may be the better choice. But for a daily driver that sees normal driving, the thinner is my choice. Also, if you think about it, why did all older 8.8" axles come with 80w-90 dino gear lube? If 140 was really needed, wouldn;t you think they would have used it years ago?
Fordiesel69, you make a lot of sense. How about the blast I make to Texas twice a year in the 110 degree summers at 75 mph, any advantage to the 75W-140 then? Just me, the wife, and ALL of HER luggage.
Put an finned aluminum diff cover on if you're worried about heat.
Amsoil Severe Gear is a stout oil.
Amsoil Severe Gear is a stout oil.
Originally Posted By: Johnny
How about the blast I make to Texas twice a year in the 110 degree summers at 75 mph, any advantage to the 75W-140 then? Just me, the wife, and ALL of HER luggage.
I wouldn't think it will make a difference to be honest. Middle East versions of these cars come with 80W-90 from the factory. So I reckon it must be good enough. Unless, of course, it's a form of cost cutting, which Ford is notorious for.
How about the blast I make to Texas twice a year in the 110 degree summers at 75 mph, any advantage to the 75W-140 then? Just me, the wife, and ALL of HER luggage.
I wouldn't think it will make a difference to be honest. Middle East versions of these cars come with 80W-90 from the factory. So I reckon it must be good enough. Unless, of course, it's a form of cost cutting, which Ford is notorious for.
Originally Posted By: Johnny
Fordiesel69, you make a lot of sense. How about the blast I make to Texas twice a year in the 110 degree summers at 75 mph, any advantage to the 75W-140 then? Just me, the wife, and ALL of HER luggage.
I think your driving sounds like mine. 3-4 guys on a 600+ mile trip every other month going 70-75 in my old unmarked police cruiser. Axle temp is ok to hold hand on the cover after the trip but my ambient is 70-85 dgrees and I have more rear weight. I have severe temps where I live, so seeing 7-45 degrees F is common in the winter. I was shocked to remove the axle cover, and have the 75w-140 stay in a jel form when it was 12 degrees outside. Although the mobil 1 75w-90 did not flow like a summer day, it still did flow out decent when I remove the cover. Even if the 90 cut a few k miles off my total axle life, I think it is a good trade off with the upward trend of gas prices. Every little mod you make equals 0.3 MPG and will add up after you do a bunch of little things. I can say when I bought my car 21MPG was all I could get. Now with a total synthetic driveline and a few extra PSI in tires I can make 23MPG without even trying. I had a peak of 24.86 MPG once which is nearly unheard of with a steep 3.55 ratio limited slip axle.
Fordiesel69, you make a lot of sense. How about the blast I make to Texas twice a year in the 110 degree summers at 75 mph, any advantage to the 75W-140 then? Just me, the wife, and ALL of HER luggage.
I think your driving sounds like mine. 3-4 guys on a 600+ mile trip every other month going 70-75 in my old unmarked police cruiser. Axle temp is ok to hold hand on the cover after the trip but my ambient is 70-85 dgrees and I have more rear weight. I have severe temps where I live, so seeing 7-45 degrees F is common in the winter. I was shocked to remove the axle cover, and have the 75w-140 stay in a jel form when it was 12 degrees outside. Although the mobil 1 75w-90 did not flow like a summer day, it still did flow out decent when I remove the cover. Even if the 90 cut a few k miles off my total axle life, I think it is a good trade off with the upward trend of gas prices. Every little mod you make equals 0.3 MPG and will add up after you do a bunch of little things. I can say when I bought my car 21MPG was all I could get. Now with a total synthetic driveline and a few extra PSI in tires I can make 23MPG without even trying. I had a peak of 24.86 MPG once which is nearly unheard of with a steep 3.55 ratio limited slip axle.
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