05 Ford Explorer gear oil question

Messages
472
Location
IL
The EX calls for 75-140 in the rear, with 4oz of friction modifier. The rear diff on this truck is known to have a harmonic whine under load. I did a gear oil change with Supertech 75-140 and Motorcraft's friction modifier. Noise was still present. I guess im out of luck getting that thing to quiet down. However, the front calls for 80-90, which I changed out with Supertech 75-90. After about 2 months or so, I am now getting noise from the front end under load, only at certain speeds. This I am assuming is due to the way Ford's advancetrac operates, causing the front diff to operate only during certain times. Is this correct?? Also, would it be an option to go thicker in the front, say to 75-140 to attempt to quiet it down, or would there be adverse effects due to using a thicker gear oil??
 
Messages
4,912
Location
Lakeville, MN
My 2004 F150 has had a whine in the rear differential for a while now. Due to service on a rear axle bearing, the gear oil was changed and I used the Supertech 75-140 due to bad prep on my part meaning Wal-mart was the only place open at that hour... The whine is louder and more annoying on the Supertech than it was on the previous Valvoline 75-140. Just another data point to consider.
 
Messages
1,848
Location
FEMA Region 4
I would use a better gear oil (like Royal Purple or Amsoil Severe Gear), stick with the recommended weights and see what happens. You might be very surprised at the outcome. Dollar for dollar, pound for pound these are (arguably) the best two gear oils on the market right now. smile
 
Last edited:
Messages
24,710
Location
Dallas,Tx USA
Swing by a Ford dealership and get some Motorcraft 75W140 and a bottle of the friction modifier (for the rear diff) and some Motorcraft 80W90 for the front. Can't go wrong with OEM.
 
Messages
1,848
Location
FEMA Region 4
Originally Posted By: aquariuscsm
Swing by a Ford dealership and get some Motorcraft 75W140 and a bottle of the friction modifier (for the rear diff) and some Motorcraft 80W90 for the front. Can't go wrong with OEM.
Though I think RP and Amsoil are light years ahead of any OEM, Motorcraft is still leaps and bounds better than Supertech. You really can't go wrong either way! Buy once, cry once! thumbsup
 

lugNutz

Thread starter
Messages
472
Location
IL
Originally Posted By: aquariuscsm
Swing by a Ford dealership and get some Motorcraft 75W140 and a bottle of the friction modifier (for the rear diff) and some Motorcraft 80W90 for the front. Can't go wrong with OEM.
I would typically agree regarding OEM, but I have read around the internet and it seems as though paying the higher dollar amount for the Motorcraft fluid, doesn't make sense. From what I have read, this is a problem that isn't "solved" by the brand of fluid, but some fluids supress the noise better than others -- Motorcraft not being one of them from what i've read... unfortunately.
Originally Posted By: jk_636
I would use a better gear oil (like Royal Purple or Amsoil Severe Gear), stick with the recommended weights and see what happens. You might be very surprised at the outcome. Dollar for dollar, pound for pound these are (arguably) the best two gear oils on the market right now. smile
I originally put in RP 75-140 in the rear and didn't add FM as RP stated that it already contained it. The noise was just as apparent as it is now with the Supertech fill. I've heard mention of the Amsoil severe gear a few times, but I have yet to try it. Hoping others with this same Ford rear-end issue have tried it and can chime in.
 
Messages
2,053
Location
Detroit, MI
What kind of noise are you hearing from the front? Are you sure that is actually coming for pm the differential? These trucks are great for wheel bearings going bad all of the time. The Awd transfer cases are horrible also. I had have several of these rebuilt on customers vehicles. Just curious if it is actually a problem with your differential or fluid and not something else?
 
I swore my 04 had gear issues too after reading all the symptoms on line. When I finally took it to a shop a year later 3 of 4 wheel bearings were toast and the rear end was perfect. The IRS bearings sound just like bad gears when they go out.
 
Messages
1,848
Location
FEMA Region 4
LugNutz FWIW I always add FM whether the product says it contains it or not. In this case, too much is better than none at all. If you have tried several gear oils and the noise remains, this is starting to sound like less of a fluid problem and more of a parts issue. Sorry man...this could get expensive sick
 
Messages
15,585
Location
Santa Barbara, CA
Originally Posted By: Johnny248
What kind of noise are you hearing from the front? Are you sure that is actually coming for pm the differential? These trucks are great for wheel bearings going bad all of the time. The Awd transfer cases are horrible also. I had have several of these rebuilt on customers vehicles. Just curious if it is actually a problem with your differential or fluid and not something else?
This, check wheel bearings and transfer case. I don't think I have ever seen a front diff on one of those explorers torn apart in the 7 1/2 years I have been at the dealer. I can't count how many times we have done front hub bearings and rear wheel bearings.
 

lugNutz

Thread starter
Messages
472
Location
IL
Originally Posted By: bdcardinal
Originally Posted By: Johnny248
What kind of noise are you hearing from the front? Are you sure that is actually coming for pm the differential? These trucks are great for wheel bearings going bad all of the time. The Awd transfer cases are horrible also. I had have several of these rebuilt on customers vehicles. Just curious if it is actually a problem with your differential or fluid and not something else?
This, check wheel bearings and transfer case. I don't think I have ever seen a front diff on one of those explorers torn apart in the 7 1/2 years I have been at the dealer. I can't count how many times we have done front hub bearings and rear wheel bearings.
If it were the wheel bearings, wouldn't there be a noise at all times, not just under load? If I let off the gas and coast, the noise goes away. The noise is like a constant tone, hard to explain but similar to driving next to very noisy tires on the highway with your windows down. This is the first 4x4 i've worked on or for that matter, owned. Please correct me if I'm wrong -- I did some research and the only information that I have found is that under 40 MPH the advancetrac system is AWD. After 40 MPH its RWD until the system is reactivated by changes in traction or stability. What leads me in the direction of the differentials is, in my case I used to hear the constant hum anywhere from 20 to over 75, louder with increasing speed, but once I got above 75, it would suppress. The front just started making noise and it is only between 25-40, then it goes away. shrug
 
Messages
242
Location
twin cities mn
Originally Posted By: MNgopher
My 2004 F150 has had a whine in the rear differential for a while now. Due to service on a rear axle bearing, the gear oil was changed and I used the Supertech 75-140 due to bad prep on my part meaning Wal-mart was the only place open at that hour... The whine is louder and more annoying on the Supertech than it was on the previous Valvoline 75-140. Just another data point to consider.
Did you add Friction modifier to your 2004? There was a service bulletin on it for noise and performance. It started with the limited slip only, but later they added the open rear ends as well. My rear end gears were replaced at 31k miles under warranty. It started with a light whine, but quickly turned into a howl. When the gears were replaced they added modifier to it and the tech told me when I have the fluid changed in the future make sure it is added. They used it when they did my axle seals as well.
 
Messages
4,670
Location
Massachusetts
There is absolutely nothing wrong with Supertech gear oils. They are fine for your application. I certainly wouldn't spend $17.88 a quart on boutique gear oil for a decade old Exploder. X3 with Johnny and bdcardinal. We replace wheel bearings all the time in these. I would start there.
 
Messages
4,670
Location
Massachusetts
OK. An instance where a budget gear lube barely cut it. Batches vary, just ask Ashland and it's NOACK numbers in the NextGen line. That's why there are entities that randomly sample. I'll stick with my original statement that in this application, ST gear lubes are fine.
 
Top