Does anyone know what fluid to use!?

[CaptKirk]

Yes, I tried to search for this and I called 3 different Ford dealers and they all had a different answer. And none of them matched the Haynes manual!
O.k. So, I have 100,000 miles and want to change the front and rear differential fluids. What type do I use. Does anyone know for sure? Also, I do not believe I have the limited slip, but how do I know for sure.
Thanks for help on this!

 

[ExplorerDMB]

Pretty sure for non-LSD it's 75-90 weight

-Drew

 

[CaptKirk]

Thanks for the reply but, Haynes says 75W150 synthetic.
One dealer says 75w150 non-synthetic.
The others say something totally different.
Anybody.......

 

[chriswells78]

I was pretty sure that mine was LSD, and supposedly the LSD does not need to be changed due to synthectic fluid according to the Haynes manual and my owners manual states that it calls for synthetic.

In the little maint. schedule that came with mine, it never mentions diff fluid. However, I thought my buddy had LSD in his 02 Sport Trac, the dealer told him that he needed his diff fluids changed and wanted to charge him $45 per axel, his little book doesn't mention changing diff fluid either.

So I am a little confused on this issue myself.

 

[rizzjc]

Your LSD should have a tag on it telling you what it is, and what type of fluid to put in it. My '97 takes 75W140 SYNTHETIC ONLY, which is what it was filled with from the factory, and what I use. I've used 75W90 in the front, synthetic. I don't see any reason for any of them to REQUIRE non-synthetic.

 

[CaptKirk]

I saw the tag on mine and it had some numbers on it. Didn't say anything about what type to use. At least what I could tell.

 

[rizzjc]

Might be two tags. 'Course, if it has ever been serviced before, they may have removed the tag. What exactly are the specs on the vehicle? Given that, someone here could very easily tell you what is in it. Mine is a '97 V8 AWD with the 3.73 LSD rear, and I know it required 75W140. "course, I've had it changed at the shop several times during its lifetime, so who knows what they put in it.

 

[alexefron]

do a search and you'll find that a lot of different people recomend a lot of different things. if you do indeed have the l/s youll need a few ounces of friction modifier for it to work properly

 

[CaptKirk]

Thanks, but I tried the search and you are right. There are so many different oil weights that people use its amazing. I want to put in what Ford recommends and the dealers can't even tell me that. I will have to call a dealer and give them the Motorcraft part number from my manual and see what type it is.

 

[JDraper]

You won't go wrong if you use synthetic. Definitely need a friction modifier if its an L/S differential. I'd recommend the 75w140 too. That's what I used in my '01 diffy's and all the other X's I've worked on.

 

[celly]

I just went with Amsoil Severe Gear on both my front and rear differentials (I have 3.73 LS in the rear). Didn't bother with a friction modifier because I read in enough places that it's not needed with such a high quality oil. Went with 75/90 in the front and 75/140 in the rear (Amsoil recommendations). Probably the most expensive option out there, but I plan on keeping my Eddie for a LONG time.

 

[rizzjc]

Yes, use the same Amsoil stuff. No friction modifier needed. Whiever you use, read the label. It will tell you if you need a friction modifier or not. And from everything I've read, it's just to make you feel happy not hearing the "clatter", so if it doesn't "clatter" then you don't need it. If it does, then you add a bottle in (it's like 4-6 ounces).

 

[BrianV]

Yes, use the same Amsoil stuff. No friction modifier needed. Whiever you use, read the label. It will tell you if you need a friction modifier or not. And from everything I've read, it's just to make you feel happy not hearing the "clatter", so if it doesn't "clatter" then you don't need it. If it does, then you add a bottle in (it's like 4-6 ounces).

Glad I found this thread since I have 3.73 w/ LS and I plan on draining and filling this weekend. I'll probably just use a synthetic like Amsoil or RP. Looks like 75/140 is the right weight for me. How many quarts do I need to buy for the job?

Thanks

 

[badgett]

It's 5.8 pints. However many quarts that is

 

[BrianV]

It's 5.8 pints. However many quarts that is

Well 2 pints = 1 quart so still less than 3 quarts.

 

[alexefron]

just short of 3

 

[eaglescout711]

Yes, I tried to search for this and I called 3 different Ford dealers and they all had a different answer. And none of them matched the Haynes manual!
O.k. So, I have 100,000 miles and want to change the front and rear differential fluids. What type do I use. Does anyone know for sure? Also, I do not believe I have the limited slip, but how do I know for sure.
Thanks for help on this!

I had the same problem. Which fluid? Which type of diff do I have. Manual listed info on both types of axles but did not tell me how to identify which type was on my X. Called my Ford dealer and the parts manager was very helpful. Gave him my VIN but he was still unsure because of the build date. But I took a picture of the diff ID tag with my phone.

He told me to look on the bottom row of numbers. The first numbers listed are the final drive gear ratio; my tag had 3 73 88 0C07. He said there would be a "L" stamped in the space between the 3 and 7 if the diff was L/S. So no "L" means I have a standard axle. Hope this helps another DIY'er

 

[SoNic67]

The tag should say what fluid it takes. I took a pic of my rusted read diff (AWD) right now and it is clear: