Differential Fluid Change

[dranger21]

My 99 has about 100,000 miles on it now so i guess its time i change the differential fluid. The truck has the off road package and i know that a limited slip diff was an option but i dont think mine has it im just not 100% sure so how can i tell. I just need to know if i need to add the friction modifier to it. Also does it really matter much whether it is 80W or 90W? Any help would be appreciated.

 

[MountainMike]

I have a 98 with the offroad package. Check you axle tag (little metal plate attached to a bolt on the diff cover). if it says 3L73, it is 3.73 gears with a limited slip. No L means open-diff. As for the weight go with what Ford wants, you can pick it up in quarts containers at your nearest dealership (for the Ford OEM motorcraft stuff).

 

[Fx4wannabe01]

Well.....when you take the cover off, inthecarrier you'll see an S-shaped clip in the middle of the spider gears and side gears. If you see that S-shaped slip, you've got the Trac-Lok limited slip.

OR...when you have the rear off the ground....spin a tire forward. If the othersides tire also goes the same way(forward), you have an LS. If it goes opposite(backward), you are open.



Ford calls for a multi-weight oil. 75W90, 80W90. If LS, don't forget your additive.

 

[dranger21]

thanks for the help. i have another quick question tho. I went to advanced auto today to get the gear oil and the guy there told me i would need 5 quarts for the rear diff. To me that sounds like a lot but i could be wrong. I just dont feel like buying that much if i dont need it. Anything decent is at least $7 a quart. Coastal brand is $13 a gallon but im not putting that stuff in.

 

[strvger]

wow, i don't remember putting that much in our 2.5t axles when i was in the army!! i'm betting he meant PINTS. just double check with them.

 

[daniel3507]

he meant pints and it does take 5 of them. i think that equals out to 2 1/2 quarts.

 

[85_Ranger4x4]

OR...when you have the rear off the ground....spin a tire forward. If the othersides tire also goes the same way(forward), you have an LS. If it goes opposite(backward), you are open.

Once you break the clutches loose in the limited slip the tires should turn in opposite directions unless the transmission is in neutral or the driveshaft is unhooked... and a open differential could do the same.

They are both set up under the same theory, but the L/S has clutches to try to keep both tires spinning at the same speed.

 

[dranger21]

he meant pints and it does take 5 of them. i think that equals out to 2 1/2 quarts.

again...this is why i usually double check what the guys behind the counter there tell me

 

[Fx4wannabe01]

My 31spline Ranger axle was completely empty(tubes and all), and it took damn near 5qts to fill the bastard up. Took the whole 1gal jug and then some.

 

[dranger21]

heres a picture of my diff. This is an open diff correct? http://i658.photobucket.com/albums/uu304/huntnfish2010/101_0284.jpg
and this is the tag on the axle. I had always thought i had 3.73 gears but aparently not. Can anyone tell me what the top line means http://i658.photobucket.com/albums/uu304/huntnfish2010/101_0283.jpg

 

[4x4junkie]

4.10 ratio 7.5" open diff built June 19 1999.

The top line I think is just the plant code #, the bottom like has the relevant info most people would need (ratio, axle size, date code)

http://www.therangerstation.com/tech_library/Axles.html

 

[Sasquatch_Ryda]

My 31spline Ranger axle was completely empty(tubes and all), and it took damn near 5qts to fill the bastard up. Took the whole 1gal jug and then some.

Aftermarket cover or something on it?

Should take just shy of 3 litres.