What rear diff fluid do i need to use door code is 42 please help!!!!!!

[dinks07]

doing rear diff what fluid do i need to use door code is 42

 

[LONO100]

i have axle 42. this is an open diff with 4.10 gearing. i just changed my diff fluid. ford says to use 75W140. other memebers ive talked to who live in desert climates say they use 85W140 fluid. id go synthetic since you dont change the diff fluid very often. what makes you want to change your diff fluid now?

 

[dinks07]

I am just changing it due to age I just bought it and it has 106,000 miles on it and has never been done jsut want to get some fresh fluid in there. I thought i read it was
80w90.

 

[ncranchero]

Current Ford recommendation is:

Lubricants and Sealants
SAE 80W-90 Premium Rear Axle Lubricant
XY-80W90-QL (conventional axles) WSP-M2C197-A

SAE 75W-140 Synthetic Performance Rear Axle Lubricant F1TZ-19580-B ( Traction-Lok® axles) WSL-M2C192-A
&
Additive Friction Modifier
C8AZ-19B546-A EST-M2C118-A

 

[LONO100]

hey ranchero, having just installed the lockers, the gear oil i used (valvoline full synthetic 75w140) says on the label that the limited slip additive is not needed when using this oil. i read that you have to put the additive if you run lockers but being that i used this particular oil, i didnt add any. should i, or am i good?

 

[ncranchero]

Don't think you need to since you don't have the clutch packs.

 

[dinks07]

so if i use the 75w140 synthetic it will be fine right even though I have a open diff

 

[ncranchero]

Fords specs are minimum requirements. I would think the 75W140 Synthetic would be much better.

 

[dinks07]

ok great thanks thats what i will use then just trying to make sure this thing is in great running condition

 

[Clusterpup]

hey ranchero, having just installed the lockers, the gear oil i used (valvoline full synthetic 75w140) says on the label that the limited slip additive is not needed when using this oil. i read that you have to put the additive if you run lockers but being that i used this particular oil, i didnt add any. should i, or am i good?

You don't need the additive at all, even if you use conventional oil with the locker.

 

[05Sporttrac1217]

My wifes 95' explorer makes this helicopter sound coming from what i think is the rear diff, i tried adding fluid, it help for a little but now the sound is back....Did i use the wrong weight fluid? Whats the best to use?

 

[LONO100]

cool, thanks. i read somewhere that the additive is needed when running lockers even thought there is a lack of the clutch packs which seemed a little odd to me. thanks fellas. you learn something new everyday.