Posi Fluid

[PaulZ]

Last time I changed the rear fluid Naps said the fluid they gave me was fine for the limited slip. Now I remember there is a special additive Ford sells. What does it do? 99 Ranger.

 

[alwaysFlOoReD]

I believe it allows the clutchs to slip. If not added then when turning corners you will get weird sounds as the clutches grab and let loose continuously.

 

[SenorNoob]

^ He's right.

From what I've heard most synthetics either have it included (cause it doesn't really matter in an open diff) or a slippery enough on there own to not need it. Verify with whatever brand you used..

 

[PaulZ]

Thanks guys. I’ll never find the Napa receipt but sure he said I didn’t need it. Think I’ll get some anyway. Ford parts counter?

 

[SenorNoob]

Should be available from your regular parts store.

https://www.oreillyauto.com/detail/c/motorcraft/motorcraft-friction-modifier/mot0/xl3?srsltid=AU7gw4UBRv3dmCpq1qYn1wwumJfeMJZnmkA-LxuQ1J9sTOvX04nfCGSZ

 

[PaulZ]

Called them. They dont have the Motorcraft bottle but they do sell a friction modifier. Hmm, right nearby…

 

[19Walt93]

I use the Ford Performance friction modifier because it's the old formula and works better than the new environmentally friendlier stuff.
By the way, your rear end is a Traction Lok. A posi was the weak kneed GM that kept breaking until the high performance guys swapped in a Ford rear end. You wouldn't call your truck a Tacoma, would you?