ZF5 & Limited Slip Diff

[Diesel Max]

Two questions:

I have a 10.25 limited slip diff with 4:10's. If synthetic oil is used, do you still need to add the friction modifier ? Is 75W-90 the correct oil for this diff ?

I have a ZF5 trans. Is regular Mercon ATF ok for this application or should it be Synthetic Mercon ATF ??


Thanks for the input

 

[Pearl_Diesel]

For the ZF-5, Regular Mercon is what I used, without trouble, and it's what the service manual says.

 

[RLDSL]

With most syn in the rear, you don't need the additive, but if you experience chattering, then go ahead and put it in, Many syn makers have their own type of additive for posi in that case.

Regular ATF is the spec for the ZF. Running a synthetic ATF would make it behave better when cold ( easier cold shifts ). if you have a noisy box you can get a 30wt synthetic atf to put in the thing and that works great.

 

[91crew]

Where are you guys getting the 30wt synthetic atf? I cant find it anywhere.

 

[Black dawg]

I have syn75/140 in my 10.25. the differential used to work really good and now with the synthetic not so good. so Id say no additive is needed, its already slippery enough.

 

[RLDSL]

Where are you guys getting the 30wt synthetic atf? I cant find it anywhere.

I get it from Amsoil, Most of the major lubricant manufacturers make a version of it and the 50 wt synthetic atf for the heavy equipment market. the heavy wt synthetic atf is spec for the boxes in a lot of the heavy equipment out there

 

[6 Nebraska IDIs]

I'm running 20wt Synthetic Archer ATF in my ZF and it shifts pretty good considering the clutch isnt bled properly yet. It is a bit noisy though. I noticed it whines a bit in reverse.

 

[reklund]

My vote is for conventional Dex III ATF and conventional 80-90 in the diff with the friction modifier. It's what the truck was designed to run on.

Ryan