Question about Valvoline 75-140

[Twisted1]

I am going to be servicing my Ford 8.8 soon, and wanted to know if I need to add Motorcraft Friction Modifier in with the Valvoline 75-140? I’ve read mixed things from adding it in with Valvoline will ruin the clutches and also the opposite that you indeed need to add it. I know that Valvoline contains friction modifier already. Just looking for the right answer.

Big thanks in advance.

 

[Timmastertech]

We always add the XL3 to the gear lube whether using Valvoline or Mobil 1 or Motorcraft gear oil

 

[BlueOvalFitter]

Yes, add it.
When I had L/S differentials I would add the FM and go find an open parking lot. I would do a few figure 8's to mix the fluid/oil and FM.
Something I learned from my dad.

 

[ka9mnx]

Why don't you ask Valvoline? I had the same question about SuperTech so I emailed Warren Distribution and they promptly replied with the answer I was looking for. The only other I know for sure is Mobil1 after they came out with the "LS" on their label.

 

[Twisted1]

Why don't you ask Valvoline? I had the same question about SuperTech so I emailed Warren Distribution and they promptly replied with the answer I was looking for. The only other I know for sure is Mobil1 after they came out with the "LS" on their label.

Didn’t think of that. I’ll give them a call tomorrow.

 

[BlueOvalFitter]

Why don't you ask Valvoline? I had the same question about SuperTech so I emailed Warren Distribution and they promptly replied with the answer I was looking for. The only other I know for sure is Mobil1 after they came out with the "LS" on their label.

I had used Royal Purple gear oil in my 77 Z/28's L/S differential, ONCE, without adding a FM. It chattered like 2 ladies cacklin like old hens! I added the FM, and she was as quiet as a church mouse.
Oh, and BTW, the RP gear oil stated on the bottle. NO NEED TO ADD FRICTION MODIFIER, or something similar to that.

 

[CharlesInCharge]

Ford is confusing with the need for this extra dose of friction modifier that I've never understood, nor is it always clear.

I've been told that if unsure then to add it since it won't harm anything, but I'm NOT SURE if that information is accurate. So I'm a bit paralyzed in doing some gearbox drain and fills myself...

 

[oldhp]

I've used Valvoline 75W90 / 75W140 in many posi style clutch pack rear ends. Never added FM or needed it. No chirping clutch disc's ever. Too much FM clutch packs won't hold when needed. I was always told (and did) sneak up on the FM, start with none, add if needed, only 2oz at a time. I only use Redline gear oil now and have never added FM to any of my posi rear ends, all have been quiet.

 

[The Critic]

Valvoline 75W140 already contains the modifier, but the percentage is unknown. Too much modifier will cause performance issues and accelerate oxidation of the gear oil. So fill the differential with the fluid only, then see if there is chatter. Most likely, you will end up adding 1/2 of the usual amount of modifier.

 

[ka9mnx]

I had used Royal Purple gear oil in my 77 Z/28's L/S differential, ONCE, without adding a FM. It chattered like 2 ladies cacklin like old hens! I added the FM, and she was as quiet as a church mouse.
Oh, and BTW, the RP gear oil stated on the bottle. NO NEED TO ADD FRICTION MODIFIER, or something similar to that.

Crazy right? I used the M1 LS and SuperTech straight out of the bottle with no problems in my F150 (limited slip in fromt and rear).

 

[The Critic]

Crazy right? I used the M1 LS and SuperTech straight out of the bottle with no problems in my F150 (limited slip in fromt and rear).

It all depends on the FM treat rate. Not all brands use the same amount and every OEM differs in their recommendation. So for some brands it will be adequate, but for others, nope.