Friction Modifier FM 7099 for a differential w/ wet brakes

[Bruce F]

New member, first post.
Hope I'm in the right forum.
Or should I repost in a different?

Zoom Boom 6042 by Care lift. Basically a "Lull".
I'm doing a PM drain and refill on two differentials on a telehandler for a customer.
Also doing/did the final drives.
I was considering using a synthetic 75W-90 in the finals (because I have a few pails of it), but just bought another pail of the 80W-90.

Would the 75W-90 full synthetic have been an acceptable substitute in the finals?

Brakes have no issues, that I know of.

Owner's manual specs 80W-90 GL-5 and adding 1/2 liter of FM 7099 to each diff.

Anyone have good info what FM7099 is?
What could I use as a substitute?
Where could I buy FM 7099(F)?

Thanks for any help!
Bruce

 

[MolaKule]

A synthetic LS 75W90 GL-5 diffy lube should cover the requirements.

Apparently the addition of an FM is to reduce chatter in the differentials, but I would first add the LS 75W90 GL-5 diffy lube and operate it to determine if any chatter is present.

If any chatter is heard or felt, then an additive such as these,

https://www.oreillyauto.com/shop/b/...e/gear-oil---additives/additives/b0c9733f752d

would be needed.

 

[Bruce F]

A synthetic LS 75W90 GL-5 diffy lube should cover the requirements.

Apparently the addition of an FM is to reduce chatter in the differentials, but I would first add the LS 75W90 GL-5 diffy lube and operate it to determine if any chatter is present.

If any chatter is heard or felt, then an additive such as these,

https://www.oreillyauto.com/shop/b/...e/gear-oil---additives/additives/b0c9733f752d

would be needed.

Thank you for the reply.

So, you're suggesting to use the full synthetic 75W-90 in the differential.


The diff appears to be an open diff. I imagine the additive is for the wet brakes.

 

[lakestone]

I would get some Valvoline Synthetic 75W-90 and call it a day. It's available everywhere.

 

[Bruce F]

@lakestone,

Thanks for the reply.

I do have full synthetic 75W-90 LS oil from a local supplier (Mobil oil product in a house brand bucket), I was just trying to get to the bottom of what is FM7099.