Rear Differental Fluid Spec - 2024 Expedition Timberline

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Jozef Zoldos

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Hello All

Looking for the correct answer. I have a 2024 Expy Timberline with 30,000 miles. Looking to do fluid change on front and rear differentals and transfer case. The specific question that I have is about the rear differental which is an eLSD in my trim.

I purchased 75W85 gear lube for the rear differental. I am getting conflicting information on the internet about whether or not I need to add 4 oz of friction modifier. Gemini AI says that I do not need to add friction modifier because it is a "Control Trac eLSD that utilized an electro-hydraulic pump to engage the internal clutches unlike the traditional mechanical limited-slip differentals". Gemini goes further to state that if I add a friction modifier, it could result in clutch slippage, reduced capability, and computer confusion leading to error messages. The Service Manager in my local Ford Dealership, however, told me that I need to add it.

What is the correct answer?

Thanks in advance....

Joe
 

Grrumpy

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On-line 2024 Expedition Owners Manual specifies rear with limited slip requires friction modifier....4 ounces.
Also, 75-85 gear fluid needs to be full synthetic.
 
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DieselMonk

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just what Grrumpy already said. You forgot to mention it will increase heat too without the friction modifier.
 

Grrumpy

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Also......ask yourself.....what does an AI know about vehicle maintaince ??? Does it own or drive a vehicle ????? Does it service a vehicle ????
Will it reimburse you if you follow it's advice and that advice causes damage....your rear end grenading ????:rotflmao:
 
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