Changing fluids, couple questions?

Sycostang67

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Sep 27, 2019
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Kuna, ID
My car recently passed 100k and I'm about to go change all the fluids. I've been looking into using the Redline 75-140 in my diff and it says you likely wont need to add the LSD friction modifier. Has anyone used this stuff that can attest to this? The friction modifier is only a few dollars more so it's no big deal but would rather not spend the money if I don't have to. I'll also be changing the transmission fluid as well, Mercon V synthetic ATF is what seems to be correct for a 5 speed manual?

What are you guys doing for coolant? I assume I still have the OEM ford gold, should I put that back in or flush it all out and go with something else?
 
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7991LXnSHO

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As for the coolant, I’d recommend flushing it all out and using what Ford specifies. If the green or universal Prestone was all it took to prevent corrosion, they would have gone with the cheaper stuff.

Now as far as the differential, clutch chatter stinks as bad as slipping clutches. It should not hurt to add it anyway.
 

Sycostang67

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Sep 27, 2019
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Kuna, ID
Ok, the Ford Gold equivalent is a Zerex G05, it's the same HOAT style coolant as the Gold and has ford cars from 2004-2017 listed under applications. I'll grab the bottle of friction modifier as well, I guess too much would be better than not enough.
 
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David Young

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As for the coolant, I’d recommend flushing it all out and using what Ford specifies. If the green or universal Prestone was all it took to prevent corrosion, they would have gone with the cheaper stuff.

Now as far as the differential, clutch chatter stinks as bad as slipping clutches. It should not hurt to add it anyway.


I had my local Ford dealer change my gears to 3.73 a few years ago in my 2011 v6. Same rear end as used in the GT, 8.8. They told me it would be good to change the fluid after 500 miles. After 500 miles I did my first burnout at my house on my way to buy new fluid and a 4 oz bottle of friction modifier from my Ford dealer. It did a one wheel peel :(. I talked to the guy who did my gears, I told him both rear wheels don't work. He told me he put in two 4 oz bottles of friction modifier to help the gears break in and said when I change the fluid and put just one 4 oz bottle of friction modifier everything will be back to normal. I told him OK. I went home and changed the rear gear lube but only used 3 oz of the 4 oz bottle of friction modifier. I figured I could add the other oz if I heard clutch chatter. I didn't hear anything and that was several years ago. I now have both rear tires pulling :)

Too much friction modifier is a bad thing :(. So be careful with it..................
 
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Sycostang67

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Sep 27, 2019
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Kuna, ID
Got it all done, ended up going with Royal purple max gear 75w-140 for the diff and there Max ATF for the transmission. It's supposed to be a replacement for Mercon, also put Zerex G05 in the cooling system. The transmission feels a little smoother now which is nice. I was gonna try the Redline in my diff but the weight I needed was the only one I couldn't readily get through my work, would of had to submit a special request.