I'm getting ready to change my IRS diff cover with the new Ford racing one, I just purchased the 75W140 royal purple gear oil with friction modifier, Does Anybody know how many courts the IRS needs And do I need to add additional friction modifier?
Upgrading to ford racing irs diff cover
- Thread starter 04cobra7788
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The friction modifier question depends on what kind of differential you will be running.
When filling with the FRPP cover, just continue to fill until it starts to come out of the fill hole. The capacity should be similar to stock.
Best of luck with it! It's a nice upgrade.
When filling with the FRPP cover, just continue to fill until it starts to come out of the fill hole. The capacity should be similar to stock.
Best of luck with it! It's a nice upgrade.
OK thanks I will be running the stock differential I'm just upgrading the dif cover so is the additional friction modifier needed?
Royal Purple claims no extra is needed because it comes with it. I like the FRPP cover I have been running it for years.
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Yes a friction modifier is needed. Nowadays it seems like all major brands already have it mixed into the fluid so you don’t have to add it separate. Just make sure the gear oil you use has it in already and you’re ready to go. And as mentioned already, once it comes out of the fill hole you’re done and it’s full. It’s something like 2 quarts if I remember when I did mine.
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It won't hurt to put more friction modifier in even if they claim to have it added. According to Ford manual fill is 1.23-1.37 L [2.6-2.9 pints] not including the friction modifier [4 oz]. The manual also says to fill until 0.25" below the fill plug.
Okay thanks
Buddy of mine that owns a transmission shop told me he does a 4oz. bottle of friction modifier for each quart of fluid he puts in. Doesnt care if it claims to have it or not. Better safe than sorry.
Good time to replace the diff clutches while the pumpkin is out if its higher miles. Never gonna be easier and its a stupid simple job.
Anyway, 2 quarts of fluid plus a bottle of friction modifier. Lube locker gasket instead of RTV. Also a real good time to replace the rubber in the rear mount/front mounts if they aren't also done already.
Anyway, 2 quarts of fluid plus a bottle of friction modifier. Lube locker gasket instead of RTV. Also a real good time to replace the rubber in the rear mount/front mounts if they aren't also done already.
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