Hi all. My truck has about 153K miles, and I have no idea what the service history is, so I thought it would be a good idea to replace some fluids (transmission, transfer case, rear/front diff.) After saving up some cash, I ordered all Royal Purple oil (Max ATF, Synchromax, 75-90, and 75-140.) I have an Amazon Prime membership, so I ordered all the oil online and scored free shipping, but the cost still pushed into the $200+ range.

I plan to do a fluid exchange by pumping fluid out through the transmission cooler. Is there anything special I should know about this? The transmission fluid came as a bundle pack... I will only have 12 quarts, so there will be some old fluid left behind. Any issues there?

Also, I have the 3.55 LSD rear. I don't have any Motorcraft friction modifier, so do you guys think I'll have any chattering issues? Just to make sure, I'll do some donuts and powerslides in the rain and report back.

The oil should be here Wednesday, and I'll get started on it Sunday... probably.

 

Go to the dealer and buy a bottle of Ford modifier. It's not that expensive. I'd also have more than 12 quarts of ATF available, just go to the parts store and pick up some more. You should be able to return what you don't open.

The transfer case does NOT take Synchromax, it takes ATF.

 

I got the Synchromax and skipped the friction modifier based on this FAQ...
It's also a bit of a drive to the nearest Ford dealer, but I'll get some if the life of my diff depends on it.

http://royalpurple.com/faqs-transmission.html

Should I bump the tranny fluid up to... 15 quarts?

 

The Royal Purple 75-140 going in the rear diff does not require the modifier like other diff oils. It already has a modifier in it or at least the RP 75-140 I last purchased did. I haven't had any chatter or drone out of mine after about 3K miles since I change it.

 

I would still use ATF in the transfer case, regardless of what RP says. Go ahead and pass on the modifier for now - but if it starts chattering, go get some and add it.

 

Thanks for the info guys.

I'll keep the thread updated pics and stuff when I get started.

 

I have a good friend that is a tech he tells me not to change trans fluids, He tells me just to add to them, The manager at a dealership told my dad the same thing his truck has about 180,000 not to change it. there is something about the oil and material from the clutch.

 

I may be wrong here, please correct me if I am, but I think they are referring to a flush rather than a change. It's my understanding that's it's best just to change the fluid at any mileage, but avoid an actual flushing with the machines.

 

Royal Purple is pure junk, run something worthwhile

 

Really, what is worthwhile then? And why do you say royal purple is junk?

 

hmmm, lets start with the False Advertising charges they got hammered with...

 

I can't comment on Royal Purple, but I have heard nothing but praise about Amsoil products, That is what I run in the Engine ,Trans, Transfer case, ect. I cannot run it in the rear end because of the Tru-Trac unit I have installed. I know it's a lot of $$ for fluids, but I have had good luck with it.

 

you are correct sorry i must have miss understood

 

I've heard this myth as well. I'm fairly certain it's due to shops using crappy flushing machines which dislodge deposits in the transmission without filtering them out. The deposits get everywhere clogging valves, causing slippage, heat buildup, and eventual transmission failure... I'm no expert tho.

Have you had any issues with using RP? I was just wondering. I chose RP because I had used it before in the diff and transfercase of a Chevy Trailblazer I had, and noticed small MPG gains, and the car felt "smoother." It's also cheaper than Amsoil. But then again... I guess anything would be an improvement over fluid with 60,000 miles on it.

 

A "flushing machine" should only be used in the vehicle-powered exchange mode - where it's simply reservoirs for the new and old fluid. The exchange is done with the engine running, letting the tranny pump do the work.