Transmission/rear-end Fluid Change.

Clair Smith

Active Member
Apr 4, 2012
186
13
29
Norfolk Va
I just passed 1000 miles on my GT and I changed the fluid in the transmission and the rear-end to Royal Purple and I have to say that the transmission is much easier to shift. I did not think that the shifting was bad before, but now...WOW. It is just smooth and glides into gear.

And the amount of metal in the rear-end was pretty amazing, glad I took the time to clean that out.

Oh, and I unplugged the skip-shift solenoid while I was down there.
 
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A number of 5.0 owners believe that the 6M transmission in these cars is a weak link. I know it's made in China, so that means it's probably junk. I hope Royal Purple improves the longevity of your trans, or Ford may try to void your warranty for not having Ford approved fluid in there. Just sayin'
 
A number of 5.0 owners believe that the 6M transmission in these cars is a weak link. I know it's made in China, so that means it's probably junk. I hope Royal Purple improves the longevity of your trans, or Ford may try to void your warranty for not having Ford approved fluid in there. Just sayin'

My transmission have been great so far, I think it helped to switch to the MGW shifter at 300 miles (which was as soon as I could) which provided smoother more precise shifts. The RP fluids meet/exceed Ford's recommended fluids, I am not worried about voiding my warranty. I will simply enjoy my smoother shifting transmission and be happy that my gears are bathed in nice clean fully synthetic oil...ahhh :)

I did add 4 oz of XL-3 even though the RP gear oil stated that it was not needed, I have read that the 8.8 has a propensity to make noise if you don't add the XL-3 even if the gear oil is made for LSDs.
 
excuse me for the noobish questions, but which RP fluid did you use? also what is XL-3? im interested in switching my fluid to royal purple tranny fluid as well. thank you!
 
excuse me for the noobish questions, but which RP fluid did you use? also what is XL-3? im interested in switching my fluid to royal purple tranny fluid as well. thank you!
I used this for the transmission: http://www.americanmuscle.com/royal-purple-synchromax-manual-transmission-fluid.html,
this for the rear-end: http://www.americanmuscle.com/royalpurple-maxgear-75w140-gearoil.html

Ordered them from American Muscle, because I could not find them locally and AM had good prices. They have great shipping by the way, got my order out to me in two days :)

XL-3 is a friction modifier for the LSD in the rear-end. Ford recommends that you put 4 oz in the rear-end with a fluid change. I bought mine from the local Ford dealership. This is what it looks like: http://www.frsport.com/Ford-Motorcraft-XL3-LSD-Friction-Modifier-Gear-Oil-Additive_p_2288.html


Happy Fourth :)