Attention: TDR Forum Junkies 
NV5600 Oil Change...some interesting findings...
OK, so based on UOA, my Amsoil MTF had sheared a little bit in 10k miles of non-towing. I don't feel Amsoil MTF was the problem, I just think these trans are hard on any oil. I had also added 7 ounces of LSD additive to the Amsoil MTF about a month ago (to the oil which already had 10k on it) and saw no improvement whatsoever.
So, based on suggestions from others, I took a chance and installed 2 quarts of Redline MT-90 (the 75w90 weight trans oil) and 7 quarts of Redline MTL (the "synchromesh" type, 5w30 weight gear oil). The reasoning behind mixing the two weights was to slightly thicken the trans oil to counteract shear. And I simply chose Redline because of convenience, you could also do this with Amsoil (MTF and MTG) or RoyalPurple (Synchromax and 75w90 MaxGear) and others.
And before someone asks, I have Fast Coolers on the truck... the reason I was able to get 9 quarts of oil in the trans. With the Fast coolers, the trans holds an almost perfect 6 quarts to the "normal" fill point. I filled throught the Fast Cooler's fill port to get the additional oil into the trans. I overfilled once before and immediately notice the trans was running "warmer" than normal fill temps, although the trans acted no different, it simply ran warmer than normal. I attributed this to possibly starving something in the trans and that starved part was heating up, which was a possiblility. Then someone else made the comment that possibly the oil was acting like a heatsink... there is a part running hot at normal fill levels and the excess oil from overfilling is pulling that extra heat out of the part causing the oil to run warmer. Since there isn't much difference in the temps (about 40*F between normal and overfilled the last time I did this without FastCoolers), there's not much danger in hurting the oil itself as we are still well below the 300*F range spec'd by most oils.
I looked at levels in the trans... filling to the top of the PTO covers would almost completely submerge the bottom (counter?) shaft and would have the syncronizers partially submerged. I state this as a point of reference only. I also want to add my temperature sending unit is in the bottom section of the passenger's PTO cover, not the FastCooler's sending unit port.
To change brands of oil, I had to remove one of the FastCoolers to "swab" the bottom of the trans out... by only pulling a bottom PTO cover bolt, you are still leaving almost 0. 5 quarts laying in the bottom of the trans. Upon removing the Coolers, I found the bolts were pretty corroded and stiff... they have been installed since late October. I neversiezed the shanks of the bolts when I reinstalled them... I will do the passengerside when I change fluids again. I will recommend neversiezing the bolts when installing the Coolers new to prevent this corrosion.
I took it for a short drive last night and the shifting was slightly improved... the Amsoil was a good when new; but it had started falling off, most likely from being sheared. This AM it was around 35*F and I thought if I was to see unusually stiff shifting, this would show it. Shifting was "normal" as I would have expected... took a few blocks to really limber up, but that is the norm for this trans, really no change. On the drive to work, I should have been just slightly pulling the needle off cold (100*F)... I made it to just over 130*F in the same ride. The trans was shifting nice by the time I got into the office (I drive mostly interstate, short the first 6 and last 6 miles). No other wierdness was noted... the temps were exactly what I predicted they would be.
All in all, this is one of the nicest shifting "blends" I have ran... I figure I will run this blend during the summer and run straight MTL in the winter months (when its really cold). I will also note that the ones that recommended the "blend" also recommended using a few ounces of Ford LSD friction Modifier, but I figured I'd try straight oils first. I also plan on a UOA of this fluid "blend" to find out how it actually works in the real world. And as always, I will let everyone know if something becomes abnormal...
steved
OK, so based on UOA, my Amsoil MTF had sheared a little bit in 10k miles of non-towing. I don't feel Amsoil MTF was the problem, I just think these trans are hard on any oil. I had also added 7 ounces of LSD additive to the Amsoil MTF about a month ago (to the oil which already had 10k on it) and saw no improvement whatsoever.
So, based on suggestions from others, I took a chance and installed 2 quarts of Redline MT-90 (the 75w90 weight trans oil) and 7 quarts of Redline MTL (the "synchromesh" type, 5w30 weight gear oil). The reasoning behind mixing the two weights was to slightly thicken the trans oil to counteract shear. And I simply chose Redline because of convenience, you could also do this with Amsoil (MTF and MTG) or RoyalPurple (Synchromax and 75w90 MaxGear) and others.
And before someone asks, I have Fast Coolers on the truck... the reason I was able to get 9 quarts of oil in the trans. With the Fast coolers, the trans holds an almost perfect 6 quarts to the "normal" fill point. I filled throught the Fast Cooler's fill port to get the additional oil into the trans. I overfilled once before and immediately notice the trans was running "warmer" than normal fill temps, although the trans acted no different, it simply ran warmer than normal. I attributed this to possibly starving something in the trans and that starved part was heating up, which was a possiblility. Then someone else made the comment that possibly the oil was acting like a heatsink... there is a part running hot at normal fill levels and the excess oil from overfilling is pulling that extra heat out of the part causing the oil to run warmer. Since there isn't much difference in the temps (about 40*F between normal and overfilled the last time I did this without FastCoolers), there's not much danger in hurting the oil itself as we are still well below the 300*F range spec'd by most oils.
I looked at levels in the trans... filling to the top of the PTO covers would almost completely submerge the bottom (counter?) shaft and would have the syncronizers partially submerged. I state this as a point of reference only. I also want to add my temperature sending unit is in the bottom section of the passenger's PTO cover, not the FastCooler's sending unit port.
To change brands of oil, I had to remove one of the FastCoolers to "swab" the bottom of the trans out... by only pulling a bottom PTO cover bolt, you are still leaving almost 0. 5 quarts laying in the bottom of the trans. Upon removing the Coolers, I found the bolts were pretty corroded and stiff... they have been installed since late October. I neversiezed the shanks of the bolts when I reinstalled them... I will do the passengerside when I change fluids again. I will recommend neversiezing the bolts when installing the Coolers new to prevent this corrosion.
I took it for a short drive last night and the shifting was slightly improved... the Amsoil was a good when new; but it had started falling off, most likely from being sheared. This AM it was around 35*F and I thought if I was to see unusually stiff shifting, this would show it. Shifting was "normal" as I would have expected... took a few blocks to really limber up, but that is the norm for this trans, really no change. On the drive to work, I should have been just slightly pulling the needle off cold (100*F)... I made it to just over 130*F in the same ride. The trans was shifting nice by the time I got into the office (I drive mostly interstate, short the first 6 and last 6 miles). No other wierdness was noted... the temps were exactly what I predicted they would be.
All in all, this is one of the nicest shifting "blends" I have ran... I figure I will run this blend during the summer and run straight MTL in the winter months (when its really cold). I will also note that the ones that recommended the "blend" also recommended using a few ounces of Ford LSD friction Modifier, but I figured I'd try straight oils first. I also plan on a UOA of this fluid "blend" to find out how it actually works in the real world. And as always, I will let everyone know if something becomes abnormal...
steved
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