getblown5.9

i have the nv5600 at 68,000 miles with fast coolers and its been shifting hard/rough, so last night i drained the fluid (an ugly brown looking color, not sure if it was stock or not)

anyway it took 5.5 quarts of the royal purple synchromax, it really was purple

my first impressions are WOW, it shifts with half the effort, and does NO grinding at all, took alot of the "notchyness" out of the shifts. last night it was 35* but i ran it hard for 34 miles and could not get the tranny temp up to 100* on my gauge...its about useless as it never gets warm

just a review from me, i tried it, and i love it

PsRumors

Nice to know. I need to do a service to mine and have been trying to decide which fluid to use.

Do you think the coolers are even necessary?

getblown5.9

only if you tow heavy id say...since i run empty i dont need them but i wont take them off because of the time, the mess, and there is no need to.

Dusty Ratcliff

How hot did it run before?? I just had to put a mainshaft in my NV4500 & put Lucas 75/90 trans/diff lube back in mine, am afraid it might be a little thick, but that was my only option at that very moment, had to have the truck back, haven't noticed any stiffness since the weather has cooled down though, have run it going on 3 weeks now w/no noticable problems, and shifts are smooth as silk, might look into the royal purple lube in the next couple of weeks though. Dusty

getblown5.9

with what it had before it would run 100-125* unloaded at highway speeds, and with a load or the small trailer i pulled i got it up to almost 150* nothing severe