NV4500 Oil Fill

[Mario]

I had been reading in various forums of guys recommending to fill this transmission with 5 quarts.  After I overhauled it that is what I did, and I was happy with it.  The other day I took it on the interstate for the 1st time, and the outside temperature was in the 90s.  I had been driving in the 80 mph range.  Shortly after being on the interstate, I started noticing a fluid around the shift tower.  I still have to work out my transfer case shift linkage, so I didn't have the shift boot on the transmission.  Needless to say it was the transmission oil spewing out of the shifter.  I routed the vent tube up into the engine compartment with about 3' of 3/8" tube.  I don't know if that made a difference or not.  In the future, I would add 4.5 quarts, and see how it does at high speed.  I do believe in overfilling within reason because replacing drivetrain components and lost drive time sucks.  I just thought I'd share so that people doing searches in the future will be able to make a better decision.

[bake74]

     The NV 4500 is suppose to take 1 gallon (4 qts) of oil.  If you put 5 in, you are causing a build up of pressure that could damage your seals and gaskets.
     Foaming can be caused from too little or too much oil in the case.  In basic terms it is allowing air to mix with the oil because the level in not correct and ends up pushing oil out.  A lot of times this is mistaken for a leak, when in reality the level is not right.