I know that a common shifting problem with the NV is due to overfilling. Keeping the fluid clean and cool would be the best bet. To ensure proper lubrication, that is where the viscosity is the key and just shoving in 80-90 gear oil will end the life of the NV shortly. I know on my 93 Getrag, the previous owner had 80-90 in there, I could smell it. I quickly put the recommended 5W30 grade oil in there as it should have been. 80-90 oil in our climate is near grease state most of the time..LOL..

 

thanks for clearing up my tranny panic. seems like the simple stuff is really important sometimes. i drained out the excess and it was only about half a pint. metallic grey color and not burnt smelling. if it has this metallic color -like a metallic paint job, is it time for a change? its only been 4 months or maybe 2000 miles but maybe 3000.

 

Remember there is only one oil recommended for this tranny, Castrol SyntorqLT 75w85w.
Not be confused with Syntech, it doesn't work.
Many lube manufacturers will tell you their product is compatible but to tell you the truth I personally don't believe them.
Apparently Amsoil MTG works also.
Syntorq is pricey from the dealer, a little cheaper from the GM dealer, or you can buy it in larger than qt quantities from these guys--
http://www.standardtransmission.com/dodge.html

http://www.quad4x4.com/NV4500%20Parts.htm

Could be the wrong oil is what's causing your metallic looking lube.
Apparently lubes other than Syntorque will eat the syncros like acid.

 

Bill, Standard Transmission changed to Amsoil quite awhile ago. The last time I was there they had no plans to go back to Syntorq. Apparantly their Syntorq suppler was a jerk and Charlie got tired of dealing with him. If we always went by manufacturers specs there wouldn't be anyone adding an extra qt to their Getrags, no KDP, no holes drilled in the vent under the headlight switch and many other fixes for weak designs.

Busboy, As far as overfilling slightly causing overheating. Nope. I have a temp gauge for my trans. It runs as cool, if not cooler, than it did before I started adding a little extra oil. I used to see temps up to 210. This last summer I never exceeded 190.

 

Wow, good info there. I know there were a couple other oils that were compatible with the tranny syncros, can't remember them though..

The tranny temp is a good piece of data, hard to dispute that. But, high levels can cause more hydraulic pressure on the smaller components at road speed which may or may not wear them prematurely, that being the syncros.

 

I watched a good video of how a bearing in an overfilled tranny behaved compared to one filled to the correct level, wish I could find it.
What happens though is the way most gear boxes or differentials are designed the lube is supposed to only come half way up the lowest single ball or roller bearing in the race when the gears are spinning and lowering the oil level.
If the lowest single bearing is submerged up to the bottom of the shaft that goes though it it causes the lube to pull up and around the entire bearing causing drag.
They even had a name for this phenomena but heck if I can remember it.

 

If I have to overpower a little bit of drag to get more lube to the vitals of the tranny, I'm more than willing to pay the freight.

 

i over filled my 4500 by a little and its stiff shifting and 3 gear kinda grinds if you shift to fast. should i maybe try draining a bit out? i did not drive the truck before i worked on it since it was my friends, only has 200 000km

 

Having the oil level at the manufacturer's suggested level is totally adequate to lube all the vitals.
Adding more is just asking for trouble.

 

I'll find out in a couple of days. Just took the trans in for insp and repair. The last time I had this many miles on one it was making a lot of noise. Now just getting a hint of noise when the temp gets to 160. No shifting problems or other issues. If it takes fewer parts this time, the extra oil was a plus.

 

After working with synthetic oil and gearboxes of one kind or another for many years, All the courses I have been on, every single one of the manufacturers said to service only to the correct level as over filling will cause aeration of the oil even though many gearboxes have de-aerators. The aeration of the oil WILL cause premature failure and I have personally seen failures in as little as 2 hours after incorrect servicing of some makes of gearboxes. As for lower temps being indicated with overfilling? Well the temp bulb is supposed to measure the temp of the oil it's immersed in, if it's partly immersed in air due to aeration of the oil the indication cannot be correct. Think of the engine coolant temp if you lose coolant, the temp goes down because there is no coolant to read the temp of. Engine failure comes soon after. Just my 2 cents worth.

 

Manufacturers do not plan for heavy duty, commercial use of their gearboxes in light duty pickups. Ever heard of planned obsolescence? They want the things to wear out so they can sell new stuff.

I was a helicopter mechanic and maintenance pilot for 27 years, I know how wet bulb temp senders work. With my fast coolers what you suggest ain't happinin'. 97k+ miles on this tranny, over 60% towing, sometimes pretty heavy hasn't caused "premature failure". I have never had one last this long with the normal fill. And by the way, it hasn't failed. It's in the shop for preventative maintenance. It is way cheaper to get it inspected and repaired as needed than having an implosion 1200 miles from home. I've had two do that to me, both just filled to the bottom of the fill hole with syntorq. Your mileage may vary

 

Sometimes repairs of gearboxes don't make the same time interval if two were built on the same bench.. I have seen many large gearboxes on industrial machinery fail well short of their expected life while the unit next door runs well into its second hour interval (25,000 +). The rebuilt unit would then fail after only 10,000 hours.

While multiple rebuilds are a yard stick for comparison, its may not be telling the truth. Keeping the oil at its proper temperature, clean and free of air (don't use Lucas!) allows bearings/gears to live longer.

 

i found out whats in my tranny. it is a product called Synchomesh. dont remember who makes it but it was in a yellow container. is this the GM tranny fluid that is being recommended? thanks! ON EDIT: it was pennzoil. can anyone match up the part numbers?

 

Synchomesh is the GM product designed for differentials, it even has friction modifiers in it for limited slip rear ends.
I guarantee it will eventually trash your tranny.
I would dump that stuff ASAP and use the recommended products.