Engine/Transmission (1998.5 - 2002) Filling a NV4500

[KBalzuweit]

Is there any benifit to overfiling like there is in a getrag?? Is it good bad or just does nothing? Also anyone use those coolers you bolt on the side where the PTO cover is? TIA!!

 

[BDMiller]

Don't know about overfilling but I do have a temperature probe in my NV 4500. I have found that you really need to be in 5th gear all day to get the temps even up to 150. I don't think this thing is going to overheat so I doubt the fast cooler is necessary unless you are towing some seriously heavy loads. Curiously it does not get nearly as hot in 4th gear.

 

[TPlasek]

Are you going back with the stock Castrol fluid???

 

[BDMiller]

"Are you going back with the stock Castrol fluid??"



I switched over to Amsoil 2000 gear oil. I am not thrilled with it, shifting is a little harder. However it isn't bad enough to switch right now. Next time I change it I will go back to the Castrol.

 

[TPlasek]

I was asking because I put in Royal Purple 40k miles ago. Just recently the transmission became hard to get into reverse and fifth. I decided to start with changing the oil. To my surprise, the oil came out looking like the picture below. I was not expecting the fluid too look like this only after 40k miles. I took a sample and put under the microscope and looked to see what all the grey material was. They are very very small particles that don't even show up under the scope I was looking through. I then placed a very strong magnet close to the sample and I could see the few ferrous particles draw towards the magnet, but none of the grey particles were attracted to the magnet. This leads me to believe that the grey material must either be aluminum from a spun bearing race or the syncho pad material. After changing the fluid with 4 new quarts of RP the hard shifting into reverse and fifth has almost completely gone away. If anyone else changes their 4500 oil on a regular basis, I hope you will chime in and tell me how your oil looked after x amount of miles. This may be normal, but I was thinking of putting the Castrol in for about 20k and see how it looks. My only complaint about the Castrol stuff, is my original 4500 has the bearings go out at 100k. I know the history of the truck and it has been lightly used for the bearing to have failed. I then had no faith in the stock oil and went looking for something better. I still haven't read anything that states WHY the manufacturer states to only use Castrol. What does Castrol have in it that makes it different from other synthetics???

 

[DTroy]

The Castrol has friction modifiers in it for the synchros.



I don't vouch for any particular brand though. Everyone has a different opinion.



As for the failure of transmission bearings, it could have been lube contamination, incorrect shaft end-play, defective bearings, etc. .

 

[TPlasek]

Royal Purple has friction modifier already mixed in. This is one of the reasons I chose this oil. The grey material could be "junk" leftover from the original bearing problem that I didn't fully remove from the shifter rails. I'll check the oil again in a few thousand miles and see how it looks then. Except for the synchro pads, there is nothing different in this transmission then in any other manual transmission I have taken apart.

 

[JJ Jackson]

If you overfill a NV 4500 the gear oil will come out of the over flow tube and sometimes out of the shift cover. I know this because I took mine into a quick lube and this happened to me. The filler they used had almost the same size orifiice as the fill hole in the transmission, allowing it to be overfilled without the gear oil spilling out. They put the plug back in quickly, took my money, handed me the keys, and see ya! I got about ten miles away and the gear oil started puking out everywhere. About 3 weeks later I broke 3rd gear and also noticed no gear oil in transmission. I had blown the rear main seal. Gee, I wonder how that happened? What are you gonna do? Welcome NV 5600. BTW 5th gear heats up when pulling heavy. Lots of moving parts. Pull in 4th, direct drive. Get a Gear vendors Overdrive cuz pulling in 4th over dramatically reduces transmission heat.