I spoke to the dealer today about some issues with my truck and I wanted to see what you guys may have experienced. I told them that my truck grinds when shifting into third and fifth when cold. He told me that he has spoken with New Venture and the NV5600 is set up tight from the factory and some miles on the unit should help. He also said that with the size and weight of the gears and the countershaft that it does take a second for it to quit spinning. Makes sense except that it quits when the fluid is warm which is when it is thinnist and causese the least resistance. I got under the truck and checked the fluid and it is about 2" below the plug. Second I told him that I have the rear axel howel and he wants me to bring it in and they will check the backlash. He said if that is correct that they are advised to tell people to live with it because it has to do with the cut on the gears. We will see how the trip to the dealer goes tomorrow. I just wanted some input from any of you who may have delt with this. Sorry for being long winded.

 

You didn't say how many miles you have on the truck but I presume it is pretty new. I wouldn't worry about the transmission at this point but do top up the fluid to the correct level. The transmissions do get smoother as you put some miles on it and cold fluid aggravates the problem. If it is still an issue at 10K I would go after them about it.

As far as the rear end whine goes, if there is a problem there it will get louder as time goes on. I complained about mine and they did nothing at first. But it kept getting louder and over a broader speed range. They finally replaced the ring and pinion which instantly corrected the whine. Only time will tell if the problem is permanently fixed. I had a discussion with the tech regarding axle fluid at the time of the repair and we decided to put in Redline 75W140 with some friction modifier for the break in. Up to that point I had been running the expensive DC stuff 75W90. I tow pretty heavy. Interestingly a recent TSB recommends the heavier fluid in the HD axles. Hope that helps.

Casey

 

I can't address the differential whine issue because mine are silent. That being said - they all should be silent. Don't let them say that all HD diff's (etc) make some noise. They don't. And you shouldn't have to listen to that kind of stuff.

When the dealer says those kinds of things, he's only addressing his warranty work bottom dollar concerns at the dealership. If he can convince you that its normal, that's one less headache for the day to be concerned about. You can bet your bottom dollar that if his or his wife's vehicle made that noise - he wouldn't live with it and it would be fixed in a heartbeat.

On the tranny issue, mine got real tough going into 3rd and 5th during the break-in period (whatever that is). At around 18k when I changed the differential lube(s), I also changed out the tranny lube. It made a world of difference, to the point where I'd say it was better than new. As far as what lube to use in it, there are lots of choices and threads on that subject.

 

The slight grind when cold is normal on these tranny's. First, top off the fluid and then try holding the clutch in a couple of seconds longer before shifting.