Engine/Transmission (1998.5 - 2002) Making the NV5600 shift smoother/faster

[sparks57]

First of all, it seems like half of the guys around here say their NV5600 shifts like crap, and the others say it shifts just fine... Is the shifting inconsistent between transmission to transmission, or are some guys just not able to get used to them?



I've heard different lubes can help, but can you do anything else? I do understand that the NV5600 is a big transmission, and the mass it's self is one of the biggest barriers... but I've also heard of syncro problems?



And what do you guys think about the short shift kits? Is any one any better than another? I've onyl heard anything about the BD kit.

 

[Gary - K7GLD]

General shifting quality of the 5600 will normally vary SOMEWHAT from one truck to another - if severe difficulty shifting is encountered, there may be a transmission or clutch issue...



Keep in mind these are TRUCK transmissions, NOT sportscar trannies, and shifting characteristics WILL be different from a passenger car. Some owners have experimented with alternate transmission lubes, some have noted what they consider significant improvement - but time and miles seem to be the most consistent "fix"...

 

[JaMan]

Mine shifts like crap! No really it is notchy and always has been and it has been Amsoiled.



Hope you find some awnsers,



Jared

 

[Joseph Donnelly]

Mine shifts well, but the NV4500 was smoother. Many of us "graduated" from that 5 speed and miss the smoothness. Fresh lube helps, and I think the Redline MTL made it shift a bit better than the spec'ed Pennzoil stuff.

 

[darkhorse]

My 6 speed has always shifted very well. It's only got about 50K on it. I had Amzoil gear lube put in along with my clutch swap last week. It's still smooth but I really haven't noticed any difference from the original fluid. I've got the BD short shifter & it also works for me very well. I've only driven one 5 speed truck & that only a few miles. It wasn't much different from my 6 speed. It sounds like they can vary a lot.

 

[CumminsFarmer]

My 02 shifts fine with 90k miles. I do notice that shifts a little tougher than my uncles NV4500, but its not much worse. Im not an expert by any stretch of the imagination, but I dont believe in the short shifters at all. If your having trouble shifting now, then the last thing you need to do is try to jam into gear quicker. They're not tractor transmissions, but they shift kinda like them. Remember that when you "grind a gear" your grinding that tiny little brass ring in the sync assembly.

 

[Cummins Pilot]

45k on mine and its got the generic Mopar fluid. Shifts good. No complaints. I'd like to get the BD short shift sometime soon. I just like the shorter throw and how it brings the stick a bit closer to the driver. I'm not looking for speed shifting.

 

[PCarbonaro]

My 6 speed shifts fine, except when cold; then the 2--->3 shift grinds. When it warms up, the grind goes away. But it does bug me, since I think I'm doing damage. So I don't know if this is "normal" for a cold NV5600 transmission, or if I have a suboptimal unit.

 

[CRSmith]

Technique helps.



To upshift: I depress the clutch w/ my foot still on the gas. This runs up the rpm a couple of hundred in its no-load condition. Then, let foot off gas while egaging next gear and letting off clutch. The rpms will fall neatly in line with what the transmission wants.



To downshift: I double clutch all the time to match rotation speeds.



It takes practice.

 

[RW]

mine shifts great, for a truck. i changed the fluid out at 20k (mopar). now have 31k. short shift works great for me.

 

[Fred Swanson]

Change the fluid about every 20K miles. You can actually tell a difference, and just about the time I feel it getting harder to shift, it's time to change again.

 

[MRiley]

Having driven sports cars and "Big" trucks. I can tell you that the shift quality of the 5600 is much more like that of a rig. The 5600 is a big trans and there is a lot of stuff to move. I find that running up the rpms really helps make the shifts more smooth. I always bump the throttle between shifts, especially when the truck is cold. I really helps on the down shift too. (5 to 4 or 4 to 3)

 

[Hohn]

Mine shifts well, but the NV4500 was smoother. Many of us "graduated" from that 5 speed and miss the smoothness. Fresh lube helps, and I think the Redline MTL made it shift a bit better than the spec'ed Pennzoil stuff.

I suspect that the shift quality of the 5600 is hampered by the heavy rotating assembly that must be manipulated by the synchronizers. General rule of thumb-- smaller clutch=smoother shifts.

jlh

 

[Gary - K7GLD]

My 5600 has always shifted acceptably - very well when warm, and only the slightest tendency to "grab" a tooth between 2nd and 3rd but no grind - always made a big difference if I simply slowed my shifts a little.



BUT today I made the time to drain the stock transmission lube installed 30,000 miles back, LOTS of towing, and was pleasantly surprised to see the stock lube appeared as clear and clean as when it came outta the bottle!



SOooo - anyway, I installed 4 quarts of Redline MTL, and tomorrow wll get a chance to see what, if any, changes I see in shift quality...

 

[BWillard]

Mine really don't like to shift from 3rd to 4th when cold (major grind) and from 5th to 6th I have to let it go completely to idle so it won't grind even when warm! Downshifting it gets worse, 6th to 5th OK, then if I want to downshift from 5th the truck HAS TO BE under 20MPH! Alot has to do with the DD EEP but, I would never go back to my auto. :-laf

 

[Radshooter]

Mine started out shifting tight and is loosening up the more I drive, or I am getting used to it. I still get a little stutter on a cold 2-3 shift, but it goes away when warm. If I take my time, it shifts OK. Shifting this transmission reminds me of shifting my Dad's big wheat truck back on the farm.

 

[sparks57]

Thanks for the input guys... looks like good lube and some break in miles are all you can do.



I just thought I read somewhere that somebody did something to the NV5600 internally to make it shift better... ???

 

[PKleine]

Having driven sports cars and "Big" trucks. I can tell you that the shift quality of the 5600 is much more like that of a rig. The 5600 is a big trans and there is a lot of stuff to move. I find that running up the rpms really helps make the shifts more smooth. I always bump the throttle between shifts, especially when the truck is cold. I really helps on the down shift too. (5 to 4 or 4 to 3)

I second the idea that the NV 5600 shifts like a truck transmission. I too have driven 'big' trucks and sports cars, for a truck transmission the NV-5600 shifts rather well. If your experience is only with light duty/sports car like trannies, then you may not appreciate the shifting qualties of the NV-5600.



Bumping the throttle or matching rpm's, really does help shifting and reduces wear & tear on the clutch and drivetrain.



I found that Redline MTL helps, but also make sure that you don't have too many floor mats or a miss-positioned floor mat that keeps the clutch peddle from going completely to the floor. I found that by removing one of my floor mats (I had three for some reason ) the shifting immediately improved.

 

[SDisley]

As a big truck driver with close to 2million miles driven without a transmission or clutch failure, I only use clutch from a dead stop and my NV5600 works very well for up shifts and down shifts.

 

[Alphacowboy]

I have a NV4500, but I rarely use the clutch past 2nd gear... there is nothing wrong with that is there? I jest barely let of the gas and it flows right into the next gear (98% of the time) when I pull/push the shift lever. I usually have to use the clutch to get to 2nd from first though (actually have to use 1st due to 35" tires and stock 3:55 gears) Also, I dont feather the clutch either, I just let go, except first, I do feather it, but only slightly... and I mean slightly. This is my first manual vehicle, and I must be doing somthing right as I am nearing 90k miles and I bought it with 64k in Febuary, so I havent burnt up the clutch yet... :-laf Just wondered how many of you not use the clutch and if this is good practice or not.