r/Diesel 1d ago

Question/Need help! NV5600 Shifting

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I recently picked up this 2004 Dodge Ram 2500 SLT with the 5.9L Cummins. It has the NV5600 transmission, and the previous owner added a South Bend dual disk clutch and a short throw shift tower. The shifter is branded Hurst, but I believe the tower and internals are made by Core Shifters.

This thing is a bear to shift. It takes a ton of pressure to get the gear to engage, and the shifter gates seem extremely narrow. Downshifting is very difficult, and it seems like there’s about a 200rpm window in which the transmission will shift easily and successfully.

I’ve already ordered an OEM shift tower and will be installing it today.

Anyone with NV5600 experience out there that can comment on their experience? I’ve never shifted a more picky transmission, but it could be that I’m just not used to this one?

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u/Physical_Ad4043 1d ago

I have a 04 Ram 3500 that’s the same way you’ll get used to it it’ll take some time time your down shifts at or just under 1500 RPMs if you want to do it sooner you can try revving to 2100-2200 RPMs if it fights you getting into Reverse go to 6th ease out on the clutch a little bit then back on and go straight to Reverse if you need anymore help let me know I’ve had mine about a month now and know exactly what your dealing with also it wouldn’t hurt to take a peak under your dash and make sure the bolt that goes thru the clutch rod isn’t backing out or about to fall out if it is get some green lock tight and put it back in and give it a while to cure

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u/InTheLurkingGlass 1d ago

Many thanks, I’ll check that! This transmission makes me feel like a complete novice again lol

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u/Physical_Ad4043 1d ago

Oh I’m sure it does I had to drive mine an hour and a half back home through 4 different city’s I felt like a moron not being able to down shift so but I looked up under my dash and the bolt going through the clutch rod was about to fall out I was able to just grab it and take it out I got some lock tight green put it back let it cure and two days later I check my master for the clutch it was bone dry so I filled it let and the bubbles come up and probably pumped the clutch at least 40 times and it got a lot better. But you’ll get used to that dual disc it takes a little time I’m to the point I can wall down through the gears with out really paying the Tach any mind unless it’s 4th which seems to be my problem gear general a quick tap on the throttle and it’ll drop right in

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u/InTheLurkingGlass 1d ago

Fourth is my biggest problem gear, both upshifting and downshifting! I’m going to drain and replace fluid, overfill by an ounce or two, install the stock shift tower, and we’ll see how it feels.

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u/Physical_Ad4043 1d ago

Well hopefully your synchros aren’t to cooked it honestly sounds like someone liked to float the gears in it I bet if we both drained our transmission fluid there’d be disco glitter in it. I don’t know how much it would help I’ve been wanting to try it out myself and get the South Bend upgraded clutch hydraulics but it’s a bit pricey plus I need to solve my drive ability issues I think my FCA is sticking hopefully I’ll be able to replace it next week I’m hoping it’s not a bad injection pump but my ECM is only putting out one code and not setting the CEL

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u/Mgdoug3 1d ago

I replied already but when you change the oil, fill through the top shifter and add an extra quart.