Dodge Cummins Diesel Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
Hello.
I have a 04.5 2500 4x4 with the NV 5600 6 speed manual that I use to pull our 32 foot fifth wheel. I've only pulled the trailer 3 or 4 times yet, but from the beginning, it seemed like as soon as it got hot, the transmission was almost impossible to shift. It shifts excellent all the time when I'm not towing, only has trouble when pulling heavy.
After reading up on it, I changed out the trans oil and used Royal Purple synchromax oil. Still sticky. After reading some more, I dumped in an extra quart through the top of the trans, and this made it a little better, but still sticky. After that, I found some knockoff pod-type trans coolers from ebay. I was impressed when I got them at what good quality they seemed to be, so I installed them and filled it up, once again removing the shift tower and adding an extra quart. All tolled, I think it now has 8 quarts in there.
Took it out for a hundred mile spin pulling the trailer on a cool day the other day, and it's definitely WAY better, but still fairly sticky feeling when it's been pulling hard, up hills and such.
One of the pod coolers has threaded holes with plugs in them, so I was considering plumbing in a oil cooler with a little pump to circulate the oil.
If anybody has any advice about this transmission, I'd like to hear it.

Cheers
Bert
Automotive tire Trunk Vehicle Motor vehicle Bumper
 

·
Registered
Joined
·
3,583 Posts
You're going about things the correct way. You may want to contact https://supersticktransmissions.com/. They are the go-to experts for the NV4500 / NV5600, and can likley offer you some advice on next steps.
 
  • Like
Reactions: tryNto
Joined
·
3,771 Posts
What do you mean by sticky?

What clutch is in the truck?

It is strange that you are only having shifting problems only when the trans is hot.
The NV5600's do run really hot when towing but that's normal.
I don't think I've even heard of a hard shifting NV5600 only when hot, including my 2004 NV5600.

Original clutch hydraulics in the truck? I wonder if the clutch master or slave are getting weak when hot.
I think I would try pouring very cold water on the clutch master and clutch slave when the trans is hot and hard shifting.
Cool them down while keeping the trans hot.
Easy to do, worth a shot.

If you can find a "little pump" to move hot gear fluid through a cooler, you are the only one!
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #4 ·
I have no idea what clutch is in the truck, I bought it with 165000 miles.
The clutch works smoothly, engaging and disengaging at the right places, never feels any different no matter the temp.
When the truck is empty, the trans shifts as smooth as butter all the time. It only starts to get sticky when pulling heavy for a while. By sticky, I mean that it wants to "stick" in gear when I go to downshift, then the shifter feels very stiff when moving it around between the gears. Just generally hard to shift. the feeling of the clutch never changes.

As far as finding a pump goes....
I'm not sure what you mean by me being the only one.
Would something like this not work?
 

·
Registered
Joined
·
1,749 Posts
Install a transmission temperature gauge, sensor goes in one of the PTO plate holes.
EDGE CTS is the easiest to set up, digital so it is accurate. Gives you a great gauge package that doesn't take up the whole cab and dash
Take trailer out on hot day, if tranny lube temperature not over 250d F, tranny temperature is NOT the problem
Most likely worn parts in the 5600. The top main shaft gets poor lube flow in these, so does rear main shaft bearing. Several mods for these that require machine shop
Superstick ONLY for a rebuild.
Put in a HD organic single disk Valair or SD kit with new flywheel and their HD hydraulics so you don't end up broke down on the road with that large RV

 

·
Registered
Joined
·
11 Posts
Discussion Starter · #7 ·
Install a transmission temperature gauge, sensor goes in one of the PTO plate holes.
EDGE CTS is the easiest to set up, digital so it is accurate. Gives you a great gauge package that doesn't take up the whole cab and dash
Take trailer out on hot day, if tranny lube temperature not over 250d F, tranny temperature is NOT the problem
Most likely worn parts in the 5600. The top main shaft gets poor lube flow in these, so does rear main shaft bearing. Several mods for these that require machine shop
Superstick ONLY for a rebuild.
Put in a HD organic single disk Valair or SD kit with new flywheel and their HD hydraulics so you don't end up broke down on the road with that large RV


Thanks for this. I'm gonna call SuperStick today.
I am almost positive that my trouble is at least partly heat related, because of how much better it is now with the added capacity and cooler pods. I'll see what the trans shop over in Texas has to say about my troubles.
Bert
 

·
Mod-Admin - Not a Newb in 3rd Gen only
Joined
·
14,016 Posts
Font Automotive exterior Window Screenshot Art


Don't forget to report back with any info that might help yourself and others.
Font Symmetry Magenta Circle Event
 
Joined
·
3,771 Posts
I have no idea what clutch is in the truck, I bought it with 165000 miles.
The clutch works smoothly, engaging and disengaging at the right places, never feels any different no matter the temp.
When the truck is empty, the trans shifts as smooth as butter all the time. It only starts to get sticky when pulling heavy for a while. By sticky, I mean that it wants to "stick" in gear when I go to downshift, then the shifter feels very stiff when moving it around between the gears. Just generally hard to shift. the feeling of the clutch never changes.

As far as finding a pump goes....
I'm not sure what you mean by me being the only one.
Would something like this not work?

Certainly a strange issue. I still recommend to try a few things with the clutch hydraulics before condemning the trans.
Looking forward to any info that Superstick provides.


As for a gear oil pump, when you said "a little pump", I was thinking a cheap little pump!
There is no such thing as a low priced quality 12V gear oil pump as your links show.
If you can find a kit that can handle gear oil, (not ATF or light oils that imports use) and an adequate cooler for a truck, it all starts adding up, getting very pricey, plus the added complexity and added failure points.
Plus you would need a trans temp gauge to monitor the cooler.

Hopefully nothing serious with your trans.
 
  • Like
Reactions: tryNto
1 - 9 of 9 Posts
Top