NV5600 transmission shifting problems

[PKnibbs]

I have a 03 Ram purchased used, 3500 4X4 6 spd with 225000 KM on it. I'm an X long haul trucker so know how to use a standard trans. It was used to pull a 26' 5th wheel (not on a reg basis) and now I pull a 33' 5th wheel and gross 20,000 lbs.



The trans gets very hard to shift when hot. Also when cold is still notchy but somewhat easier . I am contemplating a rebuild expecting syncros to be bad.



Trans shop says it may be clutch/pilot bearing related. New clutch Has 40,000 kms on it



I have replaced oil with recommended oil. . still same prob. Old oil was dark but not burnt.



I have heard that you should not tow in 6th gear as too much heat...



What trans coolers are there available for this trans?



Can some of you experienced folks help a guy out?

 

[JFlagg]

The only cooler I know of are the Fastcoolers for sale at Geno's. I don't know how much heat, but I have towed in 6th, though they have been fairly light(<8K lbs). I've read alot on these trannys and the common consensus seems to be it will always have that "notchy" shift feel to it regardless of what oil you use. I have stuck with the Penzoil syncromesh and it seems just fine. Search on here for other NV5600 threads and you'll find alot of info. All in all, its a strong transmission, with very few problems. It just has a rough feel, but it will last you forever.

 

[fest3er]

Do some research into a good synthetic lube. As I understand, a top-notch synthetic lube will allow these transmissions to shift a whole lot easier and smoother, and will significantly reduce friction, thus reducing heat. I think Amsoil is the best you can get, but you need to do the research and come to your own conclusion. And your research should start right here on TDR; plenty's been writ about the subject.

 

[fest3er]

Oh and, since this is your first post, welcome!

 

[Steve St.Laurent]

I moved your post to the 3rd gen forum where it belongs. If you look at the forum list you'll see explanations of what each forum is for. If you post things in their proper forum you'll get faster and more responses.

 

[Turbo_Bob]

I have the FAST Coolers on my NV5600, adds extra oil and disapates extra heat.

I only tow 7,000 lb box trailer and have no problems with the trans, at 94K. The trans has allways been hard to shift at times, cold or hot. You can not rush the shifting. I think thats why Dodge went to the G-56 trans on later models.

 

[Fast 1]

I've heard that you can add some mopar antislip for rear ends to the trans and it smooths out the transmission shifts. Maybe somebody could explain this better that I can.