I am looking to swap my auto into a manual. I was wondering if anyone knew which would be my best decision. Either the 5speed or the 6speed? Ive herd good and bads for both. I will be using it as a daily driver, towing trailer heavy loads, and also hook to the sled every once in awhile. I hope to be around 5-600 hp within the next year. Any information appriciated.. Thanks

 

The nv4500 had a nut that could come loose and strand you. Many get it tack welded in place.

The nv5600 is built for towing. The extra gear in between 2-3 helps keep the acceleration smooth without having to rev to the redline then bog it down as in the 4500.

Lots of talk about parts being unavailable for the 5600 hasn't rung true for me, my rebuild had evrything the next day.

The 5600 takes a specific gear oil and putting standard gear oil in it will trash it very quickly, beware if you are getting a used one.

Also, the 5600 shouldn't be towed in neutral, even a mile. The driveshaft needs to be disconnected, or you will trash it.

The 5600 is very heavy and a special tool is needed to remove it from the engine. no big deal, its available.

The 5600 isn't a sport trans. You shift it like a heavier truck, needing to give the blocking rings (synchros) time to sync. Trying to force them into gear just wears out the blocking rings early.

The weak link of either trans is the factory clutch. Get a good one like a South Bend. Its worth every penny.

I'm sure there is something I failed to mention but if you are going to tow, I'd get the 5600 hands down. I have towed with both and you can tell the difference.

Kurt

 

that nut is the 5th gear nut. it wont leave you stranded, many have driven over a year and many thousand miles without it. you just dont have 5th gear. you could get it welded, get the updated nut from dodge, or you can get a whole new fully splined shaft and not have to worry about it. parts for the NV5600 are going to be more expensive. if it were me i'd stick with the NV4500.

 

The NV5600 is built for towing and more HP/Torque. It does not shift quickly.
It is a much heavier duty tranny. A newer auto of some kind that is beefed up is proably better for racing.

 

I agree with everything SIXSLUG said except for these two:

Like cmac said, the 5th gear nut coming loose won't leave you stranded, you just won't have 5th gear.

I would really like to see the basis for not being able to tow the NV5600 in neutral. This makes absolutely no sense to me. How is towing it in neutral any different than slipping it into neutral while driving and letting the truck coast?

 

I did the swap from 5 to 6 speed and love it. The original 6 speed weighs 185 lbs. and the 6 weighs over double that. It is much stronger and has a much better spacing of the gears. Hated the 5 speed with the gap between 2 and 3, that is gone now. Wouldn't trade back for anything, love the 6 speed, it will handle the load real well. Been pulling 33K for about 250,000 miles with no problems at all. Started out running 75w90, shifted terrible, tried Mobil 1 engine oil for a while then Amsoil came out with their oil specified for the trans. It seems to work fine.

 

me too,

 

The only reason I can see not towing it is if the tranny is splash lubed only. With the engine off, none of the gears are turning to splash the oil around, just the mainshaft turning unlubed.

Just a few corrections to the info above. The NV5600 does not require a special oil. It runs a GL5 gear oil which is a 5w30 oil. The NV4500 DOES require a special oil. Its a GL4 oil which is a 75w90 weight. Like was said, losing 5th gear will not leave you stranded, more of an inconvienence. I put on over 1500 km with no 5th gear. I'm sure there are more that have gone much further.


You can also look into the G56. Its out of the newer trucks. I've got one stored, hopefully put it in my 12v this summer.

 

Sorry about the mis info on the 5th gear nut, I thought it was suggested not to drive it if this occured because it could get trapped in the gears and cause trouble.

I stand by my belief to not tow the 5600 in neutral. This was info obtained from my trans guy, the Dodge Dealer in Kalispell and the guy who towed my truck to the Dodge dealer in Kalispell. Reason: No lube is being circulated.

Also, I never coast my truck at speed in neutral.

The NV5600 does take a specially called out lube, at least to not void the warranty. Red Line and Amsoil both offer a gear oil specifically for the nv5600.
The factory offering is (was) supplied to Dodge by Texaco.

Since I got my new trans, it has shifted smoothly and gotten smoother. I continue to run the Dodge lube in it per the suggestion of my trans guy, just with an extra qt because I can!

Kurt

 

The NV5600 does require a special lube, according to the owners manual. Chrysler, Penzoil, Amsoil and maybe others have a special blend made specicly for this tranny(GN also has a similar blend that it meets). Seems others that have not used the "Blend" have had issues.

 

nv4500 needs an upgraded input shaft but the main shaft and out put shaft tend to be stronger than the nv5600. The nv5600 used to be thought of as the holy grail for Sled Pulling but the out put shaft tend to break more. there is a fix for it just like the input on the NV4500. I have also heard and experienced more main shaft issues in the NV5600 vs the NV4500. The NV5600 is the best for towing expecially heavy the spacing is great. For unloaded driving I prefer the NV4500. Just my .02.

 

Seems fairly generic. The MTG fluid listed on Amsoil's site sole application is the NV4500. Seems a bit more specialized. But I digress.

 

Thanks for all the info guys!! I think i may go for the 5600 if I can find one for the right price and also sell my 47re. Thank you!

 

Hi. Can come one clarify the transmission fluid between these two transmissions. I recently added fluid to my transmission which is only sold at the dealer. This fluid is Castrol Syntorq. This can only be sold (should be) at the dealer in quarts or in a drum. The quart size cost 23.00 () Really sucks on the price.

Amsoil, which I am planning to change to states it's for the NV4500. So,

for the NV5600, I was told that it doesn't need special fluid.

One of the reasons I want to get out of my NV4500 is because of high fluid

costs. (will be switching to Amsoil to lower my cost.)

 

I'd swap out my 4500 for a 5600 if I could. I've towed with both and the 5600 gears are great. 4500 gear spacing aren't terrible, but the 5600 is the superior of the two.