NV4500 upgrade?

[Drebs]

Hey guys I'm new to all this, Just bought a 1997 5.9 12 valve 3500 2wd dodge ram dully standard with 160,000 miles on it. I have the dreaded 3rd gear grind,(changed the transmission oil to 75-85 syn gl-4, still had same prob) I've read of guys putting new ones in and it happening again 300 miles later. My transmission guy quoted me 1,750 to drop it out give it whatever it needs and put it back in..

Here's my question I use is to haul lumber (tow heavy, as heavy as i can go) can I upgrade to a better transmission(one that doesnt have notorious gear problems)? nv5600 or g56. When I bought this I was expecting it to go 400,000 miles now that I have to do this I don't want to do it again in another 160,000 or less... any advice on the best corse of action or whether a good rebuild is better than new idk.

Thanks , Drew

 

[GAmes]

After replacing or repairing my NV4500 12 times I upgraded to a G56. It has gone over 400k miles, with only a front bearing needing replacement one time.

https://www.turbodieselregister.com/threads/221115-Mission-G56-(pictures)?highlight=mission G56

 

[Drebs]

Awesome this is exactly what I was wondering... does it have to be year specific found one on eBay listed for 2005-2015, do I have to find one for 97’ and I can go from the 5 speed I have to 6 ? No big conversions. Also what price range I’ve found one on eBay for 2,400 and some dyno tested from Midwest for $4,200.

 

[Shadrach]

Awesome this is exactly what I was wondering... does it have to be year specific found one on eBay listed for 2005-2015, do I have to find one for 97’ and I can go from the 5 speed I have to 6 ? No big conversions. Also what price range I’ve found one on eBay for 2,400 and some dyno tested from Midwest for $4,200.

The G56 came out in 2005.5 so that covers almost all the years. They changed the gear ratios in 08. It is refereed to as the "AE" version and the earlier one is the "AD". These are the last part of the Dodge part numbers.


The G56 is an Aluminum cased transmission and the NV5600 is cast iron.


The NV5600 will fit with no problems are it was used in that body style, altho I believe you have to get the correct transmission cross member. Check out the gear ratios between the different models. If you are going with the NV5600 get one from as new as possible a model year as you will want the 1 3/8 " input shaft. It's stronger o course. The G56 won't take a lot of extra horse power as some have split the case open.

 

[Drebs]

The G56 came out in 2005.5 so that covers almost all the years. They changed the gear ratios in 08. It is refereed to as the "AE" version and the earlier one is the "AD". These are the last part of the Dodge part numbers.


The G56 is an Aluminum cased transmission and the NV5600 is cast iron.


The NV5600 will fit with no problems are it was used in that body style, altho I believe you have to get the correct transmission cross member. Check out the gear ratios between the different models. If you are going with the NV5600 get one from as new as possible a model year as you will want the 1 3/8 " input shaft. It's stronger o course. The G56 won't take a lot of extra horse power as some have split the case open.

So the nv5600 is better ( more reliable than the nv4500)? In terms of realiability? And the notorious 3rd gear grind not a prob on the 5600?

 

[petersonj]

So the nv5600 is better ( more reliable than the nv4500)? In terms of realiability? And the notorious 3rd gear grind not a prob on the 5600?

I have no experience with the NV4500, but I have 290,000 miles on my NV5600 with the original clutch and it is still going strong.

Any manual transmission can suffer from gear grind (worn synchronizers) by poor driving habits, such as driver not matching engine speed to road speed during shifts. I am not saying that this is what is happening in your case, but if a transmission has a weak synchronizer, the symptom of grinding gears will show up much sooner with poor shifting habits.

Whichever six speed you pick, you will be very happy that you made the conversion.

- John

 

[Drebs]

I have no experience with the NV4500, but I have 290,000 miles on my NV5600 with the original clutch and it is still going strong.

Any manual transmission can suffer from gear grind (worn synchronizers) by poor driving habits, such as driver not matching engine speed to road speed during shifts.

I am not saying that this is what is happening in your case, but if a transmission has a weak synchronizer, the symptom of grinding gears will show up much sooner with poor shifting habits.


Whichever six speed you pick, you will be very happy that you made the conversion.

- John

Ok just talked to a buddy who’s a dodge Cummins fanatic I’m going to make the switch to the n5600... https://www.ebay.com/i/282613245328...3D711-117182-37290-0%26rvr_id%3D1494671696295

Will this fit my 97’ from what I’m finding the nv5600 was made for later year models and if putting in a 97’ you have to get a adaptor bracket made as it’s bigger than the nv4500. Anybody have any idea what I’ll be charged and much adaptation is required over putting in Nv4500.. thanks I appreciate the help

 

[petersonj]

I really don't know how difficult or costly it would be to do the conversion. You may want to search the forum for someone who has already done this. Also Cummins or Southbend Clutch may be able to help you. Make sure the NV5600 has the 1 3/8 " input shaft as mentioned above. The larger input shaft uses a 13" clutch.

You may have to replace the hydraulic portion as well, since it will be operating a larger clutch than with the five speed.

You will probably have to modify the length of both front and rear drive shafts.

There will be plenty for you to do.

It has not been mentioned here, but you will enjoy the extra gear as the six speed transmissions are much more suited to enhancing the performance of the Cummins engine. The close ratio transmission keeps the engine in its best operating range and gives you a proper gear for almost every driving situation. - John

 

[GAmes]

If you read down a few posts you will find the gear ratio numbers of all the transmissions. I have an AD model G56 out of a 2006, if you want a higher speed overdrive 6th gear you would want the AE model. I think the AD is perfect for towing with my 3.5 differential.

The NV5600 was installed in lower HP trucks than the G56, and isn't as strong IMO. The G56 has been used in medium duty Mercedes trucks for quite awhile. You can research the splitting aluminum case issue. I think you will find that it is only an issue with really high HP engines either racing or pulling sleds. Both transmissions will require a means to make the speedo work. Dakota Digital has upgraded their interface module, so the directions I gave for setting it up are now obsolete, but all you need to do is call them. You might want to check on the availability of NV5600 parts before you make your decision. They have been out of production for over a decade. If you read the fine print of the ebay link you will see the core charge is $1500, which makes that transmission very expensive since you don't have a core.

Besides the transmission cost you will need a driveshaft, which for the NV5600 might be found out of a parted out truck. One for a G56 requires yours to be modified. South Bend Clutch can fix you up with a flywheel, clutch and PP for either setup. IIRC my kit was in the $1000 range, but that was 8 years ago.

As has been said, a 6 speed is a lot more towing friendly, and both transmissions are far away better than the NV4500. Conversions to both transmissions have been documented on line numerous times, so finding out the small details is pretty easy.