CTD NUT

2500 RPM will not hurt a 5.9 ISB at all....that is within its intend operating range. These engines rattle away at 2500 rpm all day long in tractors, medium duty trucks and stationary gen sets everyday. EGT and load will be notably lower in 4th gear instead of 5th when hauling heavy. With lower cylinder pressures because of less load, you will likely have less cylinder leak down which will mean cleaner oil for sure anyway. 2500 RPM will not compromise the longevity of the engine considering load will be reduced in 4th.

haloman

Remeber, you can always find a smarty in the classifieds for cheaper than retail.

safehaul

WOW.. this is really making me feel even better about this plan. With all the ATS mods we have been fighting EGT going up hills... so this may help out.. I even installed a large warning light that goes off when you hit 1300 degrees so that my driver(s) have no choice but to back off or stare at a bright red light in their face. I gotta think some guilt kicks in if they hold it there

The truck has a race inj pump, FASS, injectors and a Edge.. the edge is incredible with all these mods. but we keep it on 1 per Edge for towing.. at least I hope we do... Sometimes I wish I had hidden the edge... but as I told him.. if he messes with the edge and goes into high EGT's he will be walking home.. so I think I am ok.

Thanks for the info re rpm's.. I just didnt know if it was ok to run this many r's.. I think the truck will pull better and more consistent in 4th so it may actually extend the life of the motor.. he used to let it lug down before he shifted into 4th.. and that is what rattles that 5th gear to death I think...

I wonder, could I just have Aamco remove 5th? That way I KNOW nobody is using it.. My next though is I would go with some very cool 19" Rims in the rear and drop the rpm's by 200... tires would last longer! thoughts?

safehaul

Hey there is a 5600 in classifieds.. virginia which is an easy drive from here.. $500 and needs synchros.. could I do the syncros myself? Any special tools needed?

CTD NUT

I have no experience rebuilding an NV5600 but I'm fairly sure there are some special tools to do a rebuild. Regardless, a good 5600 core is worth at least triple that so, I don't see how you could go wrong with $500. A complete rebuild of an existing 5600 should probably be around $1500 and you might even be able to do better. I would contact your tranny guy for a quote but $500 is a steal any way you slice it!

safehaul

Ok.. thanks.. I'll see about buying it.

mwlu711

do you know this for a fact.i ask because dad has one and i would hate for him to need parts and not be able to get them.also i would realy like to use one in a future project.

CTD NUT

NV4500's and 5600's are no longer offered in a production vehicle but there are still hundreds of thousands in service. Currently, parts and service are not an issue for either transmission.

Valv

Actually I was reading on Quad4x4.com there has been a lack of parts for the 5600 and some 2005 in warranty trucks are stalled in the shop waiting.
I was thinking about a 5600 too but I decided to hang on to my 4500 after reading that.

AggieJustin

This is been my understanding as well. When they shut down production of the NV5600 unit, no one picked up and started making replacement parts for it. It would be nice if someone in the aftermarket would start making parts so that maybe repair prices for the 5600 could get to reasonable levels.

CTD NUT

Hmm...I'm at a loss...there doesn't appear to be an issue in this part of the world with the aftermarket supporting the 5600.

safehaul

I'll look for a rebuild kit first.. if I can't find one I wont buy it.


Edit: yep.. everyone seems to be OUT of the syncro's... ou can get bearings and seals.. but syncro's is a no go.. WOW that sucks for 5600 owners.. I still might buy it and hold out for a kit.

AggieJustin

I'll follow my remarks with the fact that I haven't personally gone looking for parts, I'm speaking from people's experiences posted here and what I've seen online.

I know the Quad4x4 website had statements that their access to a supply of new NV5600s was exhausted and replacement part availability was marginal at best. But it also referred to things possibly getting better in 2007, so I'm not sure of the age of that info.

Valv

I would look into the 3rd gen 6 speed transmissions or a Med Duty .

safehaul

New thought.. using 4th gear 1:1 why not go with single 22.5" wheels and tires in the rear (not duallies).. those are rated for like 10k each tire arent they? each half inch is good for about 50 revs.. I dont know how tall they would be but I would think I'd gain a few inches at least.. so 200 revs minimum.. those tires are good for like 150,000 miles too..

I would think the weight of a single 22.5 vs dual 16" would be close..

crazy idea?

BTW.. here is my load from hell 29,950 lbs.. OUCH