Well I am soon to be rebuilding the trans in my truck. I have rebuilt a couple of NV4500s and a few other manuals but never a NV5600. I keep hearing how the 5600s are hard to rebuild but I don't quite understand why. Anyone want to clue me into why they are so hard to rebuild? And please don't try to tell me I need 100T press to press the gears off. That has got to be the biggest load of crap I have heard about these transmissions. You may have the occasional trans that needs a little extra help but otherwise a 25T should have no trouble getting the job done.

i have never built a tranny. that, the 100 ton press and some special tools i read about stopped me from even thinking about it. but if it turns out fairly easy, i have got one in my shop to work on. i'd be interested in seeing what you find out and how it goes.

I've got the "necessary" special tools from Miller spx and a 25T press. I just really don't see how, if your properly using the press, it would take 200,000LBS of force to remove the gears from the shaft.

Blueox who is in and out here at times knows a fair amount about the nv5600. you might be able to pm him and pick his brain.

IIRC, none of the gears are "keyed", so a "BIG" press is needed. Especially moreso because the NV5600 is a true "truck" tranny. That's why it's so heavy.................400+lbs. That's all I have to say on it.

NV5600 6 Speed Specifications:

Case:......Cast Iron

Bellhousing:......Aluminum Alloy

Torque Rating:......550 lb.-ft.

Gross Vehicle Weight:......16,000 lbs.

Gross Combined Weight:......26,000 lbs.

Transmission Weight:......360 lbs.

First Gear Ratio:......5.63-1

Second Gear Ratio:......3.38-1

Third Gear Ratio:......2.04-1

Fourth Gear Ratio:......1.39-1

Fifth Gear Ratio:......1.00-1

Sixth Gear Ratio: .073-1......(Overdrive)

Reverse Gear Ratio:......5.63-1

Oil Capacity:......9.5 pints

Oil Capacity with optional filter:..10 pints

Recommended Lubricant:.....Chrysler 4874464

Input Shaft:..10 Spline, either 1.25" or 1.375"

I believe that the was a NV5600 that was also rated for 650 ftlbs input torque in other then Dodge applications. Here is a link for info on the NV4500 http://en.wikipedia.org/wiki/New_Venture_Gear_4500_transmission

If you notice the NV4500 is rated at only 1500lbs less GVW then the NV5600. While I most certainly agree that the NV5600 is a more robust transmission, its still only a pick-up truck tranny, not a eaton fuller 13spd gearbox.

While gears that are splined are typically a tighter fit then gears that are keyed, I still am going to need proof that it takes 100Ts to push the gears off.

I'm not trying to argue with anyone. Just trying to gather facts, so if I am wrong someone please tell me about their first hand experience with rebuilding one of these transmissions.

Well I am soon to be rebuilding the trans in my truck. I have rebuilt a couple of NV4500s and a few other manuals but never a NV5600. I keep hearing how the 5600s are hard to rebuild but I don't quite understand why. Anyone want to clue me into why they are so hard to rebuild? And please don't try to tell me I need 100T press to press the gears off. That has got to be the biggest load of crap I have heard about these transmissions. You may have the occasional trans that needs a little extra help but otherwise a 25T should have no trouble getting the job done.

Why are you rebuilding your NV5600? Do you have a 4x4?

Blueox01, When I changed my trans fluid it looked like there was a glitter factory hard at work inside and yes I have a 4x4. Not making any noises or giving any problems but I like to be proactive on things.

Blueox01, When I changed my trans fluid it looked like there was a glitter factory hard at work inside and yes I have a 4x4. Not making any noises or giving any problems but I like to be proactive on things.

Change the fluid,Penzoil makes Sychromesh that meets spec for NV5600(half the price of dealer) Manual call for 5 qt's put 6 qt's in.

I run 6 qts of royal purple synchro-mesh and change it every 50k. With 245k and the fact that there was not that much metal in the oil last time it was changed, I have a feeling I'm getting close to a rebuild. I understand the concept "if its not broke don't fix it" but I don't like running stuff to complete failure nor do I like be stuck on the side of the road.

I know you can by bearing kits online,like off Ebay for $500-$600. I've Replaced the rear bearing,but from my research this is a tranny I would'nt try to rebuild myself.

Change the fluid,Penzoil makes Sychromesh that meets spec for NV5600(half the price of dealer) Manual call for 5 qt's put 6 qt's in.

did you ar have ever used anti slip in the oil? i have read a few threads wher people recomend it. just dont know what to think of it.

Dripley, I have run royal purple in the trans since it had 55k on it. I have only towed about 50K and it ranged from 10ft Jon boats to my 30' GN. The rest of the 150k I put on the truck was running from MS to NY and from MS to FL. I have never had any issue from my trans.Blueox, Research is what I am doing now and so far people have said "yea you need a 100T press" and "yea NV5600 are hard to rebuild" but no one has chimed in with any real experience on why. I mean the absolute worse case scenario is that I have to take it to a shop with a large enough press and have them press the gears on and off for me.

i have towed about the same as you. move my rv about 5 or 6 times a year. the owners manual states to keep the fluid topped off and you dont have to change it. i beleived them. but i did get behind on the fluid. so my problems are pretty much self inflicted. started haveing trouble about 205k with 1st and reverse jumping out of gear. then one day it stuck in 4th and had to force it out then it would not go back in. replaced it with one from a junkd yard. all new penzoil with an extra quart. would like to buld my spare but it is gonna be over my head. wrong tools and no time.Have heard of adding some anti slip for the synchros, just dont know if it is really benificial or harmful.i agree with the proactive part, but it seems every time i try, something else blindsides me. even with what i have spent i am still satisfied with what i have and do not want to buy a new one.

Well chllngr528 I would have to agree with you about the 100 ton press that is over kill! When I was younger I worked in a tranny shop and we had a 20 ton press that worked great on anything from small pickups to one ton trucks. I also just a few years ago helped a buddy build a T56 for his Camaro and we used a 20 ton press and it worked great. The only thing that I know about the NV5600 is that the parts are hard to come by if you need any hard parts. I say go for it and good luck man!!!

Blueox01, When I changed my trans fluid it looked like there was a glitter factory hard at work inside and yes I have a 4x4. Not making any noises or giving any problems but I like to be proactive on things.

Mine was that way when I bought it. Was in the 100k range then. I changed the fluid using Pennzoil Synchromesh. The problem was less at the next change (15k miles), then at the next there was no noticeable metal flakes. After that I began using Redline MTL and running 30k miles. The truck is at nearly 300k now and the transmission still goes. My 3rd and 5th synchros are about shot but if you are patient it will shift or you can double clutch it into gear. Before you go through the trouble of attempting to rebuild such a large transmission I would certainly attempt to flush it a couple times and see if the glitter problem goes away. It could very well be material from the dogs getting ground. However if you do decide to go ahead and rebuild the sucker then check this link out. http://dodgeforum.com/forum/dodge-cummins-diesel/112548-diy-transmission-work-nv5600.html Good luck

Did you ever rebuild? I have my 5600 out and debating rebuidling it. 129k, brass in oil, but no noise.