Ok I'm thinking about swapping the 5speed in my 2000 to a 6speed. Which would be a better one the nv5600 or g56. Also what would i need to do the swap. i imagine a bellhousing, and i will put a dual disk in it. But will i need to modify the crossmember any. Thanks in advance for any help.

 

Thats sweet Wish I had a 5 or 6 speed

 

A NV5600 has cast iron cast which makes it a little sturdier. However parts are expensive for them. The G56 has an aluminum case and a numerically higher overdrive(engine will spin faster at the same speed.) The 5600 shares the same 1,2 and direct (4 in 4500 5 in 5600) and over drive with the 4500.

THe 5600 has an integrated bellhousing(believe the g56 does too). Being that you have a 2000 that should have the wide crossmember with the two sets of slotted holes. The 5600 will use the back set. The 4500 and the auto use the front set.

You will need to get you driveshafts modified as ther is about 5.5-6 in ifference in the 4500 and the 5600. You will need a new clutch and flywheel but if your going to put a dual disk in it you will have that covered.

Most of my experience is with the 5600. I don't know much about the g56.

 

Will the bellhousing for a g56 and a nv5600 fit my 2000 is my main concern. Also what is the weight difference between the two. And by saying the g56 has a higher overdrive this would allow me to run higher speed at lower rpm correct.

 

Yes they will both fit. The cummins uses the same pattern through its model run( at least the 5.9 don't know about the 6.7)


nv5600 weighs 360 lbs
nv4500 weighs 250
g56 weighs 225-250

Practical application? I can pick up a 4500(barely) and set in the back of a (low)truck by myself. Wouldn't even consider it with the 5600.

NV5600 ratio's

Gear Ratio
1st 5.63
2nd 3.38
3rd 2.04
4th 1.39
5th 1.00
6th 0.73
R 5.63

G56 ratio's

FIRST
5.94
SECOND
3.28
THIRD
1.98
FOURTH
1.31
FIFTH
1.00
SIXTH
0.74
REVERSE
5.42

NV4500 ratio's


1st 5.61
2nd 3.04
3rd 1.67
4th 1.00
5th 0.75
R 5.61

The overdrive ration on the G56 is .79 and the nv5600 is .74 so you would be running at a higher rpm in the g56 to go the same speed as the nv5600. Also the g56 is overall geared lower. So if your truck has 3.55 gears now it will drive more like it has 4.10s.

Also the nv5600 requires a starter spacer(should come with the DD) and the g56 needs a different starter from a g56 truck in order for it to work.

*all info in this post was collected off the internet and may be wrong

 

ok maybe im going about this the wrong way im looking to move to a 3.73 rear end because these 3.55 suck for pulling and everyday driving. But i dont want to give up the fuel economy i get on long trips with them.

I looked at a overdrive set-up but not sure a gear-vendors or any others would hold up that well aslo thought about a two speed rear end.

Am i chaing the right rabbit by thinking a tranny sawp or is there another route someone would suggest.

 

A 6-speed swap will make it a little nicer to tow with as the gears are spaced closer together. Since the overdrive is the same on the 5600 you shouldn't loose much for fuel economy( just a bit of extra weight.)

Doing some quick figuring a g56 with 3.55 gears is a 2.8 final drive ratio. A nv5600/4500 with 4.10 is a 2.9 ratio. The 5600/4500 with the 3.73 is a 2.7 w/ 3.55 it's a 2.6

So the g56 with the 3.55 gears would have an overdrive ratio that is lower than a 4500/3.73 but higher than if you switched to 4.10s.


The gear vendors overdrive would help because you could split your gears (like a 6-speed) and still have the option of a double overdrive should you choose to use it. Though you wouldn't use it much when towing. They do make a model designed for diesel engines. But since it installs after the t-case you could only use the splitting feature in 2wd.

The gear vendors and the 5600 swap would be the least amount of work. However as I mentioned before, 5600s are expensive. The g56 would require more work and give you a lower gear.

A gear swap would probably be the cheapest(depends on who does it, if you buy new gears, ect.) but setting up gears can be a pain.

 

im going to do the same thing to my pickup and i want to put the g56 in it for better towing and less weight