cbrahs

I have the opportunity to do a tanny swap (if everything goes right with the dude).

For those of you that have the manuals, give me your opinions. Future plans for the truck are long with a good deal of HP (twins, studs, injectors, dual cp3, cam, springs, damper, double disc clutch, etc...). I want to do this once and not have to worry about the tranny. Heard people love their G unit and other say it won't hold up to High HP due to the aluminum flexing and putting undue load on the shafts and bearings.

COME ON GUYS. what to do. (this swap aint gonna cost me a thing but a clutch and my time)

Bswope

DO IT !!!!!!!!!!!!!!!!!!!!!!!!!! No way would I past that deal up..............

nelrod

Big decision, as you know they don't even make the NV5600 anymore. My buddy is looking for a main-shaft that snapped in 2 for the NV he abused the other night. I don't know what I would do. I wish I could cryo my whole engine and drive-train. I have read just as you said, high hp could make 4th gear go out and grenade the whole G-unit. PM XLR8R he has a lot of experience with broken G-units.

Topper

I would go with the NV 5600 but before I put it in I would take it apart and send all the shafts and gears to Performance Cryogenics in N.C. and have all the parts treated. Worked for me.
Good luck,
Topper

Wild04.5

some points to remember:

NV56 is a hard shifter and a steel carcass
G56 is as hard shifting and a aluminum carcass

Talk to Andy....

do the NV5600...

let me know when were swapping the setup into your truck... ill find the time to help Bro.

CD in NM

Guys are doing great at sled pulls with both trannys, they have managed to grenade both as well. I think both would serve you well. About the differences regarding the case being steel or aluminum, well, there might be a point where a steel case would serve you better, but parts and availability on the NV could have issues there too.

I've hammered my G-56 pretty good, it still takes what I throw at it with the stock clutch holding up. Many have upgraded the clutch and are happy as pigs in mud - sledpulling seems to be the pin to the grenade to either tranny.

Since all you'd have in the G56 is a clutch, do the swap and get everything else you need done for the changeover. You can always find a NV if you don't like the G56 and swap it later. There have been several build a good G56 with cryo like those who have done the NV.

CD

Danderson

I've driven three NV 5600's and I'll take my G-56 anyday. If you offroad and get stuck,reverse is where it's supposed to be:next to second so you can rock it. Parts availability is super also. Only drawback I can see is when you chuck the dmf they're noisier.

Brian Lent

They will both break no doubt, but the NV is holding up better when you put power to it. Parts is not an issue at all. NV all the way.

Sniper05

My G56 rattles because of my Dual Disk, but it keeps on ticking i have thought about doing the swap myself but, the G56 shift 100x smoother than any NV5600 i have drove, i have seen the G56 pull the sled a bunch, just as long as its in low side!

Riflemanusmc

NV brother. With the HP your going to throw at it. After talking on the phone, you know the facts...

rockcrawler304

G56 here.

You can throw a lot of power to them and I am pretty sure you are not doing any sled pulling so you will be fine. Also parts availability would be a big issue in my book to look at.

Just remember that ANYTHING mechanical can fail at any time. Both NV and G units can and will fail at some point.

Brokenarrow

If you sled pull go with the NV5600!

Coolride

I still don't know what folks are talking about saying the nv5600 shifts hard, my wife even says it's easier to shift than anything she's driven also, or I must have a freak unit.

RamPB331

I've driven old Dodge 2 tons with 4 speeds and 2 speed rear axles, IHC Tandem with a 5spd and 4 aux box, several different heavy trucks and semis with Mack and Eaton RoadRangers, and an 05.5 with a G56. The only thing that shifts easier than a G56 is my new Challenger's Tremec TR6060 unit.

Do they speak from experience or assumptions? I don't know why the aluminum case would flex any more than a steel case, if it was properly designed for stiffness. The casings are castings, and especially if the casting has stiffeners cast into it, it should not flex all that much. It would break before it flexed to that degree, I would think.

rip 112

NV5600 is the way to go Chris. For your intentions it will be more reliable. I've had a few friends get rebuilt nv5600s with no major issues so I would think parts aren't THAT scarce if the need arises. The proof is that the nv5600 is known to hold up to more abuse than the g56, and the gearing is abit better in final drive.

But in all actuality, they are both very good trannies, especially when you compare them to the prior GM and Ford junk. I would go for what you can get ahold of the easiest.