Engine/Transmission (1994 - 1998) 12v 2nd Gen G56?

[torqmonster]

Has anyone put a G56 in a 12v? If so what's the info? Has the G56 been proven or should one stick with the NV4500?

 

[WPeschel]

Has anyone put a G56 in a 12v? If so what's the info? Has the G56 been proven or should one stick with the NV4500?

If you want a six speed you have two choices... The NV 5600, or the g56... The nv5600 is no longer in production so parts are getting harder and harder to find... I like the way the g56 shifts IMO better than the nv5600. . I'm not sure if anyone has put a g56 in a 12 valve yet???

 

[wcjp]

I've seen it done here on the TDR. The first one I recall being done required a small body lift. Later, another member found he was able to modify the cross member. It required some cutting and welding. It looked like art when completed. No body lift required. These conversions were on trucks already equipped with a manual transmission. I think SouthBend Clutch had the required hydraulics.

 

[RSivula]

was it this topic?
https://www.turbodieselregister.com...98/177739-nv-4500-g56-6-speed-conversion.html

 

[CTD12V]

Here's the one about notching the crossmember:

https://www.turbodieselregister.com/forums/24-valve-engine-transmission-1998-5-2002/184539-g56-conversion-compleate.html



CTD12V

 

[WilliamJones]

Unless you just want a 6 speed I would go with the NV4500. It has the same final drive gear ratio as the 6 speed. The six speed just has another gear between 3rd and 4th. And the NV4500 is much more readily available, and more reasonably priced. If you go with the NV4500 take a look at a new main shaft with clips to hold the 5th gear from backing off.

 

[Forrest Nearing]

I'd stick w/ the 5sp. Holds plenty of power, cheap/available/etc. And you have one less shift to make. With a GSK and some power, the 12v will cover the 3-4 spread just fine.

 

[Vaughn MacKenzie]

I'd stick w/ the 5sp. Holds plenty of power, cheap/available/etc. And you have one less shift to make. With a GSK and some power, the 12v will cover the 3-4 spread just fine.

Let me beg to differ a bit. On the route I drive with my '96 going to work I find myself constantly shifting back and forth between 3rd and 4th due to varying traffic speeds. . . speeds that don't vary much. With a 6-speed 4th gear is just right for the traffic, no need to be shifting back and forth. I would love to pitch the 4500 in my '96 for a good 6-speed. After owning 2 6-speeds that's what I'd rather have even driving in town. Power can cover the gaps to a degree but it doesn't do much for fuel economy having to rev it or lug it to compensate. With the ease of rowing the G56 a few extra gear changes speeding up and slowing down wouldn't bother me.

 

[Woodenhead]

Vaughn's right. I don't think I'd ever want another 5 speed (although I still have the old one ). It's nice pulling a hill on the interstate with a load and being able to dump it in 5th gear and still hold a good speed without having to rev the motor to uncomfortable RPMs.



Yes 1st and 5th are the same as 1st and 6th but it's not just another gear between 3rd and 4th, all of the ratios are closer which makes it nice for getting a load rolling. With the 5 speed there were many times when it seemed like I just didn't have the right gear, now it's like I always have the right one.



Obviously my experience is with a 5600. I haven't compared ratios on a G56, maybe I should do that before I run my mouth too much .





Mike

 

[AKaiser]

Prior to 2007, the OD ratio on the G56 is a . 79. Since then, . 742. Unloaded, it can be shifted as a 5 speed (true 4 + OD). If you wind it up, you can skip shift (run it unloaded as a 3 speed (2-4-6)) but I think running it 2-3-4-5-6 in rapid sucession keeping it in the low end of the torque band and out of the fuel is better for MPGs.