Make sure you are sitting on a sturdy object when you do ! Also, be aware the 5600 is no longer supported by the factory... they stopped producing these like 5 years ago. Most parts come from overseas and any reliable rebuilder will tell you this, and the fact that the quality of such parts leaves much to be desired. I picked up my 5600 in OKC yesterday afternoon after having them go through it because of numerous issues I've been having with it. They still drew a couple of question marks as to why it was doing what it was. Find out Monday when it goes in if they were right ot not. They showed me one gear that got past them the first time through that was machined totally wrong ( believe it was 6th gear). I do have a spare unit in the garage, if interested, thought I lost 3rd and 4th in, but once pulled, it seemed to be there,... go figure !

 

I've had both transmissions and would never have another NV5600. The G56 shifts SO much nicer. But my only power mod is a Smarty (right now it's on #7), and I don't drive it that hard anyway. For towing I back down to #5.

If I were to go to an auto, I would get one of the 68RFEs... I had the 48RE too and hated it even more than the NV5600.

Rob

 

a good friend of mine just blew his g56 in his 07.5. he swapped it for the nv5600. and he said he bought the tranny from the company that bought all the prints drom NV before the went out of buisness. i love my g56...and i haven't had any problems w/ it. but i've got amsoil and an extra quart in mine..so she shifts well for me, and even has 100k miles on it. i only hate the 6th gear ratio.

 

Have you found that the extra quart has made a difference in your shifting?
Or anyone else, for that matter?

 

Hey guys,
I have rebuilt 5600s a few times and I can tell ya there a very strong trans but can be broke. I have ripped the teeth off of a few gears and twisted a shaft in 1 myself. I have found the best cure was to send the parts to Performance Cryogenics and haven't had any trouble since.
I will tell ya one thing after slow rowing the 5600 for couple hundred thousand miles doubt I will ever have a truck without a built auto again.
Take care,
Topper

 

No good reason not to use an extra quart or two.

ATF doesn't climb very well and the high-pressure contact patch of gear mesh is higher than the factory fill - besides, the aluminum case transfers heat pretty well, so more fluid splashing about can only help reduce operating temps.

 

Where'd he get that tranny? Are they reproducing them or anything?

 

it seemed to have made it shift a little more smoothly, not as notchy. i'm glad i did it.

 

he bought it from blumenthal....but here is the link to his swap.

http://www.cumminsforum.com/forum/6-...ht-5600-a.html

 

Interesting. Heck i wish i had enough power to break my G so i can get a NV5600! When tax time rolls around i just may think on this!