This G56 is destroyed! 

You recommend 50 weight oil for the G56. I tried that up here in NH for a year (Delvac 50) and when the cold hits, the truck is virtually undrivable. Shifting is barely possible. Even double clutching you have to jam the shifter for every gear. Switched to Amsoil ATF and shifting is much better.

Are there any parts that should be upgraded in the g56 while its apart other than the case or the better input shaft? Im kinda in this boat something in mine let loose yesterday started as an issue with first being hard to shift into then something broke locking first out all together to now any motion in forward or reverse is binding internally. Idk what kind of price tag im looking at but im sure its not good.

A Modern,modified 6.7 cummins is putting out power today almost equivalent to a Cummins NTC-290 in 1980. Except that those engines were mated to a dual counter shaft 900 series road ranger which is 400% the gearbox that thing is. If its single counter shaft, its weak.

thats a real carnage !

How? I have an g56 and I’m not nice and it’s fine at 105k

At that point just buy another one

Will the stock bearings fit into the heavy duty case beings the case has been reinforced there?

For around 400 horsepower what would be the better and longer lasting transmission a heavy case G56 with the lower 6th gear or a Nv5600? Planning on a swap in an 2005 that came with the 48re. Also towing in 6th is not recommended for the nv5600. What about the G56? Or is the ZF6 truly a better transmission than both as many say, I seem to lean to the NV5600 as i have had a few thanks

thats a big piggy bank

You never figured your comment about which oil to use. Hard to find 50w. Can you please tell us what is easier to find and to use over atf please.

I'm in the middle of a rebuild and cannot for the life of me find 6th clutch gear. Don't need the whole package Mopar sells (wouldn't spend $2k on it if I did), and Mercedes and Dodge , no help, it's like a phantom part. I found a part in Russia, but $304! I just bought the 5th clutch gear for $125, so why is 6th over double that?

Do you recommend using one of those side cover plates with a higher fill hole for the tranny fluid so that it accepts about a quart more?

Everything looks so dry? Was it ran out of oil?

How does having a heavy duty case help be a oem?

Ouch.