Information on the G56 is just a Google search away, so I won't clutter this thread with such available information. What is important here is that there are some very easy to correct differences between the 2wd and 4wd transmissions. The most important is the output shaft seal. The 2wd seal seals against the output yoke, and the 4wd seal seals against the output shaft itself. If your donor is a 2wd, you will need to change this out because without an output yoke, the seal has nothing to seal against. I would recommend replacing both input and output seals anyway... the trans is out of the truck, what better time to do it?
The other difference is on '05 and '06 2wd transmissions, the rear mainshaft bearing snap ring is omitted because, according to TSB 21-006-06
, "the output yoke retains the bearing." If your donor is an '05 or '06 and a 2wd transmission, make sure you have a snap ring here. If you don't, get one. All 4wd transmissions have this snap ring, and my '08 2wd transmission already has this snap ring, so I'm going to assume that they made them standard somewhere along the line. Honestly, I'm not sure why the bearing needs a snap ring. It's pressed into place against a step on the mainshaft, and the cup pressed into the case retains it from moving the other direction.
But the Mercedes goons say we need one, so I guess we need one.
My donor trans was pulled from a supposedly rolled '08. The guy I got it from said over the phone it was in good shape. Turns out he lied. Now, he may have been mistaken but he also conveniently omitted the part where the factory flywheel exploded and sent chunks through the bellhousing. And the part where one hole was patched with JB Weld. He let me discover this for myself after I'd spent an entire day driving 300 miles to check this thing out. I also noticed a very slight "sticky" spot at each revolution of the input shaft. That one could have been easily missed, but there's no way he didn't know about the bellhousing damage. At any rate, the trans turned over in every gear and the price was right, so I brought it home.
Here is is. Bell housing damage is visible in this picture, there's a hole about the size of a nickel in the middle of the bell housing right behind a gusset about halfway up. There was another hole about the same size, down low on the passenger side. This one was filled with JB Weld (which made weld prep REALLY fun). Then there were two places where something hit hard enough to crack it all the way through, but the chunk did not penetrate. Quite a few of the internal gussets were also cracked or chipped.
The gaping maw of the bell housing. One hole is now easily seen, the part on the left where light is shining though. The blob of white at lower left is the JB Weld
After the line of bull this guy fed me, there was no way in hell I wasn't going to thoroughly check this thing out before installing it. Disassembly was a breeze once I got a T60 socket to remove the 5-6 shift fork pins. The transmission has a very straight forward design, almost elegant in it's simplicity.
Here is is, 'sploded. Once again you can see one of the holes. Countershaft is standing up, mainshaft is on the towels.
The sticky spot on the input shaft turned out to be 6th gear missing a few teeth. Good thing I found it because it would have let go entirely the first time I got on it hard in 6th.
Once I had the case apart, the bellhousing damage was easily welded up. I am no stranger to welding cast aluminum, and like always I chose to TIG it. In repairing this damage, I found that the case casting seems to be of very high quality. Porosity was very minimal and the alloy used responded surprisingly well to the welding. Keeping the heat down in the whole casting was the only challenge, but all that took was time. Pictures:
Upper crack & hole, outside.
Lower crack & hole, outside.
Lower crack, hole, and repaired gussets, inside.
Detail of lower, crack & hole, inside.
Upper crack & hole, inside.
I will also if course be changing the output seal to the 4wd one and will also change the input seal, just because. I will weld a fitting for my transmission temperature gauge onto one of the PTO covers. Everything else looks really good in there, and aside from a through cleaning, the only other "modification" I plan on is reinforcing the welds on the reverse shift fork. They have been known to fail, and after inspecting the welding job they did, I'm not all that surprised. Stress risers everywhere.
I can correct that tomorrow.
With the factory 47RH/NV4500 adapter, a standard G56 clutch will work with no problems. You will most likely want to do a single-mass flywheel conversion, and I recommend contacting your favorite clutch vendor (Peter at South Bend helped me out a lot). Let them know what you're doing, and what you need from the clutch, and they should get you squared away. There have been reported fitment issues between the starter and ring gear with a certain other adapter, I will have to look that up and edit the information back in later.
Transfer Case Input:
If you're coming from an auto, you need to swap out your transfer case input shaft or get a transfer case that came from behind a manual. The good news is all the Dodge manuals use the same spline count: 29. The bad is that if you are switching the input, there are still 2 shafts to choose from. One uses a wide bearing, the other uses a narrow bearing. The good news is Quad 4x4 has very detailed tech notes on which one you need. Get the assembly number off your case tag and compare it against the tech notes for the two (QU10889 and QU10699) shafts to figure out which one you need. I also picked up a complete seal/gasket kit for my NP241 as you have to take the case pretty far apart to swap inputs, and mine was seeping anyways. I'll also inspect/replace any parts I find that need it. I'm not expecting much in the way of that, but you never know.
As far as transmission and transfer case parts, I had excellent service from Andy at Standard Transmission in Ft. Worth, TX. He spent a total of probably 45 minutes on the phone with me and was super patient and helpful while we made sure I was getting the right parts.
As far as pics, my phone camera recently got smashed so they'll either be crap photos, or I'll have to find a different camera. I'll get some pics tomorrow.