Trust me, you don't want to even accidentally see one. Seriously. If you value your sanity, forget you asked!! I first saw one about 2 weeks ago. It was on my alignment machine and I HAD to see the engine compartment. I wish I hadn't seen it. I have had GRUESOME nightmares ever since.
It sits pretty far back. Sadly the turbos are at the back of the motor (you can see them though). As far as work on them goes, I highly doubt you would even want to attempt to work on them without removing the cab. But if you have the patience and small hands I guess you could.
Well, I've got news about the turbo work/cab off deal. I took my truck in Tuesday a week ago to have an oil pressure sensor replaced (was getting a CEL). The service writer said they would have to remove both turbos to get to the sensor. I said woah! That's a cab off job isn't it? He said no, he didn't think so but he'd check with the diesel tech. Diesel tech said no also. Anyway, brought the truck in at 8am, sat in the waiting room until 930am and the service writer came in and apologized. He said they had the wrong part and the tech was putting my truck back together (putting the turbos back on). So I had to wait until this past Tuesday and they did get the right part and everything went well. Total time was about 2 hours. Now, I said all that to say this. I called another diesel tech at another dealer and asked him about having to remove the cab to work on the turbos and he said... at first it was a cab off repair but someone came up with some type of tool to get the turbos off without removing the cab. The reason for this was that lots of construction guys were welding on ladder racks and things like that and they would have to cut off the racks before they could remove the cab. I don't know if he was just blowing somke or not, but thought I'd pass on what I was told.
To remove the turbo charger with the cab on you have to use a lifting bracket which is designed to not damage the seal between the high and low pressure side. The turbo charger when lifted has to be kept level as not to damage the oil drain tube.
one good thing about our 6.4L engines...if you drop a tool while working on them it wont make it to the ground....theres little to no room to see daylight much less have an adjustable wrend fall on the ground via the engine compartment.