Is there a good Pic of this? I'm wondering what Access panels are for what? I want to create a Heavy ARV based on the M1 Chassis. Just wondering what's where in the Rear of the Hull??

Counterclockwise from forward left (approximate 11 o'clock position) (top deck only)
Bolted plate is the NBC overpressurization system.
Left side grills provide air intake for the engine.
Precleaner doors are for accessing the V-packs (air cleaners).
Left small grill doors provide access to the transmission oil dipstick.
Right rear access panels are for the engine oil dipstick.
Right side grill doors are for accessing fuel filters.
Right rear access panels that run along the edge of the hull are for the batteries.

The two little access panels that are along the very rear edge of later Abrams tanks (not on M1, M1IP or early M1A1) are to access the right and left side oil cooler fans.

I'm not an expert or anything, but I have pulled my fair share of M1 engines and checked oil, cleaned V-packs, etc.

Sounds like not much can be put back there then.........

So Rob, the 64 dollar question. Is it easier/quicker to pull the pack of an M-60a1 (Rise) or one of these M-1a1's?

A good crew and mechanics can get it out in under an hour.

Blaster,
I am not Rob but pulling the pack on a M-1Series is much easier that pulling the pack on a 60... Unhook the final drives through the sprocket, lift the deck, undo the wiring harnesses at the panel/ fuel lines and lift the pack... No "breaking" the final drive collars, wrestling with cannon plugs, fooling with the linkages...
John