[oil pan 4]

I may have located a source for GM 10.5'' full float 3.21 gears, at "thejeephut dot com".
(EDIT: the jeep hut does not have any 3.21 gears)
Says they are "discontinued" so I believe that means once they are gone, they are history, unless someone else does a production run.
Total for me looks like $307. I could easily save $300 in fuel swapping from the OE 4.10 gears to 3.42-3.21 in this pig.
The 3.21 gears and an ARB air locker and I will be all set.

Everywhere else I have looked might have the FF 10.5'' 14 bolt 3.21 gears listed but shows "not available" or has a price of "$0.00". Kind of makes sense that a jeep place would have them. I don't think GM full float 10.5 inch rears are popular with jeep guys. I think they like to stick with Dana or ford 9''.

The current half ton diesel setup is 31'' tires, 3.42 (10bolt) rear. The 3/4 ton suburban will have 32 inch tires and it looks like I will have the 3.21 gears now.
To counteract the taller gears and taller tires at low/start/stop speeds and keep from going from a tow monster to a towing turd I have a few alterations to make to the 6.5L/TH700R4 before it takes the place of the gasoline 7.4L/TH400.
1 More fuel. At the very least turn up my injector pump, maybe get one that can fire more fuel through the injectors.
2 Replace the torque converter, since the one on the TH700R4 is shot. The original OEMs diesel converter should be 900rpm stall. The one I found is 1200rpm built for diesels that go 4x4ing and/or tow.
3 Activate the VGT on the holset.
4 At higher speeds while towing revert the TH700R4 back to TH400 mode by putting it in 3rd gear.

In other news the rod and jet tuning kit came in, then a few hours later while I was at work another package with some additional smaller jets not included in that big kit arrived.