Been following this thread for a while, some good information!
A few years back I was hunting for the Chevy version of the 833 but didn't have any luck finding one. I do have some experience with the Mopar version however and am currently running one in my 57 Plymouth behind a 354 Hemi with 4.10 gears.....vehicle weight is probably around 35-3600 pounds.
In the mid-late 70s both Chrysler and Ford both played with 3+OD transmissions in the quest for better fuel mileage and converting existing 4 speed tooling to do this was the quickest way to get there. The biggest complaint was/is generally the less than optimum gear splits for any type of spirited driving.
Back in the days of the national 55 MPH speed limit these transmissions were generally put in front of rear ends with relatively high gearing (3.00 to 3.50 range) and fairly low output engines. In the case of the Mopar A833 OD the transmission uses relatively deep 1st gear (3.09 if memory serves correctly). It's great for getting a heavy car without a lot of bottom end torque moving under normal conditions but with 4.10 gears it winds up being almost too quick to be useful for really launching the car (I've hit the rev limiter more than once in low gear). The 1-2 gear split isn't too bad but the 2-3 split is pretty wide. A lot of people who drive with these transmissions really wish they had 1 more gear on a lot of occasions. All that being said they are still fun to drive and do make a decent reliable transmission.
In my experience there are 2 or 3 weak points on the 833 ODs. The first and most major one is the aluminum case. They crack especially when used behind anything with significant torque and aggressive shifting. Although they are a little harder to find, I would defiantly hold out for a cast iron case version (which I have in the 57) or keep in mind that the aluminum case is not indestructible if running one of those.
Although I've never run in to it, on the aluminum case 833 ODs the counter shaft is a floating design. Some people have reported wear in the case because of this resulting in oil leakage. It can be repaired by boring and bushing the case, but is another reason I tend to shy away from the aluminum version of this transmission.
On a normal non OD A833 4 speed the input and main shaft are locked together in 4th gear. On the OD version of the main shaft is spinning faster than the input shaft in OD and over time can result in significant wear on the bearing end of the main shaft where it fits into the rollers on the input shaft. Pretty much something to look for when you tear one down.
Back in the late 60s when I was working in a Chrysler Plymouth dealership there was a service bulletin regarding the use of ATF in the A833s. If the transmission shifted hard (and especially in cold weather) it was recommended that a pint to a pint and 1/2 of the 80-90 weight be pulled out and replaced with ATF to thin the lube. It worked well on hard shifting transmissions, but from personal experience if you have worn synchronizers (grinding when up or down shifting) it will only aggravate the situation.
