There most certainly is! If you have a cast iron OD unit (not super common), then you don't have to worry about this modification, but aluminum units have a floating countershaft. Basically this means that the shaft that the countergear rides on isn't a press fit into the case; I think the factory spec is +/- 0.005" of play between the countershaft bore and the shaft itself. This isn't an issue for the engines that chrysler put the OD units behind, but once you start throwing some serious power through them, then what happens is the countershaft slowly begins to wallow out the countershaft bore in the case. It starts out fine until it gets so bad that the countershaft gears come out of alignment and grenade the whole transmission. To prevent this, you can machine out the bore in the transmission case and install a steel bushing that has a tighter fit around the countershaft, which will stop it from destroying itself. Hot rod magazine did a writeup on it, but you might have to do some extra research: A-833 Aluminum Case Buildup - Mopar Muscle Magazine
The second weakness in the OD A833 is the mainshaft. To fit the overdrive gear on the shaft, they had to make the shaft smaller (and the gear is a lot smaller too). This basically just dramatically reduces the amount of abuse that 4th gear can take. As far as I know, there isn't really a solution to this other than "don't floor it in 4th." IMO, if you really need that 0.73 overdrive ratio in your car to go fast, you either have the wrong setup, or you need to buy a stronger transmission altogether. Again, it all depends on what you plan on using the car for.
People have varying opinions on how much power is too much for the OD transmissions, but there's stories of people running them behind 440s at the strip and having no problem. Personally, mine is going behind a mild 360 and it's gonna be treated as a three-speed with overdrive. It's also going to be driven as a daily driver for 95% of its miles, so I don't really need a bulletproof transmission.