833 OD sticking in 4th, chipped synchro

If the new struts are dimensionaly the same as the old, and you install them; I can almost guarantee you that you will end up having the same problem ....... down the road.
The struts are captured by the brass, and limited in travel by the distance between the bottoms of the slots. As the brass wears, they creep up the brake cones, and the inter-slot dimension grows. This allows more space for the struts to come out and eventually they are able to pop out the back.
New struts will not solve this. You have to reduce the inter-slot dimension, by one of the following three ways;
1) install new brass that sits higher up away from the clutch teeth, or
2) move the mainshaft forward, or
3) move the Input gear deeper into the case.
Since all A833s that I have worked on, have this design problem, I just move the input gears back in the first place.

I should mention that if your box runs too hot, the brass will expand and climb down the brake towards the clutch teeth, opening up the inter-slot dimension; leading to strut pop-out.
However, the over-heated brass turns color, and yours are still bright yellow, so this is not your problem.
But Since you have it apart, check the faces of the brass for signs of having run that deep and throw those away.
Another thing I do is attempt to stretch the brass,, looking for broken ones.