No reverse other gears slipping

You could try draining and refilling the transmission properly (never use a high-pressure drain) and replacing the filter and transmission fluid with the proper type (it’s in the owner’s manual). And, it may work for a time, emphasizing MAY WORK, because I think there’s a lot more going on than just the fluid.

You told me you were driving along; hit the brakes, while reversing. Well, I have to tell you that this isn’t very good for any extended life for your transmission. Indeed, it’s probably the worst thing you can do.

Here’s an example of what has happened. Imagine you are running along in, say a marathon or half-marathon. As you are running, someone falls in front of you so you have to stop short and you have to jump backward. Did you feel the pop in your knees? If so, you may find that you have suddenly become a casualty as well because you have just torn the ACL or MCL. Effectively, you have done the same thing to your tranny.

At best, you may have just hyper-extended the bands/clutches and gears or you may have popped the torque converter. However you choose to put it, I think there has been a bunch of internal damage which has turned your transmission into “junk,” to quote your question.

If you want to hold onto the pickup, my advice is swapping out the transmission and putting in a rebuilt for starters, which should cost about $3,400.

Here’s where it gets a bit dicey, though. Because of the way things happened, you may have damaged the input and output shafts and you may also have damaged the differential, as well. If that’s the case, then you are looking at another $2,800 in repair expenses which will push things over the $6,000 mark.

Let me know what happens, I would like to know.