It’s a ‘95 Sahara 4.0 automatic that shifts hard into reverse and 1st gear. 1st to 2nd and 2nd to 3rd work fine. I first noticed the issue after doing a bunch of work on the drivetrain. I re-geared from 307 to 410, replaced the transfer case drop with an SYE, new rear driveshaft, new u-joints and a Detroit locker. I also changed the transmission fluid, filter and adjusted the bands. I adjusted the TV cable but had to do it manually. Mine didn’t do the “push the button, pull the black piece out, push the accelerator and bang, it adjusts automatically”. I just took all the slack out of the cable. Once in a blue moon it will shift into Reverse and 1st gear smoothly which gives me hope it can be fixed. If there is anything else I can do or anything I need to redo please let me know. Thanks.
Since you mentioned manually adjusting the TV cable, make sure it’s set correctly. A mis-adjusted TV cable can create harsh shifts. If it’s too tight, it may be causing the hard shifts into reverse and 1st gear.
I'd also double-check your transmission fluid level. If it’s too low or too high, it can affect shifting. Make sure you’re checking it while the engine is running at operating temperature for an accurate reading. Seems obvious, but you know how Occam's Razor works!
A sticking valve in the valve body could also be causing the hard shifts. If you’re comfortable, you might want to drop the valve body and inspect it for any debris or damage.
A worn or damaged transmission mount can cause a harsh engagement into gears, especially under load. It might be worth checking to see if that’s the case.
You also mentioned adjusting the bands, but make sure to follow the specific procedures for your transmission. Double-check that they are set to the correct specifications.
Just trying to cover the most obvious stuff that comes to mind first. I usually find that in situations like this it ends up being the most obvious answer (Occam's Razor, again!).
Since you see a smooth shift every so often, it might indicate that the components aren’t fully failed but could benefit from some adjustments. Good luck, and keep us posted on your progress!