I'm not sure where the right place to post this would be, but here goes.
I bought this DW745 Type 2 saw off of Facebook Marketplace. I think it was abused. I replaced both of the elevating shafts (5140100-04 Diagram # 82 & 5140100-05 Diagram # 84). I also had to replace both of the bevel gears (5140061-65 Diagram # 56).
The aluminum housing seems to be okay and the lifting shafts move in and out without much resistance. I'm still getting this chunky movement when I raise and lower the blade.
I'm looking for advice before I go though the whole process of replacing the entire aluminum housing (Gear Case A25607 Diagram # 213) on the motor.
Well, the screws were definitely over torqued, but it didn't fix the issue. I tried multiple methods to get one of the screws out but had to use a grinder and a flathead screwdriver to get it out.
I think I may have an Idea what is causing the issue after looking at the gears after your advice.
Since the clanky movement really only happens in one direction when the saw is on its side I figured it had something to do with the direction of the pressure being applied by the screw mechanism.
When I put the table saw completely upside down and then tried to move the blade up and down it was very smooth.
This led me to think that there might be some movement in the gears based on the pressure that's being applied. Watch this video to see what I'm talking about and you'll see a gap that closes when I go in one direction and opens back up in the other.
You can see the movement of the gear at about the 1:04 mark in the video.
That washer appears to be bent on purpose on the linked website for replacement parts and I'm guessing that it would keep the tension on the threaded dowel consistent. I think mine is missing or it was flattened out when someone torqued the mechanism.
Upon further research that is a bowed washer, spring washer, curved washer or wave washer. Their purpose is to retain tension and it's likely the solution to my gears binding. More can be explained in this video: https://youtu.be/sG1gSQGZQl8?si=nQhzR2a8TZUwJ5rY
I'm not entirely sure here, I have a new DW7485 so i'm not sure if the mechanisms are entirely identical. It does seem that the jack screw is translating along its length and it shouldn't. Not entirely sure why it is free to move like that, a missing or damaged spring washer might, like having looked at your video it does appear like there should be more things taking up space in that area.
I checked all of my local hardware stores. I think Lowes usually has these, but they said their small parts vendor hasn't come to restock anything in a long time and they weren't sure when they would be coming back. All other hardware stores in my area didn't have them or staff wasn't very helpful.
I will keep everyone updated. I hope this is the last part that I need to order online. I'll try to do a summary video when I'm done because I haven't found many that really get into this level of detail on repairing this specific issue online. I'm just glad I'm keeping this thing out of the dump and I hope to start using it soon so I can start to build and repair some stuff around the house. Super excited about building a French Cleat system in my shed.
Got the part in but my wife went into labor. We had a 8 lb 7 oz baby!
Obviously this is going to delay the progress of this saw project.
I did want to mention that the bent washer isn't very "bent". I'm going to figure out how to provide measurements once I can get to focus on this again.