Also a shudder many people say feels like a vibration.
If the boots are torn on the ball joints if they aren’t shot now they will be quickly since the elements can get in there and all the grease can get out. Then again, I’ve been running torn ones on mine for two years with no issues yet so ymmv. Besides they very likely won’t cause the vibration you are experiencing.I've done some reading about lock-up shudder and this doesn't seem like it, since it's coming on at around 25-30 miles around. I suppose I could try some of the shudder fix to see if that has any impact, but the solution to that problem either way is to eventually replace the converter.
I got the new tie-rods in and while the steering has a much better feel and I've addressed the looseness I was feeling there, it didn't have an impact on the worst of the vibration. I noticed while I was doing that, that the lower ball joint boots are torn. I don't think that necessarily means that they're shot, but probably wouldn't be the worst idea to replace those as well at this point.
Another symptom - I noticed that if I'm creeping forward at very low speed (like just barely moving my foot off the brake), there is a very noticeable low-frequency vibration. I roughly timed it and it seems to be about 4-5Hz, or 250-300rpm equivalent. It goes away immediately if I apply any amount of power, or even just take my foot completely off the brake. Seems to me like this also points to torque converter - this would be right when it starts "converting torque" and applying power to the transmission. At the rate I'm feeling it, I don't think anything in the driveline or chassis could be making this vibration.
Lockup is supposed to lock the converter to engage the gear like in a manual - if you are in gear, the rpm will not vary except directly with speed. It happens in 3rd and 4th gears after a couple seconds in each gear if it thinks conditions are good. It will also do it in 1st at full throttle near redline for a second and in 2nd at higher throttle applications at higher rpm. 3rd and 4th happen all the time as long as the trans fluid is up to temp. You’ll feel it suck the revs down and lock the engine to the transmission for the more direct connection a manual has, with the goal of improving fuel economy.Tried manually selecting gears and it definitely had an effect on when the shudder/vibration occurs, it's a bit all over the place though. Does it also make sense that it's a continuous thing? In the lockup shudder videos that I watch, people have a second of shudder as it engages, but mine just shudders all the time.
How does the lock up work? Is it supposed to lock up at a specific engine RPM, or a specific Transmission RPM?
Sounds like it it could be converter shudder if you don’t feel it lock up.Drove it around a bit more today to try and figure this out. I drove in D and shifted back and forth between 2 and D when I was feeling the vibration and it definitely seems to be coupled with vehicle speed, not engine speed. I also just left it in 1 and got up to about 40 mph, and still felt the vibration come on around 25-30 mph. It is definitely much worse when accelerating, but not completely gone when I'm off the power.
I'm not feeling any kind of converter lockup like you're describing, but that could be just because it's hard to tell with the vibration that's happening. In general I would say the engine never feels well connected to the transmission, I would describe it as kind of sloppy. Unfortunately this is pretty much the first automatic I've owned though so I don't have a ton of experience with them. Seems like there should be more of a direct feel between the engine and the tranny than what I'm experiencing, but maybe that's just because I'm used to manual.
If I'm feeling it at a certain speed no matter what gear I'm in then I guess it would have to be downstream of the torque converter, or, at worst, a combination of torque converter and something else.
Interesting. Didn’t the OP already do the flexplate (which was destroyed) and still has a vibration though? If the flex plate is brand new I doubt it’s that.This sounds so much like another person who was posting exactly the same symptoms and it turned out the flywheel bolts had steered. He had pictures of the damage and nobody could understand how it still drove. The owner said it was a little squishy feeling like not a good connection. However it drove ok just with a mystery vibration.