Hard thump type vibration - 2009 4dr 4wd

I am totally new so I hope this is close enough to being correct. I have a 2009 Tacoma with 218,000 miles. About 2 months ago it developed a hard vibration of which I have never felt even on other vehicles. It make a thumping feeling of about 4 times per second and at a speed within the 25 to 30 mph range and moderate acceleration. There is no sound and it feels as it's coming from underneath the truck. At the starting period of the vibration, it was far between and less forceful and each time it seems to become more forceful and with less time between periods of vibration. when it first started, my passenger never felt it nor noticed it in any way. There is no sound. Now she immediately notices it and lets me know, "There it is!". I know it's going to appear at near 25 mph so I am prepared for it and if it does appear I immediately lift my foot from the accelerator so it will stop. I can them reapply gas without the vibration restarting. Any suggestion will be appreciated no matter how little or minute it may seem. I am at a loss but still searching. I have been advised of torgue converter shudder which that is one of my next attempts to go after. I am also replacing my hanger bearing just as maybe that's it. Previously this truck has been absolutely great. I've replaced the front wheel hubs and bearings, two sets of brakes, no rotors, 4 sets of tires, repainted the hood and roof and probably 20,000 miles ago the carrier bearing and all associated U joints due to my service department not using grease. Believe it or not, that's with 218,000 miles and plan to keep it a lots longer. Everyone around here is stumped and has suggested out. Thanks for any suggestion and if I ever discover what it is I will let everyone know. My name is Larry

 

Welcome! Surprised no one has responded, sometimes messages don't get a lot of traction in the new members section. You may want to post over in the 2nd gen section. Good luck!

 

Welcome aboard!