Two odd symptoms just started

I have been a member for a while and have been reading even longer. I have not felt that I have had anything to contribute yet, just been trying to learn.
My first Toyota after a life of Fords.
06 Tacoma, 2.7L, 4-speed auto, 2WD, X-cab, bone stock.
I bought used Jan of 20 with 111k miles on it.150k miles now.
I have just done general preventative maintenance, no break-downs or issues yet. Fluid changes, filters, spark plugs, front brakes, etc.
I don't drive it very often, my daughter usually does. I drove it the other day and noticed two things that seem to have started together.
When taking off from a stop, or slowing to a stop; say from 0-5 MPH and 5-0 MPH, it feels like you are driving on a wash-board.
The second thing is when cruising and highway speed, it sounds a little like a jet engine; sort of a higher pitch whine.
Has anyone experienced these? Something I should be looking for?
Thanks in advance.

 

Check the u-joints for binding. That would give you the slow speed washboard feel.

 

Does the whine follow RPMs? It could be a ground loop.

 

I’ll guess center bearing.

 

My guess as well. Carrier bearing going out / gone

 

X3

 

Thanks for the replies everyone. I did not think of that. I was fearing a torque converter issue. I did not want to share what I was thinking at first though, I wanted to hear what everyone else had in mind.

 

While you’re there… maybe seriously think about having a whole new driveshaft made. Fleet Pride makes great affordable prop shafts. Buy once..

 

The more I think about this, it certainly makes sense. One other symptom that I basically dismissed and forgot about: it would make a swoosh, swoosh, swoosh sound as it was backing up in the driveway.
Is there a place to find the procedure, torque specs, etc. to do this replacement?

 

Echoing that this sounds typical of driveshaft u joints and/or carrier bearing. There's a bunch of threads and videos with DIYing both repairs

 

This morning, I crawled underneath my truck. All the U-joints seem very solid, I could not budge any of them at all. As for the carrier bearing when I pushed and pulled on it, it would move a little, but did not seem excessive to me. When I really reefed on it, I could get a faint bang noise out of it.
I swung by a local, independent repair shop. I have gotten to know the owner pretty well over the last few years. He has been good to me too, so I wanted to get a price from him to see what he would charge me to install a new bearing. He had his best driveline guy check it out. He put it up on the lift and pushed and pulled and looked around. He took it for a drive then. He is leaning more towards an issue in the rear diff. He says that because he does not see or feel anything wrong with the carrier bearing. He also says that when on a smooth road and you let off when doing 55, the way it whines to him sounds like a rear diff. He recommended I drive it for a while yet and let it get worse, so that we can tell for sure where the issue is.
Thoughts on all that? Are rear diff failures a thing on these trucks?
I of course don't know anything about the first 14 years and 111k miles of this trucks life. There has not been any towing or hauling the last 5 years, 40k miles.
May of 23, at 135k miles, I changed the rear diff oil. I put regular Valvoline 80W90 back in, nearly a full gallon. The fluid that came out looked fine to me.
I appreciate everyone's input on this.

 

The way to check for binding u joints is to unbolt the driveshaft and then articulate the joint by hand. A bind will give you a low speed wobble feeling. I haven’t read about many differential failures on here over the years. Good luck.

 

No, not really.

Echo the above about checking u-joints. Are they greaseable or sealed? Sometimes adding a pump of grease will temporarily help if greaseable.

You added a gallon of gear oil? I think it only calls for 3.1 qts. Not sure overfilling would cause any issues, but you might park on a level surface and pull the fill plug. Check A) level and B) any unusual looks to the oil if you can peep in or take a pic through the fill hole.

 

I did lay under there again and poke around. I did not see anything out of the ordinary at all.
I did notice one thing, which I had honestly forgotten about. A while ago I had to replace one tire. I debated back and forth about replacing all four, but I waited a little while as the others were okay yet. After some time, I went ahead and replaced the other three tires. Two different sizes make their way to the rear axle. For about 6k miles now, I have a tire on one side with 6/32" of tread and one on the other side with 9/32" of tread.
Surely that is not enough of a difference to cause any damage in that amount of time, is it?
Again, it is a base model with open rear diff. Zero towing or hauling.
I do not see any grease fittings; on the slip-yoke or the U-joints. The diff and axle seals are all dry.
My owner's manual says 3.1 Qt for rear diff. I probably, if I recall correctly, put in between 3.5 and 3.75 Qt.
What I thought about doing is changing the rear diff oil again and taking a sample and sending it in for analysis. That should say definitively if there is a diff issue, correct? Blackstone would be as good a place as any to send it to?