Diagnosing a grinding sound/feeling

I have a weird issue that I'm hoping one of you can solve easily. I have a 2013 TRD Sport V6 Access Cab. It has 177k miles and I've owned it for only the last 2k miles. It's my first truck. It has been great to me since day 1, apart from this one issue.

When I get up to and between 28-43mph, there is an intermittent grinding sound and feeling in the pedals and steering wheel. If it gets slower or faster as I decrease or increase speed, it's hard to notice. It's still there at higher/lower speeds but this range is when it's felt the most. It's not a violent grinding but it's enough to notice. It's been doing this since I got it and now that it's been getting warmer, I have begun troubleshooting. This is what I've done/discovered so far.

• It doesn't matter if its in gear or if I put it in neutral in that speed zone. The sound/feeling still happens.
• Oil/filter change done. I didn't expect this to fix it, but it was due.
• Replaced both front bearings, rotors, and brake pads. This repair went super smooth and everything came off/went on easy.
• Flushed/replaced power steering fluid. I didn't expect this to fix it either, but it was low and looked dirty.
• It doesn't matter if the truck is cold/warm, though it feels more "grindy" when cold.

Now this is the weird part, and hopefully the part that makes one of you go, "Oh well its obviously...". This morning, out of curiosity, while I was going about 35mph, hearing/feeling the grinding, I put it into 4WD (4H). The grinding sound and feeling was suddenly GONE. After about a minute, I put it back into 2WD and the grinding came back.

What do you think? Front diff issue? Replace the diff fluid? Something else entirely? Thanks for reading/helping.

 

Search ECGS bushing. It sounds like the driver side bearing in your front diff, that the axle shaft rides in. If you've done all the repairs you've listed thus far, it sounds like it's in the scope of your abilities. There are several good write ups on here and a few YouTube videos as well.
Jump in the rabbit hole!!!

 

Interesting! I had not heard of this. Why only driver side? Does this needle bearing that needs to be replaced also exist on the passenger side?

 

You can check your axle for play at front diff driver ..

 

Of your lifted above 2.5" it's recomended

 

Throw out bearing if it's stick remote ....possibility

 

The passenger side isn't normally the problem, just the driver side. The real tell is that the problem goes away when shifting into 4WD. Yours sounds 'text book'.
I did mine a few years ago and it's been good ever since.

 

Great! Thank you! I watched some videos last night and will order the parts to bang this out. When doing a repair like this, are there any other parts I should replace for convenience since I’m already in there?

 

...pay attention when setting the seal flush, as leaks from there was what I had to go back and deal with, and what seems to be the more common deal when putting it back together. ...photos illustrating t he seal placement can be a little hard to read, but if I remember, it is the outward most portion of the seal which contacts the axle should be flush with the stance of the outer surrounding diff surface. ...double check that, as that is based on memory from a few years ago,....

 

Yeah, from what I understand as well, you don't want to 'drive the seal home' and seat it all the way. Pay attention to how deep your current seal is before removal.
I didn't replace the seal when I did mine, just crossed my fingers. I figured if it leaked, I'd pull it again.
Also, you don't have to remove the spindle/axle nut at the hub. Once you get your truck up on some good jack stands, support the end of the LCA with a floor jack and remove the bottom two ball joint bolts. You can pull the axle shaft from the diff while it's still connected at the hub.
Have a few bungie cords laying near by to support it and pull the hub assembly forward, out of your way.
AND, don't forget to put some lube in the bushing before reinstalling your axles shaft!

 

Good to know! I went ahead and bought the new seal and seal install tool. $172 for everything so not too bad. I have some friends with Toyotas so maybe they can use these single-use tools in the future.

Love that I don't need to take off the axle nut. It gave me some trouble during the bearing replacement so I was worried about removing/reinstalling.

 

I did the ECGS bushing swap today in my garage. Took about 3 hours total, taking my time.

No more grinding. It's wonderful.

 

Happy for you! My parts are in the mail so I hope to be like you soon.