Unexplained Noise - Differential?

I have an undiagnosed noise coming from my Tacoma that I'm stumped on. The vehicle is a 2005 Tacoma TRD, 6-speed manual transmission, only 55K miles. Everything is stock on this TRD - no additional lift, etc. While out of state last December for the holidays, I had a brand new set of tires installed at a Massachusetts NTB. The tires are Michelin LTX M/S2 - a top rated tire. Immediately after driving away, I thought the new tires sounded much louder than my previous 8-year old worn-out AT tires. Unfortunately, I needed to depart the following day so I didn't have time to return for diagnosis. I also figured I should let them wear a little, in case that might help.

In early February, I returned to a local NTB who stated I should have performed an alignment. I authorized them to perform an alignment ($) but that didn't help; however, their technician also told me (after he finished his job) that I needed a new right-front wheel bearing.

Next, I brought the truck to a trusted mechanic. They normally work on SAABs (my other car is a 25-year old SAAB 900). They're not experts on trucks, but the mechanic previously owned a Tacoma and they've also been very honest in past repairs/maintenance. Anyway, they drove the truck, heard the noise and agreed it sounded and acted like a wheel bearing. They drove down a street, swerving from one side of the street to the next. When turning to the right (more pressure on outside/left tires / less pressure on inside/right tires) the noise was reduced. When driving straight or turning to the left (constant/increasing pressure to the right tires) the noise was present or increased.

Despite NTB's recommendation, the mechanic felt the noise was coming from the rear of the vehicle. They had a second mechanic ride in the truck bed, listening while they drove.

The mechanic replaced the right-rear wheel bearing, but no improvement in noise.

Next, they replaced the right front wheel bearing. Again, no improvement in noise.

In case the problems are wheel/tire related, they moved the tires around:

They cross-rotated the tires. Rears went moved straight ahead to the front, and fronts were moved to the rear but swapped L-R. No change in noise (still on right side)

Next, they swapped the fronts L-R. At this point the two tires which were originally on the right side, were now on the left. Again, no change in noise (still on right side)

The mechanic checked the gearbox and differential fluid levels - everything looks okay there. At this point, the mechanic believes it could be within the rear differential, but he's not sure and now recommends I take the truck to someone with more experience with trucks.

Any thoughts / recommendations on my problem.

Also, can someone recommend a trusted Toyota mechanic in the DC/Maryland/Northern Virginia area?

Thanks,

Kevin

 

What does the noise sound like? Is it a grinding noise, a chirping noise? Is is consistent at different speeds or change when you go faster or slower? Are there any times that you notice it any more than other times?

 

Thank you for your reply. It does not sound like a chirp, grinding, or clunking. It's a loud hum, sometimes resonant around 35mph. As I increase speed, it gets louder. I realize trucks aren't quiet, but it's much more difficult to listen to the stereo at highway speeds.

 

I'm having a similar problem which I have determined is coming from the front diff driver side output. A lot of play in the cv half shaft from the diff as well. I am also aware of a bad wheel bearing on the driver's side too. I'm going to replace the wheel bearings(both sides) this weekend before I jack with the differential. The thing has 140000 miles on it and it's been a great truck. Matter of fact I just came off a 3000 mile road trip from Washington state to North Carolina pulling a trailer and the bitch was still able to crank it up to 90 mph!

 

Sounds like it could be the drivers side front wheel bearing, I would jack the wheel up and check for a noise or play... that's low miles for a 05

 

if its the diff, you'll notice the noise get worse when you coast too - is that the case?

 

Have the driveshaft u-joints been greased lately?

 

Yes. Almost sounds and feels like you are running in a high rpm.

 

Thanks everyone for all the replies on this thread today:

Zopperman: The noise is just as loud when I clutch and put the vehicle in neutral and coast (my truck has the 6-speed manual gearbox).

Steves104x4: I'm unsure about the drive-shaft u-joints. I'm dropping the truck off for evaluation next week, and I'll ask them to inspect those.

toyotaman29: Last week, the vehicle received brand new wheel bearings w/ seals on both the right-front and right-rear wheels. No improvement.


In case it matters: six months ago, I had a low-speed fender bender (my fault) wherein I struck another car, while both of us were turning. I was in the inside lane and attempted to swing into the outer lane, and failed to see someone in my blind spot. My right-front (including my tire) struck the other vehicle, causing right/front bumper and fender damage. We were both traveling the same direction, so our relative speeds were pretty close. The accident resulted in about $3K of body work to my truck. I imagine the right-front wheel had some sideways-applied forces, but everything drive-train related seemed okay so only body-work was needed: bumper & fender repairs.

I raised this issue with my insurance company again recently, before my mechanic attempted the wheel bearing repairs. They sent out an adjuster; however, the mechanic told him that he thought the noise was coming from the rear, so the adjuster concluded it was unrelated to my accident. Ultimately, if this problem is from the rear of the vehicle, that makes sense. I'll be dropping the truck off next week. If, following their initial evaluation, they want to fix anything in the right-front, I will speak with the insurance company again before they begin repairs. Again, this truck has only 55K miles.

 

I'd check the left side bearings, especially the front one.

I had the opposite happen when I put new tires on the truck last summer, going from more of a road tire to an AT. Before getting the new ones put on, I always thought the old ones were pretty noisy for a road tire. After getting the new ones, I had the same exact noise that I previously thought was the old tires, along with a new road hum noise from the ATs.

After digging into it more, I determined that one of my front wheel bearings was going out (right side), so I ordered the hub assemblies from BamaToy on this site and replaced both of them. That fixed the noise, and now all that's left is the tire hum from the new AT tires.

Maybe the ATs you were running were noisy enough to conceal the other sound a bit, and now that you've got a less aggressive tire on there you can hear the noise more?

In my case, the noise from the wheel bearing would start around 25-30mph and increase in frequency the faster I went. I could also feel a slight high frequency vibration in the floor and the steering wheel. The best comparison I can make is that it sounded like riding in a turboprop airplane (like a Dash 8) at highway speed. I could also reduce the noise by swerving as you stated your mechanics did.

 

x2

This hit me when I had the growl on my first car. I went through an S-curve every day to school, and in the first turn (right) it would get loud, and the second turn (left) it would go away completely.

I couldn't feel any play in the bearings, but the front left side was gritty so I changed it. Seemed logical with its behavior. Unfortunately the noise didn't change at all - the front right side was the culprit so I had to change that one too. Sometimes it just doesn't fit the profile. Fortunately Honda bearings were relatively inexpensive at the time.

 

If it goes away when you put it in 4x4, it is the left front diff needle bearing.

 

Partially true, I replaced my left needle bearing earlier this month and it tightened up the CV axle there. I now notice that my right needle bearing, while the axle is tight, now hums sometimes, definitely not like the all the time hum with the left side.

OP, while you are driving switch into 4H. If it goes away, you know it's the front diff and not the rear. At least that will narrow it down for you.

 

If it's not the wheel bearings and they think it's coming from the rear diff, they could put it up on the lift with a guy inside the truck. Once it's up in the air, the guy in the truck should start it and put it in drive. Then someone else can go underneath and listen with a screwdriver to see if anything is going on with the diff.

The only that comes to mind in this case is that there won't be a "load" on the rear wheels since they'll just be hanging, so I'm not sure if this would have an effect on anything or not.

My money would still be on the left side wheel bearings though. It sounds very similar to what I had going on.

 

I think its your tires bro I just had the same tires put on saturday. ltx ms2 P265/70/16 and they are loud yet they are supposed to be the quietest most comfortable highway tires made for trucks. my cupped dunflops 10ply a/t tires are quieter than these. I think im taking them back and getting my 800 dollars back

 

I had those same MS2's on my truck and they were very quiet and rode great, I now have the AT2's which are also very quiet with no road noise.... not saying it couldn't be the tires but i've never had any problems with Michelin tires.

 

Don't get me wrong they ride great but I was not expecting them to howl down the highway so much I had to turn the radio up. The whole purpose in buying those tires was to make my truck quiet and smooth on the highway which is where I do 99% of my driving. tire rack ranks them quietest truck tire. maybe my tires and his were made differently than yours. My gf even complained when she got home today from her commute and it was her first time driving it since I put the tires on.

 

It may be something in the newer MS2's tires, the old ones i had were made in like 2010 or they could have changed the tread pattern a little...not sure, maybe they will get quieter in few weeks after running them some.

 

I'll give NTB a call in a few minutes and try to arrange them to test my vehicle with another Tacoma's wheels. I need to haul some furniture this weekend, so I may not perform this until early next week, but I will definitely reply back with the results of NTB's test.

 

So I was wrong and Im a fool the noise that i thought was the tires was bad wheel bearings i replaced both this weekend along with ball joints since i had it apart and my truck is silent going down the highway now. my bad michelin!!! i will say these ms2's are super sticky on the road I can't even turn them over with my v6 but i could smoke the hell out of those dunlops anyday. I had a chance to take them offroad before i changed the bearings and they did not let me down Im rather impressed with them now.