Ladythump

99 4Runner Limited 4x4 v6
185,000 miles

The other day, my Runner just started howling. It sounds like I'm going through a wind tunnel. It's not wind related in anyway, it def sounds like a howling and seems to be coming from the rear end.

It starts at about 20mph and stays the same pitch and sound no matter how fast or slow I'm going. It does stop with I am not moving.

I'm reading it could be the differential. Maybe it just needs fluid? Please let me know some things I can check before I bring it to the dealer. Thanks.

Tofer

check fluid level... but iam going to guess you have a broken ring tooth

98runner210

x2 on checking the fluid. Also keep in mind the dealer is the most expensive option. If you have the money then by all means go. If you are on a budget (the reason why most of us drive a 10yr old vehicle, that and we love em) I would find a reputable local mechanic. Ask co-workers or friends to reccomend one.

ESQ

Would keenly like to find a good toyota mechanic around the sea to sky area, too... They seem tough to find here.

MUNJUE

diffs usually wine for a we while before the sound gets real loud,
diff noise is usually not noticeable till around 40-50mph more noticeable on acceleration and on over-run than cruising along

wheel bearings make a howling noise
when you move your steering wheel to the right then to the left dose the noise change in volume one side being louder than the other? if so it would indicate a wheel bearing, the noiseyer side being the bad bearing


3 likley causes,

1 check your wheel bearings, when checking the rear bearings make sure you know how to tell the difference between the spider gear sound and wheel bearings noise,

2 check your tyres for scalloping which can produce a noise similar to a wheel bearing being shot

3 check your diff, it is easily done by jacking truck up, placing on axel stands, chocking the front wheels,
make sure its in 2wd, start motor and put into gear so the rear wheels spin they should spin together with a lsd diff,
use a long screw driver with a hard plastic handle,
place the screw diver tip against the front of the rear diff housing near where the drive shaft connect you are checking the pinion bearing,(not against moving parts for obvious reasons) listen for bearing noise by placing the handle of the screw diver against your ear, then move the screw diver toward the rear of the housing to check the carrier bearings repeat on the other side of the diff,

a worn bearing will have a very rough sound to it,
a clicking sound would indicate either a broken tooth on a gear or pinion
or 1 of the bearings have lost the hardening in one spot of the bearing surface,

while its still jacked up you can listen to the rear wheel bearings by placeing the screw diver against the backing plate or axles tube, and listen, compare the noise side to side, should be a smooth sound,

after doing that jack up the front and check the front wheel bearing,
place one hand at 12 oclock on the tyre, and the other at 6, push the 12 hand in and pull the 6 hand out change direction, repeat, you are checking for movment, there should be slim to none,
there should be very little to no movement,
then, place one hand on the lower ball joint and spin the tyre there should be no roughness felt or noise repeat on the other side

eddieleephd

Honestly if there is any felt movement in our wheel bearings then it is time to replace them. my rear one was going out for about a year and a half and I couldn't figure it out because there was a grinding humming that went away when I removed the wheel and there was no noticeable movement in the wheel bearing. that is until the roaring started then It was very apparent that it was moving. So if you can pin point a side that the noise is coming from I would suggest replacing the wheel bearing if it is on the end of the housing. if in the middle then see above for diagnosis!!!

MUNJUE

front ones are adjustable, as long as they are in good condition.
rear ones get vertical up and down movement, you can place a bar under the tyre while trucks jacked up, lift bar you will feel movement, experience will tell how bad they are,

Ladythump

Let me add that I got under the truck this evening about 20min after I drove for about 40min. there is no leaking in the diff case but it was very warm to the touch and I'm guessing if I touched it as soon as I stopped driving then it would have been too hot to touch. Is this normal???

How do I check the fluid level???

I have yet to find a good mechanic in Sea to Sky area. And I'm not too thrilled with the Vanc dealer either. I might try to find one in Bellingham as I travel down there a bit.

It's def howling at 20mph and higher. I will steer to the left and right tomorrow to see if the noise changes. I will also check my tires as I added a new/used tire to the rear about 2000 miles ago. I also just had an alignment at the same time. The howling just started though.

I'm not sure if I will be able to check the wheel bearings on my own, I might have to find a mechanic to do that. Thanks for the help guys and hopefully I can get it sorted out and fixed cheaply.

MUNJUE

to check the fluid level, park on a flat surface, on the rear of the axel is a 24mm hexagon plug, not the one at the bottom of the diff, but the one on the rear. undo and remove the plug the correct oil level is when the oil dribbles out, if not it should be no less than 5mm from the plug height,

Ladythump

Okay I'm going to check the fluid level and hope that's the only thing that is making the howling noise. I'm guessing it's going to be something more than that.
Thanks everyone.

Ladythump

The cap to check the fluid was all rusted and I couldn't budge it, even after spraying it with WD40. I made an appt with the Ford dealer on Monday am.

theAuthority

Don't use WD-40 that is the worst stuff ....

Buy a QT of auto trans fluid and mix it with Acetone.

It is the BEST stuff you could ever use .... Dab some on, let it soak overnight.

My sources .. :https://www.yotatech.com/forums/f123...arison-193496/

theAuthority

Also to fix your howling, have you checked to see if there is a Cat in your bumper?

I kid I kid good luck

eddieleephd

If you want a penetrant in a can use PB blaster, it is also originally designed for pneumatic tools as a lubricant so you still have lube after your done!!!

AND What Is With This FORD dealer Thing?????

and this is a good Idea!!!! "auto trans fluid and mix it with Acetone." !!!!!

SnowRunner98

I don't want to start a new thread for this, my drivers rear wheel is leaking--gear oil. TONS. I heard its prob a inner seal, and I have to redo my rear brakes. They need it anyway. does that sound right, and let me know what else I'm missing on this runner. thanks.

eddieleephd

Huh is easy you need a big screw driver or seal puller and a pair of needle nose. 4 bolts and e-brake cable. pull the axle and exchange seal reinstall axle and new shoes. need also brake cleaner to remove old brake fluid. gear oil to refil rear end.

Ladythump

A Ford dealer is 5min walk from my house and the Yota dealer is a 45min drive to the city. Figured a dealer was a dealer and a rear end was a rear end.

In the meantime, here is their diagnostic:
https://www.yotatech.com/forums/f2/r...nostic-194569/

SnowRunner98

cool thanks I have most of the parts besides the bearings. Heard might as well when i have it all tore apart.