sharrack

i feel a thump or bump in the drivetrain when stopped at a light
with my foot on the brake . when releasing the brake i feel
a thump without touching the gas.
it does not happen all the time.
Any ideas?
thx! ks
99 runner/ 4wd/ v6/ automatic

JasonYota

iTrader: (1)

Sounds like the rear brakes sticking. You could try adjusting them and just see what kind of condition they are in. It wouldn't necessarily be the rears, that's just most common.

BlazeRunner

If it's not you rear drum brakes, it could be the driveshaft u-joints have some play in them and need to be serviced (greased) or replaced.

Robb235

I'm getting this too. Sounds like a thumping or knocking sound whenever I'm slowing down, whether I'm on the brakes or not. When I get on the gas, even lightly, the sound goes away, but comes back as soon let off the gas. I only hear it at slow speeds, and the sound speeds up and slows down depending on my speed.

I was thinking u-joints, didn't think about the rear brakes.

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sharrack

Yea..... Its got to be the rear brakes sticking while at a light with my foot on the brake.
As i release....a slight thump happens from the drivetrain.
I'll dig in and figure it out. Thx!

Kiroshu

Every early Tacoma and 3rd gen 4runner I've ever driven are like this. Its been a problem I've been hunting a solution to for years.

As stated in posts above sticky/faulty rear brakes could be the culprit.

Possible poorly serviced/lubricated rear propeller shaft.

Axle wrap.

Check condition of springs and axle mounts/linkages.

Shock absorbers..?

Robb235

I feel like mine is in the drivetrain somewhere. The brakes don't affect the thumping, it only happens when I decelerate. It goes away as soon as I'm back on the gas.

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famous4banger

has anybody found a solution to the noise? I have the same exact symptoms as Robb235, only at low speeds and only when not accelerating. mine is a click/thud type sound. I'm hoping mine is just the U Joint at the differential but im afraid it may be a rear wheel bearing for me.

Robb235

Haven't had time to look into yet, been busy with work. Hopefully this weekend I'll be able to dig into it.

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famous4banger

I found my problem. It was the U-Joint at my rear differential. I put my truck on the lift and spun the drive shaft and could actually see the u joint moving in it's seat, clicking against the flange. I will be Replacing it tomorrow after work. I'll post before and after pix as well as a video showing the failure to help you guys track down your problem if it's similar to mine. But note, on the ground, my u-joint acts like a perfectly operational driveline part, no free play no wiggles. In the air, totally different story. I could almost pull it off. She's spending the night at work until the parts come in. Good luck!

famous4banger

Ok well I replaced my entire driveshaft because it wouldn't balance to true. And guess what. Still clicking up a storm. I needed u joints immediately but they weren't making the noise. It is most certainly coming from the differential and sending the noise down the axle shaft to both wheels according to my boss. I will post back with results of the differential repair. The problem is, to remove my diff, I will have to also remove the axle shafts. I anyone here has done it, please let me know of any tips or tricks to make the disassembly and reassembly easier. Thanks!

JasonYota

iTrader: (1)

Pulling a 3rd member is easy. There are many write ups on here and other sites.

250000_yota

Sorry guys, just found this little post. ive seen this quite a bit in the last couple years. It's common enough that toyota released a TSB on it for the newer 4runners (03+).

It's the slip joint in the rear drive shaft. Over time the splines get worn, and pop when stopping, then brak free when starting back up. Lubing the shaft can sometimes get it to go away, but it almost always comes back, because by the time it becomes audible, it's already too late. Only sure fire fix we've found is to replace the shaft, or send it to a driveline shop to have it rebuilt, and have a new slip joint out in.

Hope this helps.!

ZUK

iTrader: (1)

famous4banger replaced the entire DS per his last post and says he still has the prob....worn slip joints might be related to it but I think the ROOT cause is something a little different. I'm thinking it's the carrier bearing in the middle of the 3 piece DS. The rubber gets weak over time and during slowdown the auto tranny power torques the DS up against the side causing a thud.....release the brake and BAM! it self centers back in the rubber ring. The solution would seem to be going to a 2 pc DS but that means money and a really long DS that is hard to balance. The guys with manuals do not have have this prob and that should be a hint as to why I think it's the carrier bearing. To test this, place the tranny in neutral before you do the slowdown at a light.....no more thud when coming to a quick stop. Also, it seems the thud is more pronounced when the AC is on and thats because the AC has raised the rpms some and the tranny is now offering a greater counter-torque when braking.
Some have also experimented with shimming the center bearing mount with Big thick washer plates and changing the angle that the CB works thru.
Ken

famous4banger

My 4RUNNER is stick shift. I get the sound pushing my truck in neutral even when the engine is off :/ it is very loud between 1 and 14mph but completely diminishes after 1st gear. I have no center support and a 1 piece drive shaft that I just replaced. I am going to be replacing the whole axle with one online that comes with the rear disc brake conversion already done as well as an E locker and I think lower gear ratio(mine is 4:30 I believe the new one is 4:10 but not sure, maybe vice versa) either way, $754 is leaving my pocket soon. If anyone has a totaled 4R rear axle or an old one laying around, Please PM me and sell it to me. I am in southern Orange County, California and I can take my loaner car from my shop to pick up the axle anywhere within 500 miles. I need my daily driver back to normal. Traffic is embarrassing down here, clicking and clanking by other cars sounding like my beautiful truck is going to drop both rear wheels haha. I'll look for the 3rd member write up. I can only get half the parts through my supplier though because we only service euro cars so I'll have to order the rest online.