Rear end knocking. Suspension.

Suggestions on what to look for when diagnosing a rear end knocking sound that only happens when turning rather aggressive with a change to incline. (Pulling into a driveway under moderate speed) Left or right turn. No other symptoms. No abnormal tire wear.

2004 Doublecab TRD with Manual hub 4x4 conversion.
Rear Leafsprings replaced a few years ago with a 5-pack. They have normal squeaking.
No other rear end modifications other than new brake lines and 1" lift blocks. U-bolts are tight.
Lug nuts are tight.
Spare tire is secure.
Nothing in bed loose.
Tow hitch secure.

Of course my thought is rear wheel bearings. About a year ago i checked them for abnormal axial play. There is a little but in the reading i did it seemed like some is expected.

How would you figure approach this?

 

Make sure all the bolts are torqued. shocks, shackles, leafs, u-bolts.

How SURE are you that it's coming from the rear? I know that it's often pretty hard to locate a sound like that. could be coming from anywhere, so maybe check the front, too.

Could be body mounts, too. You start throwing the weight around, *everything* is going to move.

Then, maybe just slow down.

 

how many total miles

what TYPE rear differential..........stock/modified

has it been regeared

outer wheel bearings wouldnt ‘ knock ‘

universal joints checked ??

 

Thank you.

196K miles on truck. I have owned it since 110K miles. Bone stock when i got it. California Car so no rust.
Agree hard to chase noises but pretty sure it is from the rear.
Slow down. Ha! I am not doing anything crazy but i will check my speed and report how fast i am going when the knock happens.
Entire front end was rebuilt when i did the 4x4 conversion. I mean EVERYTHING! (I have a whole thread on chasing lower control arms done wrong by a shop.) I will pay attention more and report.
Rear diff is stock. Rear axles are stock. I have never taken them apart. Only dropped them to install leaf springs.
1" lift running 5100 shocks.
U-joints were checked last year by drive shaft shop when i had the axle shortened. Will check again.

If outer wheels bearings would not knock then i will look at all my bolts again. The sounds is a metal knock for sure. Only happens when i pull into driveways at moderate speed suggesting a sideways load to the suspension. Truck tracks pretty well. Alignment done about a year ago. Truck not used offroad very much. Nothing radical. Just light trails a few times a year.

Will report back.

 

if all is stock.........drive shaft shortened ???????

was that part of 4x4 conversion

having checked U joints by someone else 1 year ago means Nothing NOW

is it a Torsen.....limited slip........Locker

a ‘ knock ‘ is usually a loose carrier bearing or bad pinion

 

i read somewhere that there is a slide feature like splines on a pto in rear half of the driveshaft. spring sag causes the rear dif to move closer to the carrier bearing and the slide bottoms out with a clang. idk i haven't got into that yet my self.

 

Knock is still there 18 months later. No better, no worse. 202K miles now on truck. Recently was under the truck and again put a wrench on everything and did a check of the drive line.

- All suspension bolts tight.
- U joints & drive line no play.
- No evidence of relative motion between parts that should not move.
- My rear springs are 5 leaf OME's with 1" risers. New U bolts. Shocks are 5100's. All installed about 20L miles ago.
- I do have a class 5 hitch and it is tight.
- Stock rear end with factory locker. Never been apart. Stock gears.
- Shortened rear drive shaft for my 4WD conversion.
- Bed has never been removed.
- California car with no rust and has never been hit.
- Running Gen 2 16" rims but have also run American Racer 16" too. Both with Rugged Trail tires.

The knock only happens when i go over uneven ground that puts the bed into lateral motion. (Side to side) Up a driveway, over speed bumps with one side of the truck etc. I will get a hard knock on the first swing then it decreases as the lateral motion attenuates. Two or three max. Very consistent, very repeatable and absolutely in concert with the amount of lateral motion. To me it is coming from the passenger side but it is hard to tell for sure. Definitely from behind me. My speed is probably 15 mph.

The only thing i can identify is that i do have some axial play in the axles. Not alot. I do not have radial play as far as i can tell. I have been told this is normal. Nothing back there has been take apart. No other symptoms like tire wear or pulling or anything else.

@ROAD DOG. When you have a bad carrier bearing or pinion would that not also show up under normal driving as the torque of the drive shaft loads the parts inside the rear diff? Not super familiar with this type of failure mode.

Anyways... You know when something bothers you and you just can't put a finger on it...

 

What do you mean by axial play? The wheel should turn by the amount of backlash, but not in any other direction. The rear wheel bearings are really easy to replace. Just go for it. Where in Socal are you?

Have you tried cleaning out the slip yoke? It's a common issue for the grease to build up in the slip yoke and hyrdo lock the yoke in place. Ya gotta clean all the old grease out, and just lightly grease the splines...

 

@Andy01DblCabTacoma what i mean is with the rear wheels off the ground i can push and pull on the wheel axially and feel some motion. Just a little. I have not checked it again in a while so this was a few years back. I was told this was "not abnormal" and to make sure i had no radial play. This makes some sense as deep groove/conrad bearings are radially pre-loaded and can have some axial play in them as the bearing balls are in an arch and only in contact at their apex points to the raceway. (Unlike angular contact bearings or four point gothic arch bearings.) I was also told that if the rear bearings were bad i would hear it when driving which makes sense to me as well. I think a special puller is needed to do this job. That has stopped me from just doing it.

When i installed the new drive shaft i did not do any special cleaning of the rear yoke where it slides in. I did not however notice any binding either when putting it back together. I will check that out though.

I used to suffer from "axle wrap" when i first got the truck. Knocking sound when breaking. That is why i replaced the rear leaf springs. That issue went away. I first went to 3 leaf units on a group buy. They broke probably due to overload. Then my current EMU's. The knock does not happen when braking.

I am in Huntington Beach.

 

So I had a clunk when pulling into driveways and on speed bumps. It does not appear to be a common problem but finally diagnosed it to an air locked driveshaft spline. When I removed the driveshaft, I could push in the yoke a bit but it resisted. So I cleaned out all the old grease (which is not easy) and lightly greased the splines. I don't think pumping grease into the back end of the spline is a good idea. Too much grease stops air from getting past the splines.

 

I'm trying to pick this apart- as you're using some slightly abstract names.

With your tire off the ground, the wheel should rotate (as in the direction of normal operation) ever so slightly (this rotation would be the same as the backlash in the diff). If it has any other play or movement, you have an issue.

You need more than just a special puller- you need a press and a puller jig to replace the wheel bearings. The reason I asked where you were, was if you were close by (San Diego), I'd have invited you over one weekend to use my press and tooling.

You BROKE a replacement set of leaf springs? How much weight are you carrying in your bed? Leaf springs shouldn't break (especially new ones). Are you doing anything which might have caused the springs to break prematurely? If so, it's more likely something like constant heavy loads, would wear the wheel bearings as well.

 

I had a very similar clunking, metal on metal sound that would manifest making turns that had a slight elevation. You mention having the Old Man Emu leaf springs. I would look at the front/main eye bushings on your leaf springs and see if you can see any evidence of the front of the leaf spring popping against the hanger. I had that issue a year or two ago and the solution was replacing the front bushings on the leaf springs. Check out this thread:

https://www.tacomaworld.com/threads/change-the-front-bushings-in-your-dakars.479071/

 

Do your leaf springs have all the plastic pads or silencers between the leaves?
I remember when I but my progressive aal on and one of the plastic silencers came out, I would get a popping clunk sound. I replaced all the silencer pads on the original pack and the noise went away.

 

Just a couple thoughts/ideas:

Since replacing leaf springs, have you retorqued the u-bolts? Don't loosen them of course, but I'd re-check that they're torqued to spec. 72ftlb if I remember right.

I would also recheck your u-joints, a lot can happen in a year. A friend of mine had a pretty weird knocking sound as well. His u-joints were shot; one was worn down to the grease channel.

Long shot, but is your spare tire loose?

As @Andy01DblCabTacoma said, you should not have any lateral/side-to-side play in your rear wheels.

 

@Andy01DblCabTacoma

I will check this out but the motion i felt was axially. In and out. Not rotational lash. I of course was not looking for lash so i will test that.

Yes. For a time i was hauling dirt for my dad's planting hobby. We would fill the bed up. It would bottom out the rear end. The drive was only a few miles but i am sure that broke the leaf. Could it have damaged the bearings. Maybe. I will take another look at the rear end.

Thank you for offering your tools. I may just have to buy the puller. The press i have.

@alexh Thank you. I do not recall cleaning out the yoke nor having issue installing it. Will look.

@CrustyTaco Thank you. Read the first post and a few follow-up posts. I agree the leaf springs are not quiet and i for sure have "wear rust" showing between the leafs. I have checked the bolts on the springs but did not look at axial shifting. The way you wrote that post it seems you could see the bushing shift while the spring was in the truck still? I will look at mine.

 

I could never replicate the issue with the truck stopped. I even drove around once with a GoPro pointed at the spring and wasn't able to document the spring shifting. But in my case, the front of the passenger spring would pop to the right and hit the right side of the spring hanger. Eventually after driving a bit it would slide back towards the center of the spring hanger. I was able to see some paint that had rubbed off the inside of the spring hanger where the spring had made contact with the metal. I would look for that. And it also may be worth taking a picture of the spring before driving and then maybe after you hear the pop and see if it has shifted. Good luck, it took me several months to track down the issue.

 

You should not have any in and out movement on your rear wheels (or front for that matter).



The bearing case (and therefore outer bearing race) is attached via those four bolts pressed through the backing plate and attached to the axle housing. The only thing the axle shaft itself touches is the inner bearing. If you have notable in and out movement here, the bearing is shot. Edit- or those four bolts are loose.

 

Thought i would give an update. The knock has persisted and mainly only is when i pull into a driveway at an off angle or in other words not straight in. The off angle entry creates a side to side motion in the rear end and you get the knock. One maybe two knocks.

Replaced my rear brakes today and measured the axial play while i was in there. Drivers side is .019". Passenger side is .008". From reading the max allowable is .028". I have no radial play that i can detect. Looking at the new axle bearings i picked up some time ago they seem to have axial play in the .005" range. I know some axial play is expected and going by the .028" spec it seems i am still OK.

Again nothing i can find in the rear suspension or the drive shaft.

Anyways...

 

I'd plan to do your rear wheel bearings. I had identical symptoms on my '03 Xtra cab, tried new leaf spring bushings, then later new leaf springs altogether w/ new ubolts, all to no avail. Finally just tried the rear wheel bearings out of desperation (despite my axial play seeming to not be that bad).

And voila, after the new wheel bearings the problem was immediately solved, and hasn't come back nearly 8 months later.

Edit: also I'd bet your bearings are far worse than the axial play you notice now (with the rear end assembled) would lead you to believe. I could shake mine in my hand like maracas, and they clicked back and forth a lot.

 

Thank you @Red_03Taco. I was debating if i should just go for it but also did not want to open a can of worms. I have the parts and press tool for job but was hesitant after watching a few videos on the job...