100 Series: Steering Popping Noise

[AlpineAccess]

I've been having a noise gradually getting more present over the last 6 months on my 100 series - vehicle is at 205k now and it started around 200k. At first it was only when I was pulling up a driveway approach or backing off of one with the wheels turned (picture a 90 degree back out/90 degree pull in) where suspension is loaded and flexing. I haven't been driving a ton but the noise is now to the point where it is repeatable and consistent in getting the noise to pop up.

I know this will be a lot of detail, but hoping to help narrow the focus on this as much as possible:

1. Situations where it makes noise
a. It pops every time (usually twice) when flexing over a speed bump when one wheel hits the speed bump first, but not if I hit bump dead with both wheels.
b. Pops every time I turn into my driveway approach 90* turn in from the street and the vehicle goes up the approach.
c. New, and helped eliminate a series of options for me: When I turn left/right in a cul-de-sac and turn around; regardless of how tight or loose I make the turn it pops multiple times; 2-5 pops and then pops again when I straighten it out (holding the wheel in the same spot to create a steady arc).
2. The popping noise sounds more like a light pop (like tension being released)
3. I can feel some feedback in the steering wheel
4. It is definitely in the front end

In the last two years I have rebuilt the majority of the front end, which has me focusing on things that aren't new (but I've checked through the other items as well. I did push/pull test with vehicle up in the air and everything feels tight. It should be!

New in last 2 years:
1. Lower Ball Joints (555 units). Upper Ball joints (SPC as of just 6 months ago)
2. Upper and Lower Control Arm Bushings (all of them tightened at ride height including SPC ball joints)
3. New OEM CV's, hub flanges
4. Wheel bearings and races and all components refreshed new 2 years ago, repacked this winter and pretension, CV clips, etc. all confirmed to be done properly.

What I have done to try to narrow focus:

1. Eliminate drivetrain as part of the issue: Removed CV flanges and drove with CDL on. No change in noise, definitely doesn't look like CV's.
2. Did push pull test, lower ball joints, uppers, etc. seem solid and tight.
3. Greased SPC BJ's heavily.

The previous owner had a shop install a new steering rack at 145k with poly bushings. I can't find anything that says Toyota on this rack so its my lead suspect right now. The popping noise sounds almost like a tooth jumping? I see there is a nut behind the oil filter which looks like I can adjust the gear lash/pretension on the rack to test if its the gear popping. I would assume if is jumping that the steering would be off though.

I will try to record the noise soon!

 

[rover67]

I had a rack make a popping noise that turned out to be the actual rack or "shaft" in the rack assembly housing moving up and down due to the tie rods (which were angled up toward the rack) pushing the shaft up and down when the wheels had a quick load on them.

does that make sense?

Does the rack have any play in it? Like does the rack itself move up and down in the housing?

 

[AimCOTaco]

Good info, I can see why it's perplexing after all the checks and isolation testing.

I'm feeling rack also, the bushings in the end allowing the bar to shift up and down or a very worn and miss adjusted pinion seems like it could show up under these conditions. I've always assumed the rack gear lash would be most worn in the center and tighten up as we turn so I'd think.

I don't think T-bars or ball joints (or shocks) make sense given it does it both directions in a cul-de-sac where you're not unloading as you are on bumps or driveways.

Maybe the tie rods are loose at the rack? Inner tie rod joint bad?

I'd use helper at the wheel to slow wiggle back and forth while you carefully feel for slop across the steering system, maybe break traction on one side at a time, then both sides and keep checking if you haven't tried this already. (include the steering shaft and u-joints in your checks)

 

[AlpineAccess]

I had a rack make a popping noise that turned out to be the actual rack or "shaft" in the rack assembly housing moving up and down due to the tie rods (which were angled up toward the rack) pushing the shaft up and down when the wheels had a quick load on them.

does that make sense?

Does the rack have any play in it? Like does the rack itself move up and down in the housing?

Thanks for the input! I'm not super clear on the initial description of what could be going on internally, but just took a video with my phone in front of the rack while the wheels are on the ground, turning back and forth.

I don't see any movement in the rack on the cross member (maybe 1/4" for loading the bushings which is normal). I don't have anyone at the moment to hold the wheel in place but I took a video of the rack as well while steering and from what I can see every input I make in the wheel is being reflected in the steering (no, or minimal slop between steering wheel and rack).

 

[AlpineAccess]

Good info, I can see why it's perplexing after all the checks and isolation testing.

I'm feeling rack also, the bushings in the end allowing the bar to shift up and down or a very worn and miss adjusted pinion seems like it could show up under these conditions. I've always assumed the rack gear lash would be most worn in the center and tighten up as we turn so I'd think.

I don't think T-bars or ball joints (or shocks) make sense given it does it both directions in a cul-de-sac where you're not unloading as you are on bumps or driveways.

Maybe the tie rods are loose at the rack? Inner tie rod joint bad?

I'd use helper at the wheel to slow wiggle back and forth while you carefully feel for slop across the steering system, maybe break traction on one side at a time, then both sides and keep checking if you haven't tried this already. (include the steering shaft and u-joints in your checks)

Appreciate the help here - what is throwing me off on this specifically related to your comments on the steering shaft/u-joints is that if I'm static and turning there is no popping noise. Also, if when turning I hold the wheel in exactly the same position; I am still getting the popping.

Its perplexing!

I also took the tops off of my sway bar end links today to eliminate the sway bar binding up as part of this issue and found there was no effect.

Is it possible that when turning/flexing there is some kind of binding happening in a frame mount or something? I thought maybe, so I removed all of my skids too and no noticeable change. Am going to tighten up my steel bumper bolts as well just to check.

 

[Shuksan]

Certainly rack is possible. How loose/tight is your steering response. The inner tie rods could be popping in-out. Mine were bad on the non-OEM rack previous owner put in, but I couldn't get them to pop manually because I had too much play in old rack/OE type rubber bushings. However, they were clearly very very loose. If you think it is inner TREs I would just get a new OE rack, which comes with the inners.

Even though ball joints replaced within last two years, I wouldn't completely eliminate those from consideration. I had a similar clunk/pop sound and I did my ball joints within last couple years. However I had small to medium boot tears that I didn't address quick enough and the lower 555 ball joints were bad. Easy fix and certainly being lifted and wheeling will shorten lifespan on these.

 

[Stuckinthe80s]

Soooo.....I hate to even put this in writing but what you are describing sounds exactly what I was hearing when I blew my front diff in my 99. The noise came from the same situations you are describing and it sounded just like how you describe. I replaced a CV before I figured it out but nothing else. The tell tale sign was when I drained my diff and saw the chunks on the magnet.

I realize you have been hearing it for 5k miles now but again, I couldn't hear the clicking, popping, whatever you want to call it except on bumps and tight turns. I really hope that it's not the case for you but drain your diff to be sure.

 

[AlpineAccess]

Soooo.....I hate to even put this in writing but what you are describing sounds exactly what I was hearing when I blew my front diff in my 99. The noise came from the exact situations you are describing and it sounded exactly like you are saying. I replaced a CV before I figured it out but nothing else. The tell tale sign was when I drained my diff and saw the chunks on the magnet.

I realize you have been hearing it for 5k miles now but again, I couldn't hear the clicking, popping, whatever you want to call it except on bumps and tight turns. I really hope that it's not the case for you but drain your diff to be sure.

Thanks Nic! I'll dump the fluid tomorrow and give it a look!

What's weird to me is that when I pulled my hub flanges off yesterday and drove it around, it still made the noise.

I assume dropping the front driveshaft will help me eliminate the diff as a culprit?

 

[Stuckinthe80s]

Thanks Nic! I'll dump the fluid tomorrow and give it a look!

What's weird to me is that when I pulled my hub flanges off yesterday and drove it around, it still made the noise.

I assume dropping the front driveshaft will help me eliminate the diff as a culprit?

Yeah, even though there is no power getting to the hubs, the drive shaft is still turning the ring and pinion and IF they are damaged, you'll still here the sound.

I remember when I got everything put back together after replacing the CV, I had my wife back out of the driveway and start to drive so I could watch and listen. As she backed out I started to get excited about "fixing" the problem because everything looked and sounded fine. But when she turned hard to start driving down the street, I immediately heard the noise again and started a colorful string of curse words.

"Under certain circumstances, profanity provides a relief denied even to prayer." - Mark Twain

 

[AlpineAccess]

Yeah, even though there is no power getting to the hubs, the drive shaft is still turning the ring and pinion and IF they are damaged, you'll still here the sound.

I remember when I got everything put back together after replacing the CV, I had my wife back out of the driveway and start to drive so I could watch and listen. As she backed out I started to get excited about "fixing" the problem because everything looked and sounded fine. But when she turned hard to start driving down the street, I immediately heard the noise again and started a colorful string of curse words.

"Under certain circumstances, profanity provides a relief denied even to prayer." - Mark Twain

Just to confirm, even if I remove the hub flanges and the driveshaft, it may still pop?

 

[Stuckinthe80s]

Just to confirm, even if I remove the hub flanges and the driveshaft, it may still pop?

Oh, no, if you remove both of those, the ring and pinion will stay stationary and if that is the culprit, the sound will stop.

 

[AimCOTaco]

I hope Nic is wrong, it's Fri13 so he could be off. The only reason I didn't suggest the front diff was because I miss read thinking you'd fully isolated it. I'd try the no flanges no driveshaft test drive AND/OR check the drain plug magnet.... its sounding kinda diffy.

 

[AlpineAccess]

I will do this today as I have a little time around lunch! @AimCOTaco I pulled the flanges only; drove around and still got the pop the other night.

I've never wanted my steering rack to be bad before, but I certainly do now!

 

[Stuckinthe80s]

I think the 4.30 was in 98 to 2000 but I could be wrong. I’m positive about 98-99.

I was able to find a used diff for about $400 and that limped me along for a year until I got the other rebuilt with a locker. This was a few years ago but Cruiser Outfitters quoted me around $800 to rebuild the diff to stock specs. I ended up going with the ARB locker route because the truck was going to be the main family camping rig and I wanted peace of mind. I didn’t plan on wheeling it hard either but I didn’t think I was wheeling it hard when I broke it. Now granted, the break comes from shocking the system after most of the preload is gone from a lot of miles so a fresh unit should be plenty strong for most situations on 33” tires or smaller.

 

[AlpineAccess]

Well I pulled the front driveshaft and both of the flanges and drove around - the popping noise remains unchanged; so I am OK to rule out the front diff right?

One thing I noticed that results in multiple "pops" when turning is actually that the vehicle is "wallowing" in the turn as in it compresses/dwecompresses the suspension when twisting. But that led me to wonder, is it possible there is something non-suspension related that when torqued could be causing this popping?

So I am first going to try torqueing my metal bumper down as its easy enough to do.

Overall though, I'm probably back looking at steering rack or suspension components? This is an interesting issue.

 

[Stuckinthe80s]

Yeah, it shouldn't be the front diff then. WHEW!! I always get sick to my stomach when I hear about somebody going through that.

I would still drain the diff and look at it to be 237% sure. When is the last time it was done? I think it's 1.3 quarts so it would only cost you $10 or so. Okay, maybe $20 if you use the good stuff.

Do you have a go pro and a magnetic mount? You could stick that in several spots to see if you could see the popping when you recreate it.

 

[AlpineAccess]

Yeah, it shouldn't be the front diff then. WHEW!! I always get sick to my stomach when I hear about somebody going through that.

I would still drain the diff and look at it to be 237% sure. When is the last time it was done? I think it's 1.3 quarts so it would only cost you $10 or so. Okay, maybe $20 if you use the good stuff.

Do you have a go pro and a magnetic mount? You could stick that in several spots to see if you could see the popping when you recreate it.

I just can't imagine its the front diff (internally at least) - maybe a mount or something is possible. I had it fully disconnected and the popping noise did not change even a tiny bit. It was popping the exact same as it was prior to disconnecting everything.

I don't have a gopro, but am going to try taping an old cell phone with video on there and see if I can see anything!

 

[AlpineAccess]

Have continued to work on things today. Still getting the noise but here is what I've done:

1. Lubricated body mounts
2. Lubricated any metal on metal/hardware locations on aftermarket bumped that could be binding
3. Lubricated sway bar bushings.
4. Lubricated steering rack bushings
5. Lubricated upper control arm bushings
6. lubricated torsion bar mounts and splines
7. Removed front shocks and drove without them.
8. Checked torques on upper control arms.

I've done a lot of short test drives; about 1-3 minutes long around my neighborhood after each item and can get it to make sure same noise after each attempt.

Next up:

1. Lift vehicle and do push and pull AGAIN. I didn't put a pry bar under the tire last time so might haven't crossed lower BJ of the list.
2. Verify the torque on the replaced lower control arm bushings that I put in a few months back.
3. Drain diff fluid and swap to synthetic from the 80w90 that's in there.

Verified the following:

1. Steering rack was replaced by previous owner 60k ago. I can't find a Toyota logo on it, but called the shop that did the repair and they said they use Toyota remans. They are one of the top Toyota shops in Phoenix and maintained this thing for like 15 years (I have PO's maintenance records going back to day one of ownership and the guy was extremely detailed).

2. Front diff torque arm bushing is pretty shot. I went back through the records and found that I was mistaken in thinking the diff bushings had been replaced, so I pulled the bolts on the other two to look at them. Frankly I can't tell if they are bad or not, they look serviceable but the torque arm one is definitely towards EOL; so am going to order the arm.

3. I've got some slightly rust colored grease in my passenger side wheel bearing AGAIN within the last year. So I'll be doing a repack on that one when I find an axle seal this week.

 

[AlpineAccess]

Did push pull, everything seems tight. Should be, it's all new within last 15k.

Checked torque on lower control arm bushings. They were OK/in spec.

Drained front diff just to be sure per @Stuckinthe80s; all clear. Less than a pea size amount of sludge on the magnet in the last 30k with off road use and towing use included. Put synthetic in this time, usually just run 80w90 conventional. It is $18 a quart right now at advance auto. What the.

(The shiny spots in the photo are actually bubbles from draining, not metal flake)

 

[AlpineAccess]

Following up on this many months later as I finally figured it out in the last two days.

My Slee diff drop bolts were somehow loosening. I tightened them down and the noise is gone. It is an amazing feeling to eliminate such a specific popping noise and to find such a simple fix with no damage. Slee in their install directions shows 50ft lbs on these bolts. Mine had loosened to around 30-40 ft lbs.

I am going to remove the nuts and put locktite and redo it when I replace the diff bushing support arm in the next week. I cranked them to 70 ft lbs and am going to keep them at that higher torque spec.

Thanks to everyone who gave me ideas on what to check.

Also a shoutout to 100 series guy Paul in Centennial who I consulted and who helped me rule out a number of things. He too was stumped but recommended I just get under and start torquing things to spec which resulted in me finding these bolts. Every bolt I checked torque on I applied a paint pen mark to and just kept working across the undercarriage.