3rd Gen 4Runner…. The next thing

[Utah KJ]

I have a 1997 4Runner that I’ve driven maybe 1k miles in the last 5 years, and not at all in the last 1.5 years.
While my 07 Grand Cherokee CRD has been my primary ride, in the past two years l, it keeps finding new, and exciting ways to leak various fluids.
I figure I really should show DAVe (my 4Runner designation) some love. I made arrangements to have the shop I’ve been sending the Jeep to for repair.
I jump-started DAVe, and drove to the shop. With the exception of some very flat-spotted tires, it drove the same as it had.
There was a laundry list of items that needed attention. The last thing done was brakes (front and rear). After some time, I am told that I’m good to go.
When I arrived at the shop, the tech that was primarily working on it says, “we picked up a slight grinding in the brakes, we bled them over and over l, but no difference.”
I think that was my cue to say, “yeah, I know all about it, been like that for years.” But no, there was never a grinding. Not in the 14 years I’ve owned it, right up until my ride to the shop.
“Take it, and let us know what you think, we’ll take another look if you want us to.
I’m driving home, and am enjoying the ride of the rebuilt drive shaft, new CV axles, and bearings.
Then I come to my first red light, I hit the brakes, everything seems normal until the last 5 Ft. That’s when it grinds to a halt.
I pull into the gas station, and I text him saying it feels like the ABS is kicking in.
After I add some fresh fuel to the years old that’s been sitting in the tank, and continue home.
Before I hit the next intersection, the ABS light comes on, when I stop… no grinding. I text him the good news / bad news.
After work tonight, I break out my trusty paper clip, and proceed to count the ABS light flashes. I get:
Code 31
Code 33
Code 34
Which is front right speed sensor, and both back ones.
I share my findings with the shop via text. I offer as a possibility that maybe his guy forgot to plug the sensors back in.
He says they only ever unplugged the front right one. I’m going back to his shop tomorrow so he can hook up his super scanner to see if there’s any additional insight it can offer.

Have yous guys ever ran into a situation that would cause a false positive?
It’s hard to imagine 3 of 4 sensors suddenly going bad on their own.


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[thezentree]

I realize it's spilled milk but why did they have the sensor unplugged in the first place?

 

[4runnerteq]

Yeah. could Be they got a piece of trash in the sensor hole during install. And if they had to get rough in the very least it may be damaged. I see that pretty often. And I mean it doesn’t even have to take a direct hit. Banging near it can cause it to fail. Especially at 25 years old. Our shop has eaten quite a few over the years. Even though it was really our fault, collateral damage, but customers don’t take too well to that. “My antique truck wasn’t like that when I brought it in”. We usually just avoid the situation and replace before it’s picked up to save the hassle. It’s unfortunate, but it happens.

 

[Utah KJ]

Yeah. could Be they got a piece of trash in the sensor hole during install. And if they had to get rough in the very least it may be damaged. I see that pretty often. And I mean it doesn’t even have to take a direct hit. Banging near it can cause it to fail. Especially at 25 years old. Our shop has eaten quite a few over the years. Even though it was really our fault, collateral damage, but customers don’t take too well to that. “My antique truck wasn’t like that when I brought it in”. We usually just avoid the situation and replace before it’s picked up to save the hassle. It’s unfortunate, but it happens.

Thanks for that, I’m at the shop now, I read this to them. They did see that the front right sensor had grease on it from when the replaced the axle and bearing.
My OBD port doesn’t seem to want to power their scanner. They were checking the fuse that last I saw. They just informed me they got it to work. The plan is to drive it and read the sensor speeds.


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[Utah KJ]

Ok, home from the shop.
This is what they found:

Front right sensor - this is the only one they pulled initially. There was grease on it, which they cleaned. They also discovered the gasket had swelled, preventing the sensor from fully seating. New gasket, and back in business.

The rears were in there pretty good. One of them they were pretty sure wasn’t coming out in one piece. They cleaned them, cleaned the rust out of the hole and remounted.

Then we did the paper clip deal, and pumped the brakes 8xs to reset the light. After a test drive, the light didn’t come back, and no more grinding. So we’re good to go.


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[Utah KJ]

After getting a new set of tires it was time to seriously test drivability without the flat-spotted, and cupped tires. Driving around town… it’s as smooth as a Cadillac. The real test: take it out on the freeway for the first time in 5 years. What ultimately cased it to be parked for the last year and a half was a terrible vibration that kicked in around 55mph.
Out on the freeway, it’s good to go up to 65mph. After that, a low frequency hum (very loud) kicks in. By the time I hit 70mph, it’s almost deafening. Let off the gas, the noise continues until it dips to 65mph and below.
There’s no feeling through the steering wheel, and due to the low frequency nature of the noise, it’s hard to say if it’s coming front or back…. it’s just everywhere.
This is what was done while it was in the shop:
Upper ball joints
Rear DS rebuilt
Front pass side wheel bearing (they insisted the others are fine)
Alternator & Batt
New wheel studs front PS (I had snapped two off).
New front brake lines
New brakes front and rear.
New CV axles

In my research, I’ve read that there’s a needle bearing in the front diff driver side that’s been known to fail in lifted 4Runners. I see the East Coast Gear Supply makes a bushing to address this.
I am not opposed to installing this, it’s not terribly expensive. I’m just having a head time wrapping my head around such a small part being the cause of so much noise. I’d also think that it would be easier to localize that noise.
Last night, I went for another test ride on the freeway. This time, I pulled over at a gas station, and took temp readings with my frick’n laser thermometer.
Unscientifically, I aimed it at the front rotors, and the rear drums.
Front Driver I got 184F
Both rears 110F
Front Pass 134F
When I went for another pass, I was not able to duplicate that high temp reading on the driver side so that could be human error, but it was about 10 deg warmer than the pass side pretty consistently.
Maybe this whole thing is completely irrelevant, but that’s what I got.
If this DS needle bearing in the diff is bad, would it generate heat through the CV axle to the point that the rotor is going to be warmer than the other side?

I really need this thing to be able to go 75/80mph again like it did when it was my daily. It’s key to allowing me to sell my Jeep. This is all super-lame.

 

[ThundahBeagle]

Front U- joint? Often that's felt from under the hump between the front seat and the dash, so it seems like its everywhere. Had it go out on a GMT 400 Blazer Silverado years ago. Good mechanic did it for 80 bucks back then.

 

[Utah KJ]

Front U- joint? Often that's felt from under the hump between the front seat and the dash, so it seems like its everywhere. Had it go out on a GMT 400 Blazer Silverado years ago. Good mechanic did it for 80 bucks back then.

I dunno. The front driveshaft just kinda free spins in 2wd. I did pump some grease into it yesterday before going on my 2nd freeway drive last night. There was no change in the noise.
I did order that needle bearing replacement. If the noise persists, I’ll tell them to remove the front shaft and test again.
I would be very happy if the problem goes away by installing the sleeve and/or addressing the front shaft.


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[ThundahBeagle]

I dunno. The front driveshaft just kinda free spins in 2wd. I did pump some grease into it yesterday before going on my 2nd freeway drive last night. There was no change in the noise.
I did order that needle bearing replacement. If the noise persists, I’ll tell them to remove the front shaft and test again.
I would be very happy if the problem goes away by installing the sleeve and/or addressing the front shaft.


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Yeah, mine was doing it in 2wd also. Wonder if I'm recalling EXACTLY whether mine was it front joint of rear shaft, or...

May it be a quick and inexpensive fix for you. But a quality one, too.

 

[4runnerteq]

In a word ”no”. 3rd gens are not bad at all with a lift of no more than 2 to 3 inches. I would still suggest a diff drop. The needle bearing they offer we have installed in a 2nd gen Tacoma and 5th gen 4runner. Did not help the slight noise some of them make with the lift. Run it on a lift if you and see if it will make the noise. Check the u joints to make sure you don’t have one trying to seize. If the lift is recent it make take a bit for the driveshaft to get used to the new angle. Mine did. Make sure to grease the joints well also. It’s possible you have a pinion bearing going bad, but they will usually stop make noise immediately after letting off the gas.

 

[Utah KJ]

In a word ”no”. 3rd gens are not bad at all with a lift of no more than 2 to 3 inches. I would still suggest a diff drop. The needle bearing they offer we have installed in a 2nd gen Tacoma and 5th gen 4runner. Did not help the slight noise some of them make with the lift. Run it on a lift if you and see if it will make the noise. Check the u joints to make sure you don’t have one trying to seize. If the lift is recent it make take a bit for the driveshaft to get used to the new angle. Mine did. Make sure to grease the joints well also. It’s possible you have a pinion bearing going bad, but they will usually stop make noise immediately after letting off the gas.

The lift is many years old. This guy was my daily when I lived in UT full time, sea level hasn’t been kind.
It was many off-road miles of desert, never a problem. In FL, never had it offroad, and issues started happening
The part already on its way so, can’t harm anything putting it in, I guess. My issue is the guys I’ve been working with are very good, but they will not take a vehicle out on the freeway for a test drive. I don’t know why, they just won’t.
So I have to do the testing, and let them know what I find. It’s frustrating, but there are no good techs down here.


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[4runnerteq]

The industry has caused the tech shortage, along with the customer. But thats a whole nother topic all its own.

Not much to changing it. Cant hurt for sure.

 

[Utah KJ]

Somewhat of an update, DAVe is stuck in the cue behind some Mercedes they can’t seem to get out of the shop, so limited lime was spent in diag.
The tech did drive it up to speed, and heard the scary noise that I did; he felt it was coming from the rear. He checked the rear diff, and found the oil to be very low. It’s been tipped off.
The thing that really concerns me now is he mentioned that when he friend to go faster than 70mph to see if the noise would subside, he could only get it up to 71mph. This hasn’t been the case, in the past, but it’s been a good 5 years since this vehicle has been on the freeway.
It could be a clogged filter or injectors, but it’s not displaying any other symptoms of that.
Maybe it’s a clogged cat.
Maybe it’s the trans, and the top speed and the noise are one in the same problem.
They were ready to put it on the lift during my visit last night, but the Mercedes they thought was done, wasn’t. Lame.


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[Utah KJ]

I the wee hours of the morning, I got a text, ‘4Runner is fixed, it’s smooth as glass up to 85mph’.
They replaced the knock sensors (did I mention a code for sensors kinda comes and goes?), and that address the issues.
I went over to pick DAVe up, and went for a drive out on the freeway. I guess the majority of the low-frequency droning that I heard was the engine being retarded (no, seriously) due to the knock sensors.
I would not call it ‘smooth as glass’, and there’s still something, rotational sounding happening at 70mph.
The part from ECGS was not installed…. maybe that would clean it up more. Maybe the quiet, and luxuriant ride of my Grand Cherokee has spoiled me, and I’m being too critical.
I was able to take an extended drive and freeway speeds for the first time in 5 years, and will be going to work with DAVe tomorrow.


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