Speaking of Noises (Rear Diff)

[cary]

Speaking of noises, do any of you have a rear end that whines on the freeway. I have found that mine sounds like the drone of A/T tires on the freeway at about 70, and if drop off the gas, the noise decreases. It is not that loud, but I was wondering if others have the same thing?

Cary

 

[landtoy80]

Get MT tires you will never hear the rearend again
Its not the hum that pulsates is it?
kurt

 

[cary]

No pulsating, constant hum/whine. Sounds exactly like tire noise except it lessens when you coast.

Cary

 

[landtoy80]

Pinion bearing?
kurt

 

[bkgiii]

Cary:

Yep ..same noise hear...sounds like tires, constant 'roar', and 'tone' of noise drops when decellerating. My tires are Goodyear 295 70 16's.

 

[AZcruiser]

Probably pinion bearing(as kurt mentioned). Mine was not so bad but now it is loud and irritating. I had a shop check it out pinion bearings and side bearings need to be replaced. One of my upcoming BIG projects. Do you have any movement(about the axis) in your drive shaft?

chris
94LC

 

[cary]

I haven't checked it that closely. I figured that it was either a bearing or the gears wearing causing the whine. My solution, put redline gear oil in and leave it until it starts getting louder. I have seen these things where they will go 100,000 miles without getting worse.

Cary

 

[Hltoppr]

Anyone done the pinion bearing before? Speak up! I looked at the FSM for my 1992 and you can't even reach for a #6 without a special Toyota tool! :-\

-H-

 

[AZcruiser]

please speakup, pinion and side bearings is a task I need to do very soon. I havent seen much info on this specific rebuild.
Thanks
Chris
94LC

 

[landtank]

I had everything done when the gears were changed. Had a LC specialist in the area do it. He did mention that the pinion bearings were do and that the fact that he had to repeatably press on/off the bearings to adjust the gear alignment was a major PITA. This was done at around 95k.

I do have a whine of sorts which is getting louder with mileage. I now have 55k on my BFG AT/KOs

 

[cary]

Just bringing this back up, my mechanic noted that the rear diff fluid came out looking really used up (he said it looked like the stuff that comes out of his race car) when he repacked the rear bearings. The whine has gotten a little bit louder on long trips, so I think I am going to try some Redline 80w-140 to see if it quiets it down.

 

[Cruiser804]

i recently installed a used locker carrier and noticed this noise also. Starts at about 55 and stops about 65, and only when I have my foot on the gas. As soon as I let off it stops.

 

[Brian Macgyver]

Sounds just like mine did when the pinion bearing went. The noise came on pretty quickly. It was pretty noisy and would get quiet when I let off the gas. When I left Prescott for Phoenix, (second trip in a week) it was fine. That is 100 miles each way. By the time I got back it was really easy to hear. Here is what I did;
I removed the rear drive shaft, rear axles and the rear diff. I covered the diff and axle openings with wooden caps made on my saw and pressed the CDL switch. Then I drove away with front wheel drive like a really big Honda! I took it out on the highway to make sure that the noise was really gone with the rear end removed. It was.
In FWD, I drove down to my brother's shop in the city, carrying the diff in the back. We looked at it and decided to order a new pinion bearing. We got a Timkin bearing from Curt at Cruiser Outfitters that is stronger than the original. We are both old Jap auto techs, but neither of us had ever done any diff work. We were winging it in every way. Once the bearing was ordered, I drove back home with FWD.
Two weeks later when the bearing arrived, I drove back down. We rebuilt the rear end with a new pinion seal and a new crush sleeve. It was easy. Some of those who work on diffs for a living will act like it is rocket science, but it is not. We did not have to change any of the shims, or reset the backlash. We checked everything and set pre-loads at the high end of factory spec. We but it in a box and I drove back home where I installed it and put the axles and driveshaft back in. The only problem that we had was crushing the crush sleeve. We tried to tighten the pinion up with an impact, but ended up stripping the nut due to too much pressure. We were lucky in that a parts store had a nut from a Nissan front axle that fit perfectly. When you crush the sleeve, put the pinion and housing on the press and crush it almost as far as you want it to crush. Then tighten the nut and set the preload.
Note here that I logged 400+ miles over 2 weeks in addition to the driving that I did around home in FWD with the CDL engaged. It is not a problem.
The sure way to determine your problem is as I did. I serviced all of the wheel bearings since they were overdue anyway and a wheel bearing will make a noise similar to a pinion. Then I removed the rear end and the noise went away. With a fresh rear diff, the noise is still gone.
My brother, by the way, is toolsrus on this site. If you have questions, PM him or me.

 

[Cruiserdrew]

Pinion bearings do go south over time. It's normal in the over 150k range. My own take, is that this repair is best done at a differential shop. Pull the third yourself and save $500. Replace the pinion bearings, the carrier bearings and be happy for another 150k miles. You will especially notice the noise in the rear when decellerating from freeway speeds.

 

[cam75w/ls1]

Pinions will change noise on decel usually. If the bearing is bad but the preload is still good,meaning the bearing is still tight then it'll whine period. I'm setting up a rear on a 99 forerunner as we speak. It had a front pinion out at 167k. Cruiser804, your description of noise indicates an improper set up. You might want a diffrential shop drive your truck and see what they think. I remember years back(like 18 years ago) I set up a 10 bolt rear on a Chevy truck and it made noise like that and it lasted 8 months before it came back w/ no teeth left.

 

[CJF]

My whine's from the front. (Driveshaft removed to verify.) Been there for 100k.

Cary,

Let us know if the Redline actually helps out?

Curtis

 

[IdahoDoug]

My 93's done a slight whine since new. Previous 80 (1992) did also and the 97 also does it. Guess it's just all those gears, shafts and whirring bits. I've driven a 93 with failing front pinion bearings and even with gear oil in it, they get loud fast as Brian's experience shows. So, may not really be anything serious. I will say the '93 A442 has more whine on the freeway than the 97 and it's had fresh fluids and my anal care since new where the 97 I bought used.

DougM

 

[tommy854runner]

Similar noise here that is driving me crazy. Mine is more like a dull roaring at 73mph up to 80 from rear, that also make a quick buzzing metal on metal type noise when decelerating down a hill. I only have 94k on my 97 model so I thought it was a little early for a rear end but I guess not. I have already changed out the rear u-joints and have already purchased all the rear bearings and seals I just have to get my buddy when he's not busy to help me pull it apart. I already topped the fluid off and no change in noise. Let's keep this post going to see if anyone comes up with some real results.

 

[TORTUS]

Bump to keep it going:

I too have the buzzing/whirring noise during decel at highway speeds, getting ready to replace u-joints. Has this worked for anyone? Seems like I should wait until I pull the third and replace them then as it sounds like everyone is leaning towards the pinion bearing.

Has anyone solved this issue yet?

 

[john_eckels]

I have the same exact noise. About 70 mph, I get a low volume high pitch hum when accelerating. If I let off the gas or slow down to 65, it goes away. Im not going to worry about it until it gets worse.