So I've done some searching on this site about gear whine from the rear end and found that everyone says its on its way out and needs replacement...

In my case, I've got a '90 4Runner V6 5spd that I've had since '92. Its been whining since day 1 of me owning it (that's 15 years) and I've never had any performance trouble with it. I have about 140K miles on it now. I'm running Lucas sythethic gear oil in all gearboxes.

I'm about to go through a 3.4L swap, and I just want to evaluate the condition of my drivetrain. What's everyone's opinion, is the rear end healthy even though it whines? Is this semi-normal for some trucks to have this? It is only really noticeable at 80km/h and above.

Shoot me you comments.

Thanks!

 

as darrell waltrip once said "we are gonna run the bitc* till she blows" if you have that many miles and no problems. i would just do as darrell says.

 

i have the same problem in my 92 2wd toyota pkp. i beleive it to be the wheel bearings on the axles. i worried about it for a while but i have been driving it for a year like that since i bought the truck. it doesnt get any louder so i will keep on truckin. if it is a roaring sound from the rear i would worry maybe diff bearings or pinion bearings but if it is whining its probably the axle bearings. but this is only my opinion.

 

does the sound change from on power to coast?

If so, it's probably the setup. It's way too late to do anything about it, the gears have seated themselves. Is what it is. Run it.

 

I had a rear pinion gear get pitted out and make a bad whine, they were Geniune (crap) gears though. Never had any noise with the factory gears or the US gears I have now.

 

Yeah it changes from power to coast - definitely gears, not bearings.

Thats what I was thinking, its been good for 15 years, lets see if I can get another 15. I'll just get some better sound proofing for the cargo area so that the back seat passengers don't complain too much (I use it to carpool to work once a week).

 

There are some additives you can put in the oil that are supposed to help it "stick" to the moving parts and reduce whine, but I have no idea how good [or bad] they are. Check crappy tire oil aisle... other then that a small amt. of whine is normal it's when you get that grindy cogging noise that you want to worry lol... something else the synthetic oils are generally "thinner" for a given viscosity rating then the equivilant dino oil you might try switching to a dino based oil at the expence of changing it more often then the synthetic...
just a thought... aviator

 

Get louder speakers. thats what i do

 

the rear on my '93 started to whine at about 170k kms. it had never done it before. I couldn't afford the $ to have it checked out so I kept driving it and didn't run into any problems with it for 2 years (~20k kms) before I sold it. it didn't get any louder over that time either

 

My luck that would happen about 1000 miles from home in the middle of Moab or somewhere.

 

Is there any play in the pinion flange?

 

There has been a whine in my rear diff since I bought my '93 4Runner a year ago. It only whines between 60 and 75 mph, and only on the drive side of the gear... it doesn't whine in coast. I attributed it to funny gear wear due to a poor or loosened set up prior to me owning the truck.

When I first got the truck, the pinion seal was leaking and the pinion flange was loose (great... who knows how long the P.O. ran it like that). I replaced the pinion seal and re-tightened the pinion flange (I know... not supposed to re-tighten a crush sleeve after its initial installation, but it was only temporary).

A few months ago, I finally tore into my diff for fun when I had to remove the axles to change the bearings and seals. I found uneven wear on the inner pinion bearing rollers and race (no surprise since the pinion was run loose for a while). I also found no preload on the carrier bearings (but the carrier bearings themselves looked fine.) I also found the backlash to be a little too loose, and the pattern showed quite a small contact area on the drive side of the teeth. There was no visible uneven wear on the ring and pinion, and since it's a 4.88 gearset and 3rd member, which would require I buy the gears from Toyota, I decided to re-install the same gears when I set up the 3rd.

So I replaced the inner pinion bearing with a new one, and set up the gears with the right backlash and with proper carrier bearing preload. My pattern was much better than the as found pattern. I replaced the crush sleeve with a solid spacer, set the pinion preload, and torqued the pinion nut to close to 200 ft-lb (red loctite used and nut was staked... it's not going anywhere.)

Anyways, to make a long story a bit longer, my whine is still there, but it's much, much more quiet than it used to be. When gears are worn funny and start to whine, there's very little you can do to make them quiet again. However, I am confident that I got as good a setup as I could have gotten with the used gears, and I fully expect them to last as long as the truck does (which I'm hoping will be at least another 5 years if I can keep the rusting down to a minimum.)

 

You might try some sort of lube or grease that has a moly additive. I have read (might want to check on bobistheoilguy.com) that moly can actually 'repair' worn or pitted gear teeth to a certain extent.

 

Hmmm.....interesting.

I'm about to retorque the flange nuts at the t-case and diff's on my '86. They've been loose for a while. I hope there's no problems, but so far no symptoms. Anyway, I was under the impression from 4crawler it wouldn't be necessary to replace the crush sleeve just to retorque. Have I misunderstood something? The rear diff is leaking a wee bit, but no drip...just a wet casing. Same at the t-case. I understand that the leaking is from the loose flange, but I'm also under the impression that retorquing can solve that problem. Obviously I won't really know until I retorque them, though. Speaking of which, isn't the torque spec 90ft/lb's? Why 200?

 

You can re-torque the flange nut on a crush sleeve with probably no ill effect... I'm not entirely sure. The recommended practice is to replace the crush sleeve and start again (I suspect it has something to do with the range of elastic deformation of a sleeve that's already been crushed being different than the range of elastic deformation of a new sleeve?) If you happen to go too far when you tighten the new crush sleeve, you are also not supposed to back off the torque to lower your pinion pre-load. In this case, you are also supposed to start again with a new crush sleeve.

I don't believe there is a crush sleeve in the transfer case, so that shouldn't be a problem.

200 ft-lb is acceptable only because I used a solid spacer instead of a crush sleeve. With a solid spacer, the pinion preload is determined by the number of solid spacer shims that you use, not by the torque on the pinion nut. With a crush sleeve, the torque is closer to 90 ft-lb, but again, you adjust the torque until the crush sleeve gives you the proper pre-load on the pinion bearings.