Gear Whine after regearing

Neither is setting it by feel...but here you are.

 

With the installers experience and with the very slight whine I have and given a year Warranty I'm not worried.
The guy had another Taco waiting to be geared after mine.
mobilegearinstallers.com

Check him out

 

No measurements would have been a no-go for me. It makes troubleshooting and adjustment harder. I liken it to saying, "I'm 100% perfect, the first time, everytime....by feel to a tolerance of +/- 0.05 mm."
Nope...no one's 100% all the time; not even with records and measurements.

 

If the backlash or the pinion depth were off any bit at all it would of showed up on the the pattern, which was as good as it gets.

 

Did they secure the companion flange when rotating for pattern?

 

[So noise can be due to nitro and/or installation. That's basically it.[/QUOTE]

YEP

 

Or the design of the vehicle (not limited to the rear end). We know that trucks with stock gears whine too. It’s a harmonics issue somewhere along the driveline that is being transferred to the cab somewhere along the frame to cab mounting points.

Good luck figuring that one out though. The TSB includes new leaf springs and cab mount isolators. Shouldn’t be an issue for anything 2018+ though. Some anecdotal evidence has shown that cleaning your leaf springs and coating them in fluid film reduces the noise. I haven’t tried that yet but might one day.

 

I put my truck up on a lift and used a stethoscope, definitely coming from the rear diff.

 

Totally understand that mine was too which is why we replaced the first gearset and all the bearings. I think that there likely is some noise but it is amplified by the way the vehicle is designed. One thing we know is that stock gears in these trucks whine as well. Some worse than others.

 

I’ve got Nitro 4:88 and they whine too. Had mine done by Sierra expeditions. It’s a noise like an old car with a transistor radio. Lightly on throttle and off throttle at certain speeds. I verified everything before the diffs were closed up and got all measurements. I was also told and knew from researching that these gears will whine.

 

I wonder what secret sauce Toyota uses to keep gears silent (in most cases)?

My OEM gears make no noticeable noise. I wish we could buy factory gears in the ratios of our choosing.

 

Here's a good article on NVH analysis during gear design.
https://www.geartechnology.com/articles/0515/NVH_Analysis_Within_the_Design_Process/

As an aside, I've seen studies where reduced friction under higher speeds(elastohydrodynamic lubrication) can increase the NVH transmission characteristics in hypoid gears.

 

For the ones that do have whining from the gears, have you added sounded deadening material behind the back seats to see if it reduces noise? If did, how did it go?

 

So thicker gear oil may = reduced NVH?

I have not. I saw one post on that subject in all of my searching and the guy said it made no difference. It stands to reason that it should make some level of difference though (at least in my truck) because the noise is substantially less noticeable when the rear seats are up vs. in the folded down position. I do intend to try it at some point but have not had time to get to it.

 

Been tried; no dice.

 

I've set up many rear diffs that were spot on perfect with a dial indicator, new OEM parts etc and whined- some worse than others. All of the "cheap" sets whined.

What this taught me is: go with a better gear manufacturer (and even they had a bad set occasionally).

 

Martin from Mobile gear installers. He's Miguels brother from Premier west gears. He's done a ton of Tacomas. Just like Premier they don't use a dial indicator they do it from feel. I don't agree with t at all but the pattern was perfect. He told me he guaranteed the backlash was 6 thousands and the preload was 15 pounds. Like I said the pattern was spot on perfect.[/QUOTE]

The old adage "If you don't check your work, you can assume it's correct" is the prerequisite to most failures

 

Yukon 5.29's here. My rear gears whine a ton with light throttle at most speeds. Roar at 30mph and 70mph too.

Have been considering taking it somewhere to get the rear "re-assembled".

@Texoma said this in the 5.29 mega thread:

 

I had 4.88s installed and have the whine from about 53 mph to 60 mph.

I took my truck to Toyota to have the TSB applied. The tech I talked to confirmed the whine and said it could be addressed by the TSB, but since the truck was over 3 years old they wouldn't do it for free. It was going to be something like $700. To his credit, he told me it'd be a good idea to open a case with Toyota corporate to see if I could get an exception. I never did, though. That's the end of my relationship with Toyota's service department.

 

Are we now saying straight up Nitro gears are bad?