Whining in reveres .

[dcmdon]

Dang, beat me to it!

Like @dcmdon said, it's the fact that the reverse gear is not helical cut, so they whine when in operation, completely normal.

In fact, nearly every modern vehicle uses straight cut gears for reverse for one reason, it's just straight up cheaper to make these gears, the only thing stopping automakers using straight cut gears in the whole transmission is due to the excessive noise. Since the noise is only present in reverse, a relatively short time driving, and quieter at lower speeds it's not an issue. It's also a nice audio queue that you're moving backwards.

Fun fact, straight cut gears are also much stronger than helical gears, so they are used in racing, BUT like I said, they make noise when in use, and they only GET LOUDER the faster you go. Here's the straight cut gearbox in the (extremely rare) BMW E36 M3 GTR. This car was basically a racecar that you could purchase straight from BMW, and let's just say I don't believe they would make great daily drivers.

At least it makes incredible sounds!

Yup. they are stronger.

They also dont' require as sturdy bearings. If you look at how helical gears mesh you can see that when you put force into it, there will be an axial force going along the length of the shaft. So helical cut gears introduce side loads into the shaft and the gear. This requires extra strength.

My 2004 Subaru STi had gears that were cut with very little angle. They were loud but with the added benefit that even if you built the motor up to 600 hp, the stock transmission could handle the power with no modifications. The sound was glorious.

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[Rusty PW]

Yup. they are stronger.

They also dont' require as sturdy bearings. If you look at how helical gears mesh you can see that when you put force into it, there will be an axial force going along the length of the shaft. So helical cut gears introduce side loads into the shaft and the gear. This requires extra strength.

My 2004 Subaru STi had gears that were cut with very little angle. They were loud but with the added benefit that even if you built the motor up to 600 hp, the stock transmission could handle the power with no modifications. The sound was glorious.

Did a trackday 2 years ago. Had a chance to drive a track prepped Viper with a straight cut sequential tranny. 800HP with that tranny was great. The noises coming from that car was something else. That car. You did your best times ever, or it tried to kill you.

 

[ShadowsPapa]

Goodmorning everyone. I have 2020 gladiator. Is it common to hear a whining noise moving in reverse? Thanks

I've never owned a stick that didn't due it, and like said - due to the gears.
Until about 40 years ago, even first gear was straight.

(reverse inside my T5) -

The automatics make a whine sound that's more from the truck's electrical system - some call that one "ghosts" and was discussed a couple of years ago here.

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