6th gear whistling...

[jpalmer1717]

Is it normal for an annoying whistle/ringing sound coming from the engine at 72-78mph in 6th gear? I love this car on the thruway...except for this noise that forces me to stay outside that speed range.

[BigJohn]

Is it Tire noise?
Some types of pavement will make strange noises with some tires.

[TX '90 ZR1]

I am normally not in 6th gear at those speeds. I have stock gearing.
But , none-the-less, I do not experience the sound you describe.
I would suggest determining if the sound is related to vehicle speed or engine RPM.
Let us know which and more suggestions will be forthcoming.

[jpalmer1717]

I also have stock gearing...when I downshift to 5th, the sound goes away. When do you normally shift to 6th?

[TX '90 ZR1]

Since the noise goes away when you downshift, I assume it is related to RPM, not vehicle speed.
Do you hear the noise when in 4th or 5th at the same engine RPM as in 6th? I'm thinking at 72-78 MPH you are seeing 1500/1700 in 6th?
I tend to not run steady at these lower RPM's. Prefer to stay "ahead of the curve". This normally has me using 6th very little as I'm running 85 or so before I get there.
If the only time you are hearing the noise is in 6th (not 4th or 5th) at low RPM it could be a result of wear on the gear or sync ring, but more likely a harmonic sound because of the drive train being in a "relaxed" situation with the higher ratio.
I wouldn't worry about it a whole lot as long as there is no vibration. How many miles on your Z?

[jpalmer1717]

Originally Posted by TX '90 ZR1

Since the noise goes away when you downshift, I assume it is related to RPM, not vehicle speed.
Do you hear the noise when in 4th or 5th at the same engine RPM as in 6th? I'm thinking at 72-78 MPH you are seeing 1500/1700 in 6th?
I tend to not run steady at these lower RPM's. Prefer to stay "ahead of the curve". This normally has me using 6th very little as I'm running 85 or so before I get there.
If the only time you are hearing the noise is in 6th (not 4th or 5th) at low RPM it could be a result of wear on the gear or sync ring, but more likely a harmonic sound because of the drive train being in a "relaxed" situation with the higher ratio.
I wouldn't worry about it a whole lot as long as there is no vibration. How many miles on your Z?

34,000 miles. Doesn't make the sound in any other gear. I think you're right. There is no vibration. I just need to hang out in fifth longer...till about 78mph. I love the sound of 6th at lower rpms on the thruway with cruise set. Maybe the answer is a good fuzzbuster. Do they still exist??

[32valvesftw]

You can stay in 5th until about 160mph I think.
But seriously when it makes the noise apply some pressure to the clutch pedal but not enough to make it slip see if it goes away.
Also find a spot where you can go faster in 6th and see what happens.
Do you feel any vibrations when tis is happening.
Have you tried driving the same rpm in 5th? Noise?
Try changing transmission fluid if nothing else helps.

[tccrab]

Funny, I've owned "Girlfriend" ('90ZR1 #792) for 15 years give or take, and I can honestly say.......I'm pretty sure I've never used 6th gear..at all.


TomC

[jpalmer1717]

Originally Posted by 32valvesftw

You can stay in 5th until about 160mph I think.
But seriously when it makes the noise apply some pressure to the clutch pedal but not enough to make it slip see if it goes away.
Also find a spot where you can go faster in 6th and see what happens.
Do you feel any vibrations when tis is happening.
Have you tried driving the same rpm in 5th? Noise?
Try changing transmission fluid if nothing else helps.

When I go beyond 78mph, and still in 6th, the noise fades out. I'm starting to think it is inbetween gears at this speed and a harmonic sound. Which is crazy 6th gear is that large. Maybe I'd be happier with a different gear ratio.......it sure makes sense considering I have no need for top end speed. I'm sure there are lots of threads on that topic!

[TX '90 ZR1]

Everyone will have their own driving style, but I think the engine feels better with some revs going on. Think of it as the engine pulling instead of being pushed.
For normal driving around I downshift at around 2000 RPM. This basically makes it a 4 speed with 5th there sometimes.
May not be the most effecient for MPG, but hey, supposed to have fun. If worried about fuel mileage I'll get a Prius!!
As suggested, I'd change the tranny fluid if you don't know for sure what is in there. These ZF's are a little noisy and the right fluid will make a difference,
Here's a RPM vs speed chart to compare. Credit Marc Haibeck for the chart.

ZR-1 ZF6 MPH 345 vs 410 gear ratio-Haibeck.jpg