gearbox whines in 4th

[wolfswest]

Hi guys,

I’m looking for some advice.  Since a long time, in fact as long as I can remember, I’m having this annoying 4th gear whine…  Probably a common problem with our gearboxes?
I’m not a gearbox technician but probably a worn bushing, syncro whatever.  
I will pull the engine and gearbox eventually someday but I’m not exactly excited about this exercise because the car is running well.  It shifts real smooth and most of the time I don’t cruise very often for longer distances on the highway.  It’s a weekend warrior, fun around town kinda car.  

But, DasDragDay is coming up and that’s a 280 km drive for me so I’m looking for some advice to make the trip easier on the ears.  Are there any old school tricks out there to reduce the noise?  Most of the whine is noticable when I cruise around 3100 RPM and when I let go the accelarator pedal.

-Specific oil?  Thicker oil?  If so, what types do you suggest?
- “magic” products, additives?  Experiences with them?

Anyhow, I know this will not cure the problem but I’m looking for some easy to test redneck options…  

Thx,

Dem

[LGK]

There is no real "additive" or "magic product" that will solve the noise when going "off pedal",it's very common with a high power engine and mostly due of a the fact that the R &P is getting a little "loose",the more power the more noise you will experience on the gearbox when decelerating.
Try to go "off pedal" in 3Th gear you will hear the same noise,it has for 90% sure  nothing to do with the 4Th gear,syncho,or whatever.It's very rare to find a 4 gear bearing worn out,or they should be running whitout oil in the gearbox...but again without oil,then you're axles are worn out and spiders locked up before the bearings goes out





Cheers steve

[wolfswest]

There is no real "additive" or "magic product" that will solve the noise when going "off pedal",it's very common with a high power engine and mostly due of a the fact that the R &P is getting a little "loose",the more power the more noise you will experience on the gearbox when decelerating.
Try to go "off pedal" in 3Th gear you will hear the same noise,it has for 90% sure  nothing to do with the 4Th gear,syncho,or whatever.It's very rare to find a 4 gear bearing worn out,or they should be running whitout oil in the gearbox...but again without oil,then you're axles are worn out and spiders locked up before the bearings goes out





Cheers steve

Thx Steve.  Earplugs then? 

[nicolas]

yep and drive faster, that makes the trip shorter in time. 

[Eddie DVK]

There is no real "additive" or "magic product" that will solve the noise when going "off pedal",it's very common with a high power engine and mostly due of a the fact that the R &P is getting a little "loose",the more power the more noise you will experience on the gearbox when decelerating.
Try to go "off pedal" in 3Th gear you will hear the same noise,it has for 90% sure  nothing to do with the 4Th gear,syncho,or whatever.It's very rare to find a 4 gear bearing worn out,or they should be running whitout oil in the gearbox...but again without oil,then you're axles are worn out and spiders locked up before the bearings goes out





Cheers steve

This is bizar, nobody told me this, but heared it too a few months a go.
I am alwyas talking to my friends my gearbox is shot, because on the highway when I go of the gas it wines like hell. (only in 4th gear, have tried to go of the gas in 3rd gear but there is no whinning)
Try to replace it with a nother one i had lwying, but that one was realy broke. so changed it back, till some of my friends said the wine is normal with high powered engines.......
I was like, whaaaat ok.
So learned to life with it.
But can somebody tell the reason why t is winning?

Regards

[Felix/DFL]

There is no real "additive" or "magic product" that will solve the noise when going "off pedal",it's very common with a high power engine and mostly due of a the fact that the R &P is getting a little "loose",the more power the more noise you will experience on the gearbox when decelerating.
Try to go "off pedal" in 3Th gear you will hear the same noise,it has for 90% sure  nothing to do with the 4Th gear,syncho,or whatever.It's very rare to find a 4 gear bearing worn out,or they should be running whitout oil in the gearbox...but again without oil,then you're axles are worn out and spiders locked up before the bearings goes out

Cheers steve

This is bizar, nobody told me this, but heared it too a few months a go.
I am alwyas talking to my friends my gearbox is shot, because on the highway when I go of the gas it wines like hell. (only in 4th gear, have tried to go of the gas in 3rd gear but there is no whinning)
Try to replace it with a nother one i had lwying, but that one was realy broke. so changed it back, till some of my friends said the wine is normal with high powered engines.......
I was like, whaaaat ok.
So learned to life with it.
But can somebody tell the reason why t is winning?

Regards

I am no gerabox expert  but what I learned is that too much play between ring & pinnion and it whinnes. Had a gearbox were the play was not set up correctly and it whinned badly, same parts better play/thrust setting and there was silence.
Often the r&p bearing get`s play, even had a problem with a so called stronger / crapy side cover, which was softer than the orig. The bearing smashed in the side/play and there comes the sound...
When everything is setup correctly (sometimes not the VW specifications) / new bearings / box mods etc. there is no whinning with a stroker.

[Bruce]

If the ring gear backlash is too small, they tend to make noise.  I try to set the backlash to the upper end of the spec, this makes them run quieter.
In my own gearbox, the backlash is below the min spec.  It is quite noisy on decel.

[j-dub]

Bruce,
Does that indicate that over time the ring and pinion noise on deceleration will get better as the gears wear and the backlash increases? Or does the backlash not really change much on a transmission between services.

The reason I ask is I recently had my box rebuilt and I had my 412:1 swapped out to a 3.875:1(aftermarket) and I have noise on decel for the first time. I have no idea if it is setup or the aftermarket ring and pinion.

Thanks in advance,
Jeremy

[Bruce]

Noises never go away by themselves, you should know that  
Gear teeth don't wear.  They are good until they fail. 
My own gearbox has 100k km on it.  The noise hasn't changed since I built it.

Is your new 3.88 a China gear set or Brazil?
It could be the setup causing the noise, but to know for sure, I'd have to see the contact pattern. Are you planning on removing the gearbox from the car?

[j-dub]

I am guessing China however I am not sure, it is what the builder sourced. I have not decided if I am going to pull it out or not, it may be just something I have to live with. It is also leaking oil out of the nosecone, it seems to be either coming form the reverse light switch or the weep hole. Replacing the reverse light switch did not help, and I can't see anything with it in the car. I may pull it just to verify where the leak is coming from.

[wolfswest]

Thx for the replies guys.
I went on a 600 kms roadtrip this weekend and listened to every sound in the car for a few hours.  Like Steve said it also whines a bit in 3th but barely noticeable / annoying.  In 4th it just whines on decal and also on steady speed around 3100 rpm till 3600 rpm.  Under 3000 rpm it’s not annoying and above 3800 rpm it also “stops” or becomes less noticeable…  But, on the highway I normally run the car between 3200-3600 rpm…  damn!

Last week I isolated the car a bit with fake dynamat material.  It’s better then before but still noticeable.  Although I wasn’t exhausted, it was bearable.  I raised the front a bit and the car rides so much smoother!  Less nervous.  My plan is to focus the next few months on the driving aspect of the car.  I want to upgrade the rear brakes to disc brake setup.  Align the car 100% and add more dynamat material, in the doors etc.

[Andrew]

Thx for the replies guys.
I went on a 600 kms roadtrip this weekend and listened to every sound in the car for a few hours.  Like Steve said it also whines a bit in 3th but barely noticeable / annoying.  In 4th it just whines on decal and also on steady speed around 3100 rpm till 3600 rpm.  Under 3000 rpm it’s not annoying and above 3800 rpm it also “stops” or becomes less noticeable…  But, on the highway I normally run the car between 3200-3600 rpm…  damn!

Yes, this sounds like a familiar pattern to the whine on mine, happens on over run in 3rd and 4th.  Drop the clutch and coast and it goes much much quieter.

At highway speeds on about 3200-3600 rpm I get a sort of ner-ner noise in the background that becomes the whine on deceleration.

4.125:1 r&p , 3.78 , 2.35 , 1.48 , 1.04 built over10 years ago by a company called Transwest in the US about 16 years ago,  I would guess it has about 10k miles on the box.

[axam48ida]

Aftermarket gears! Nothing is as quiet as stock gears. Your 1.04 is not stock, alum side covers trans mit it and how is the trans mounted. Rubber or solid mounts. Also if your using rubber bus mounts they transmit any little noise also.

[Andrew]

Can't say I know much about the box, it seems able to take a bit of abuse as it's been used on the strip.

"Built by Transwest in 2001-ish has 4.125:1 r&p , 3.78 , 2.35 , 1.48 , 1.04 , one-on-one midmount, standard grey mounts,  gusseted, sideplated etc"

That's about all I have, according to this, http://www.thegoldenbug.com/en/vw_technical_articles/d70/vw_beetle_gear_ratios, it looks like almost none of the ratios are stock.

Could be a late model 1st gear with a stock R&P and the rest are all lower ratio, right?

Given when its was built what's the likely origin of the parts?

I guess the mid mount is transmitting all the noise up into the cabin.

I'll look and see if I have any more info.

Andrew

[Andrew]

The only other thing I found was a name scribbled on a slip of paper in the car's history file.

It leads me to here https://www.instagram.com/trnzwst/

Andrew