Gearbox noises

[pnikas]

Hello everybody, I recently flipped a 914 tranny , replaced 1st gear dog teeth and synchro plus the input shaft bearing at the intermediate plate. Installed it in a beetle , it works really nice regarding the shifting but is making some noises I wished it didn't .
It does a slight whine the moment you take your foot of the gas pedal. Then it makes a kind of windy noise when accelerated on high rpm.
It does the most noise around 2000-3000 rpm. The replacement bearing I was sent was a bobo brand . I looked it up and appears to be a Chinese company making to order hard to find bearings. I have no issue with the brand since china products have surprised me an made me look like a fool before.
The main part is that I would hate to pull the engine and gearbox down again. More than buying another bearing .
Here is an audio of my case . on 3rd in the first let off the gas the noise is very noticeable .

https://www.youtube.com/watch?v=qYabycD7i2U

[jess p]

I listened to the video and a noise that gets louder when your vehicle is accelerating probably means that there is heavy contact of the pinion gear teeth on the outer ends of the ring gear teeth. Pinion gear not set deep enough. A noise that is louder when the vehicle is coasting means there is not enough tooth contact or too much backlash. I’m not familiar with bobo bearings made in China.
You are referring to the 2 side carrier bearings.
Dave mentioned about this special tool that is used to set backlash on these transaxles. I’ve seen a picture of the tool and the instructions on how to use it. I purchased the bearings from our host and they were not all all expensive but that’s been awhile ago. If you have two different noises on drive and coast then it’s not carrier bearings. Are your carrier bearings bobo?

[pnikas]

Originally Posted by jess p

I listened to the video and a noise that gets louder when your vehicle is accelerating probably means that there is heavy contact of the pinion gear teeth on the outer ends of the ring gear teeth. Pinion gear not set deep enough. A noise that is louder when the vehicle is coasting means there is not enough tooth contact or too much backlash. I’m not familiar with bobo bearings made in China.
You are referring to the 2 side carrier bearings.
Dave mentioned about this special tool that is used to set backlash on these transaxles. I’ve seen a picture of the tool and the instructions on how to use it. I purchased the bearings from our host and they were not all all expensive but that’s been awhile ago. If you have two different noises on drive and coast then it’s not carrier bearings. Are your carrier bearings bobo?

Hello , thanks for your answer .
The input shaft bearing on the intermediate plate is bobo .
The noise i am listening is more noticeable when I take my foot off the gas pedal . It doesent get worse with speed . It does it around 2500 most noticeably . This is why I suspected the input shaft bearing . Also noticed that when the car is stopped in neutural , engine to 2500 rpm . The gearbox is audible with the clutch non pressed . When you push the clutch the car completely changes tone .

Another question is what kind of movement should I get from the roller bearings next to the diff. They have some minimal movement but I supposed that this is normal clearance for oiling . It’s really minimal and the races looked perfect . Is there any case the input shaft is bent causing problems to it’s bearings ?