Update:
So if you have read this thread you should know that after my last visit to the service center, my car is left with 2 issues that I had to deal with. Lets go over them:
1. Original issue: There was a humming noise, sort of some kind of friction, while taking turns at slow speeds.
2. Left front suspension started making noise every time it goes on bad patch of the road. This was courtesy BUB Pune while working on the original issue.
How the issues are resolved: 1. Original issue: So after my last visit to the BUB Pune, I was heart broken to know that instead of one I will have to deal with two issues now.
The issue as I said was a humming noise when I take turns at low speed. I started asking myself below questions:
1. There is this noise only while taking turns
2. Only at low speeds, ideally only when the car is in 1st and 2nd gear
3. No noise while going straight
4. Parts which might be the culprit: Tie rods, link rods connected to suspension, drive shafts, wheel bearings, steering rack, front struts and strut pads, front disc brake covers, discs and pads, 1st and 2nd gears/gear box, clutch as I might be pressing it on turns to change gears
So last time the service center had changed strut mount bearings as a probable cause and while doing so confirmed that strut pads are in good shape. So these 2 are out of questions now. Going by the above list, I started on internet which part causes which type of symptom. Prepared the list in order of least expensive items to be replaced.
I came across below post on internet and it looked like this could be the least disruptive way of checking it fixes the issue.
Even though it looks strange and might not be an obvious choice of troubleshooting, I thought lets start with this. the gearbox on Jetta has no guideline for transmission oil change at such low runnign (45K KM).
So last week I visited the service center again, this time asked a senior technician to accompany me and troubleshoot the issue. Thankfully it reproduced and we had a chat over the potential fix. He said this does not seem to be an issue with tie rods, link rods and steering rack.
Then I casually mentioned that I read a post on net about tranny oil, and he immediately said yes it could very well be the issue since there seems be some friction and load on differential/GB. He spoke about the load on drive shafts and lack of lubrication. Even though he said this is just his theory, this is the least expensive and disruptive thing to check out. I agreed as I had bad experience of these guys troubleshooting at my cost.
I told SA that I DO NOT wish them to do anything apart from oil change as I had decided that if this does not solve the issue, I will try out my friend's FNG for further troubleshooting.
2. Suspension noise: The front left strut has become weak and there is nothing that they can do apart from replace it. They were certain about this and said no troubleshooting required for this issue. I asked if changing only one strut is recommended to which they said that's not an issue since the right is quite healthy. Its a gas filled strut and costs 8K (Inclusive taxes). I dont like my car making noise apart from engine and HU, so asked them to go ahead.
The phone rings:
The next day SA called me up and gave good news about the solving the original issue. I asked him 3 times if they have indeed tested the fix again, to which he said the same senior technician worked on the car and confirmed its solved now. Half convinced I visited the showroom the next day and took a test drive for around 15 mins. Found out an emply plot and repeatedly took turns to see if its indeed fixed. Thank God, its indeed fixed now
So an hour that I spent on researching similar issues, has solved my problem as well. I am so thankful to the dude who asked one of the guys on one of the forums to replace tranny oil.
This issue could have been solved at 2K had the service center engaged the senior folk and had I read that post earlier. This has taught me that YOU are the best person to first logically narrow down the issue and then ask these guys to carry out the deed instead of trusting them from word go.
This ordeal did cost me: Mount bearings (4K) + Front strut (8K) + Tranny oil (2K) = 14K. Service center waived off the labor charges for suspension replacement as a good will.
I have driven around 50KM since then and I did not hear that humming noise so far. The car is running like a dream now and just completed 6 years of its life span. Fingers crossed
People who complained about same issue on this thread: Please change tranny oil first and see if it solves your issue too.