I have a Santa Fe 2015 4WD AT variant that has done 95k Kms. I bought it an year ago when it was at 75k. Except a few minor issues, the condition was perfect. The interiors and exteriors both were shiny new, the engine and gearbox were butter smooth (drawing reference from my Honda City IVTEC). I did around 20k kms in an year before I faced a major issue.
One day while stopping at a red light, I noticed vibrations while the car was on Neutral and brakes pressed. On releasing brakes, I could feel the car moving forward slightly. When I reached home, I checked again and the car was indeed having a forward momentum in Neutral and Park. While pressing the accelerator didn't make the car go faster, but there was a forward movement in Neutral (In park, it did lock but I could feel the movement before it gets locked). Next morning while trying to reverse from my parking, the reverse felt like a lack of momentum (otherwise it moved as soon as you let go off the brakes, without having much need to accelerate). On pressing accelerator, it moved but with jerks which were very more than noticeable.
So I called up the ASC (Garve Hyundai, Pune) and explained them the situation. They picked the car up and after inspecting, said that the ATF has not been changed since quite long, and changing the ATF may solve the problem. I gave them a go ahead after doing my research on ATF. They charged around 19k for the entire thing, and delivered the car back mentioning that the vibrations have reduced a lot, and told me that I can use the vehicle without any worry. I insisted that they diagnose if there is any issue with the gearbox, to which they said that the AT gearbox assembly is not serviceable, and if there is a problem with the gearbox, they will have to change the gearbox assembly, which will cost around 4 Lacs. So I drove the vehicle for few days and could see that the problem has not been resolved at all, with it behaving exactly the same way.
I then took it to a FNG. They said that ATs are difficult to repair. In similar cases, they replace the gearbox with another one from a donor vehicle if they are able to locate one. However, that will also cost a good sum of money. So I started doing some research and discovered that this is a problem that can be traced to AT solenoids, which are located inside the gearbox assembly. I found some youtube videos (links at the end of post) that showed how to diagnose and change those solenoinds and sent it to the FNG. They said that they can diagnose it, if I was okay with it. So one Sunday I went to them and we did the diagnostics, as well as cleaned all solenoids. (BTW, the ATF was completely blackish-brown, looked like ASC did not change it and just charged me for it
![Frustration](https://www.team-bhp.com/forum/images/smilies/Frustration.gif)
. The vehicle was not driven more than 200 Kms after the car came from ASC). However, all solenoids were working and none was faulty. After assembling, no change was seen in driving.
I am summarising all the symptoms at this stage below-
In Neutral, the car moves forward (however does not accelerate on pressing the accelerator). The engine feels under load and vibrations are higher than normal.
In reverse, the car does not move without pressing the accelerator. On lightly pressing the accelerator, it moves with big jerks. However on pressing the accelerator more, the jerks are not felt.
The first gear feels a bit abnormal when driving in high traffic, vibrations are higher and the engine rpm also drops below idle.
The car drives good at higher speeds (>30 KPH) and its difficult to tell if anything is wrong with the AT box.
2 weeks back, I took the car for a 100 Km drive. Couple of times in the middle, it got stuck to 4th gear (which I checked by putting the shifter to manual mode), it didn't shift up or down in manual mode as well. I had to shut off the engine and restart, and it was back in first gear. This happened 3-4 times.
Few days back, I again took it to drive. On Mumbai expressway, it got stuck to 4th gear and this time on restarting, it didn't come back to first. I had to get it towed since I had to reach somewhere on time. I later realized I shouldn't have driven the car on the expressway with these kind of issues for safety reasons. Now, it doesn't move forward at all, just goes into reverse, and surprisingly now the jerks of the reverse are gone.
I am keen to get the AT box replaced from a donor vehicle, but I also suspect that there could be issues outside the gearbox (TCM, ECM, wiring, etc.). The worst would be if I get it changed and the problem persists.
What do you guys think could be the problem here? I do not trust the ASC, don't know how they would help. Would also be of great help if anyone can give any leads of a used gearbox. Thanks in advance!
Links of youtube videos-
How to clean solenoids?
How to remove solenoids?