u/marwan_alshanf1

Hello there, I want to thank everyone who would be reading this post and for their time in replying.

I'm seeking your feedback / opinion on my Daihatsu Terios 2010 - 7 seater rear wheel drive 4 speeds automatic, Engine: 3SZ, 1495 cc (1.5L)

In the past 2 weeks my car has been having rough reverse, and lag when descending from the 4th gear to the 3rd gear while going forward at 80.mph

-Reverse Problem: Car would completely not go backwards when on (R), something it would go but very very slowly and sometimes it would reverse normally and sometimes it won't go backwards at all, when pressing the gas it would make knocking sounds from the transmission and struggle hard to actually move backwards and it won't even move normally it would be slower than normal and the engine would get louder trying to reverse the car.

The noise it makes when reversing only occurs on (R), when pressing the gas it's like the car is resisting to go backwards and then when it does, it's like a very very hard gear shift with a knock and shake. (Nosies won't come unless i press the gas paddle on (R) the harder i press the louder it gets and the more it shakes and knocks, car wouldn't move backwards if i didn't press on the gas paddle).

-Going Forward: the car would struggle to descend from 4th gear to 3rd gear (sometimes), it's like it will shit to 3rd gear but get stuck on a high rpm for a few seconds until it goes to 2nd gear as i am slowing down, and overall it seems that the car is accelerating in a much more slower rate then normal.

Then while i was driving ones the car seemed to stop accelerating while going past 40, so i stopped the car for a few minutes and placed it on (P) then moved again to (D) and it was back to normal, two days later while driving the car same thing happened but this time it wouldn't go forward at all or it was going forward very very slowly, was barley able to take it to a mechanic, he then recommended a special transmission oil that he said might help with my car problems, after adding it.. the car moved forward for a couple of minutes and then stopped moving completely, it wouldn't go forward or backwards the slightest, he then opened the gearbox to check on things that's when he found a lot of dirt and mud/sand inside the gearbox, he cleaned the area and closed it back, adding new gear oil and the car worked again with the same previous symptoms except now it moves forward normally, i drove it like that for about a weak until two days ago where it stopped going forward and backwards at all again.

Notes:

1. a video will be attached of what the gearbox looked like when he opened it to clean it.
2. The mechanic is only a mechanic by experience and he's not a fully qualified mechanic he has never studied car mechanics, All the mechanics in the country I'm staying at is like that.
3. Throughout this whole ordeal the reverse problem was always there and never went away.

The mechanics that I have spoken to and The car dealership said that I have to replace the entire transmission system because all of them are incapable of fixing complicated stuff inside the transmission.

Experienced car mechanics please tell me what do you think the issue is and whether or not should I actually replace the transmission I'm not sure what the problem is, is it the clutches or is it the solenoids/sensors.

Why would the car move forward normally again after the gearbox cleaning but then stop again after a week?

If i will replace the transmission what signs should i be looking for in a used transmission to make sure i am not getting scammed and buying a worn out transmission?

Feel free to ask any questions regarding the car.

Hello there, I want to thank everyone who would be reading this post and for their time in replying.

I'm seeking your feedback / opinion on my Daihatsu Terios 2010 - 7 seater rear wheel drive 4 speeds automatic, Engine: 3SZ, 1495 cc (1.5L)

In the past 2 weeks my car has been having rough reverse, and lag when descending from the 4th gear to the 3rd gear while going forward at 80.mph

-Reverse Problem: Car would completely not go backwards when on (R), something it would go but very very slowly and sometimes it would reverse normally and sometimes it won't go backwards at all, when pressing the gas it would make knocking sounds from the transmission and struggle hard to actually move backwards and it won't even move normally it would be slower than normal and the engine would get louder trying to reverse the car.

The noise it makes when reversing only occurs on (R), when pressing the gas it's like the car is resisting to go backwards and then when it does, it's like a very very hard gear shift with a knock and shake. (Nosies won't come unless i press the gas paddle on (R) the harder i press the louder it gets and the more it shakes and knocks, car wouldn't move backwards if i didn't press on the gas paddle).

-Going Forward: the car would struggle to descend from 4th gear to 3rd gear (sometimes), it's like it will shit to 3rd gear but get stuck on a high rpm for a few seconds until it goes to 2nd gear as i am slowing down, and overall it seems that the car is accelerating in a much more slower rate then normal.

Then while i was driving ones the car seemed to stop accelerating while going past 40, so i stopped the car for a few minutes and placed it on (P) then moved again to (D) and it was back to normal, two days later while driving the car same thing happened but this time it wouldn't go forward at all or it was going forward very very slowly, was barley able to take it to a mechanic, he then recommended a special transmission oil that he said might help with my car problems, after adding it.. the car moved forward for a couple of minutes and then stopped moving completely, it wouldn't go forward or backwards the slightest, he then opened the gearbox to check on things that's when he found a lot of dirt and mud/sand inside the gearbox, he cleaned the area and closed it back, adding new gear oil and the car worked again with the same previous symptoms except now it moves forward normally, i drove it like that for about a weak until two days ago where it stopped going forward and backwards at all again.

Notes:

1. a video will be attached of what the gearbox looked like when he opened it to clean it.
2. The mechanic is only a mechanic by experience and he's not a fully qualified mechanic he has never studied car mechanics, All the mechanics in the country I'm staying at is like that.
3. Throughout this whole ordeal the reverse problem was always there and never went away.

The mechanics that I have spoken to and The car dealership said that I have to replace the entire transmission system because all of them are incapable of fixing complicated stuff inside the transmission.

Experienced car mechanics please tell me what do you think the issue is and whether or not should I actually replace the transmission I'm not sure what the problem is, is it the clutches or is it the solenoids/sensors.

Why would the car move forward normally again after the gearbox cleaning but then stop again after a week?

If i will replace the transmission what signs should i be looking for in a used transmission to make sure i am not getting scammed and buying a worn out transmission?

Feel free to ask any questions regarding the car.

>!UPDATE: i tried to see if the car would drive again and this is what happened

Upon turning on the car, a wheezing/hissing noise would come from the gearbox/transmission, it's not very loud and it's not low either, after a couple of minutes the noise will start to die down but eventually it will still be there but very faint tho much quieter from when first turned on

The car would drive for a few minutes after starting it on first gear before completely stopping again, the car doesn't want to shift past the first gear or stay on it for more then a few minutes then it would very slowly slow down until it reaches complete stop and stops moving or shifting again, i tried 3 times to turn it on and off each with 15 break in between and it's seems whenever the car is cold as soon as i turn it on it would drive for a few minutes and then stop, it won't shit gears and go at (20~30 speed max).!<