Hi all 

 

sometime while driving my Octavia ambiente 1.6  2003 automatic gearbox suddenly RPM go up and seems that shift down one gear , also when stop after long driving and need to move again it seems that it not shifting up gear for few minutes and stuck on gear 1 then start to shift gears up normally , i went to workshop and after fault test there was crank speed sensor malfunction , i replaced it but this did not solve the problem 

 

any tips or help for this problem please ? 

 

Have you checked the gearbox oil level yet?.

 

no i did not and also in workshop did not check and did not mention this at all , but if  there problem in oil level or temperature should appear in faults records , correct ? 

anyway can i do it myself and how , or i need to do it in workshop ?

 

@Leopard You don't state the mileage, but if it's over 50_000 miles (80_000 km) it might be worth changing the gearbox oil, as per ZF Transmissions' recommendation (and yes I know VAG don't suggest this).

It is difficult to give accurate info without the three letter engine code for your engine, but to give you a rough idea, this is for a 1.6 - http://workshop-manuals.com/skoda/octavia-mk1/power_transmission/automatic_gearbox_01m/automatic_gearbox_control_assembly_housing/inspect_atf_level_if_necessary_top_up/change_atf_or_top_up_after_repair/

On 6/12/2017 at 00:02, Leopard said:

I went to workshop and there was small oil leakage from oil cooler , they fix the leakage and replace gearbox oil and also filter , i hope this will solve the problem i need to test it to be sure  because i face this issue only when continuous driving more than 100 km  

 

@Leopard Well, a leak and the resultant low fluid level would explain your reported symptoms. Hopefully the new fluid will also give you a smoother (and possibly more economical) driving car too.

the problem seems not solved , i have leak again at the same place , i am not sure that it is from oil cooler because already replace the 2 o-ring under it  , is there any another possible leak that make oil accumulated on the top of gearbox  around the oil cooler ? 

 

 

Is the oil cooler itself leaking rather than the o rings?, dies it show signs of oil around the cooling vanes?

@Leopard - As @kentphil1 says, I'd suspect the oil cooler itself so look closely for oiliness on the matrix and end tanks. Remember that you have access to the car and we have to rely on what you tell us.

The first time the mechanical suspect that the leak from o-ring so he replaced it but after that i drive the car in the city for 3 days without any problems and no sign of leak but when i traveled to another city about 180 km i have same issue with gears shifting i stoped the car and look under it and found oil , so i went to mechanical again and he test the oil cooler and check for leak and he told me that the oil is comming out from vent on top of gear box , i need to know if this correct becouse i do not trust mechanical any more  and what cause oil to come out from vent , is it overheated becouse seems to happen only on long drive 

@Leopard - I don't have my Octy manual with me, but it's quite usual to have a thermostat to control an oil cooler in order to get the oil up to full operating temperature faster. If the oil in the transmission overheats because that thermostat is stuck closed then yes you could well get oil blowing out the vent.

 

Now I only really worked this out when you told me about oil coming out of the transmission vent on a long run in a relatively hot country.

I try to look in gear box manual but i could not find any thing about thermostat for gearbox oil thermostat , can you provid me where i can find it ?

 

 

 

When the oil leaks out of the vent, after it has cooled, if you put a little bit on your finger and gently sniff it, does it smell like just transmission fluid, or do you smell axle oil mixed in with it?.

 

If it is the second, you may have a secondary shaft seal failing in the box, and pressuring oil out of the box vent.

@kentphil1 it smells like transmission oil , the mechanic told me that it mybe problem with cooling system couse oil not cooled enough and overheated so it come out from vent but this seems not right becouse the engine cooling water temperature stay normal and he check the transmition control for any fualt recorded and  no gearbx  high temperature , so what is causing the oil to come out from vent and as i mentioned befor it happened only with long drive 

@Leopard - The transmission oil is separated from the engine oil and the engine water jacket. Also, after a bit of playing around on the RossTech (makers of VCDS) site, and presuming you have a 01M automatic transmission, there is no way of measuring the transmission oil temperature other than putting a suitable thermometer into the filler or vent holes, except relying on the knowledge that hot oil expands and sometimes gasses, which honestly does explain it coming out of the vent hole.

 

However, https://en.wikipedia.org/wiki/Volkswagen_01M_transmission indicates that the transmission has an oil-water heat exchanger rather than a simple oil cooler (radiator). This could mean that the oil and water are overheating but it's not showing on the instrument panel because, by design, the water temperature gauge reads 90C whenever the water thermostat senses a temperature between 70C and 110C.

 

So an apparently off-the-wall but actually important question, are you running a 33% to 50% G12(+(+)) to 67% to 50% water mixture as coolant?

@KenONeill actually the coolant now is only water , should i add any addition to water in summer ? i know that in winter we should add anti-freeze 

@KenONeill@kentphil1 sorry but this is my first car and maybe need helps in basics so thank you in advance to be patient with me

 

@Leopard - The cited G12 specification isn't just "antifreeze"; it also contains corrosion inhibitors which protect the engine water jacket, and acts as a "water wetter" (which sounds odd, and will probably sound even odder if you auto-translate it) and basically increases the heat transfer rates into the water jacket, and out of it through the radiator.

 

Buy 2 litres of the latest iteration of the G12 "OAT" specification which will be pink or orange (do not buy a blue "ethylene glycol antifreeze), and on a cold engine drain off 2l of coolant (don't worry too much about draining a bit more than 2l; you can top off with water afterwards) then add the G12.

@KenONeill ok i will do it as soon as possible , but do you think this will solve the issue what I am facing and will prevent oil from overheating and coming out from vent , or there anything else i should check and maybe it is another possible reason for this ?

  

@Leopard - I can't promise anything, but it will increase the ability of the cooling system to remove heat from the engine and gearbox.

I'm with Ken on this, in that it appears that you are building fluid pressure due to under cooling under load. change your coolant to the correct spec for your climate as the coolant raises the boiling point together with the pressure that the system runs at. If you still experience issues, I would get your transmission cooler checked for internal blockages in some of the cooling tubes. I would also check to see if VAG recommend any extra cooling components for operating in your hot climate for long journeys or high loads.

On June 23, 2017 at 18:00, kentphil1 said:

I'm with Ken on this, in that it appears that you are building fluid pressure due to under cooling under load. change your coolant to the correct spec for your climate as the coolant raises the boiling point together with the pressure that the system runs at. If you still experience issues, I would get your transmission cooler checked for internal blockages in some of the cooling tubes. I would also check to see if VAG recommend any extra cooling components for operating in your hot climate for long journeys or high loads.

Hi all i added the correct coolant but no improvment still have oil overflow from vent , i am waiting to recive elm327 obd2 adapter so i will see if it is possible to monitor gearbox temerature in real time , then i will go to workshop for oil cooler check , i search the web for possibel causes and all was overheating but from different reasons , i am afraid that i have internal problem inside the gear box and i do not have to open it since i do not think we have quilified mechanical hear 

@kentphil1 @KenONeill

Hi all i added the correct coolant but no improvment still have oil overflow from vent , i am waiting to recive elm327 obd2 adapter so i will see if it is possible to monitor gearbox temerature in real time , then i will go to workshop for oil cooler check , i search the web for possibel causes and all was overheating but from different reasons , i am afraid that i have internal problem inside the gear box and i do not have to open it since i do not think we have quilified mechanical hear