1st gear is very obstinate

[Ryo]

Hi,As for my car, 1st gear is very obstinate in the morning.
It is the obstinate that a shift does not seem to fall out.
Is there a similar case?

Please teach the person knowing a solution by all means !!

06 megane dci od=9000km

[Deano16v]

is it always when the car has been left for a while? most renault gearboxes are reluctant to go into gear when they are first started after being left overnight etc. the gearbox oil is very thick and takes a bit of warming up before the box gets smoother

[Ryo]

I see. thank you dor your reply.
The symptom that 1st gear does not fall out always. But it is very frequent.
I changed it for slightly smooth oil(Motul) in last month, but it is not improved.

[AlexB]

It's the synchroniser of the first gear, which according to Webcode does not exist. Some time ago I switched to a fully synthetic ester based GL4+GL5 transmission oil, which significantly improved gear change. This oil, however, is 75w-90 instead of 75w-80, and it takes longer to warm up in winter.

What Motul are you using now?

[Ryo]

I see.This is an act of the 1st synchronized mechanism.

I thought that ND0-M/T did not equip the synchronized mechanism on 1st . Because I cannot insert my gearbox in 1st gear even at very low speed(5km/h).
The temperature of my town is 7degrees Celsius now, but a shift is very firm.

I changed it for this oil last month.
https://blog.livedoor.jp/dci110bayern/ar ... #comments/

I think that it is the 75w-90 oil that you say.
By the way, I paid 500 euros...

[AlexB]

Ryo,

Motul Motylgear 75W-90 is a semisynthetic oil similar to the factory Elf Tranself TRJ 75W-80, but its viscosity at 40 deg C is 66 mm2/s as opposed to 47 mm2/s of Elf. So, expect more difficult gear change when cold, the same feel when warm and ability to tolerate higher loads.

For improved gear change it was recommended to use a fully synthetic oil. These posts could have disappeared when our database crashed.

Regarding synchronisers or their absence. If there were no synchronisers, then a nasty sound would be heard in an attempt to switch gears on the move. A synchroniser normally delays the engagement until the the speeds are equalised. Speed equalisation is caused by friction in the synchroniser, hence it is affected by oil.

[Ryo]

Alex,Thank you for your reply.
I made a mistake in selection of oil.
The oil which a workshop recommended to me was not suitable.

I intended to have chosen the smoother oil, but rather chose the oil which was hard to move!!

I cannot insert my gearbox in a 1st gear since I bought a car, but do you think that you are caused by oil?
My 1.9dci does not come in a downshift to 1gear unless I completely stop.
So I have tried downshift into 1st by double declutching.
non!!A mystery!!
Best Regards,Ryo

[AlexB]

It is not as simple, Ryo. Only similar oils can be compared by their viscosity.

For example, Tranself TRJ, 40 deg C viscosity 47, is used in Megane; and Tranself TRX, viscosity 51, is used in vans with the same (needs to be checked) gearbox. Your oil, being of approximately the same quality (which I am not sure about), is even thicker -- 66mm2/s.

Fully synthetic oils solidify at lower temperatures than semi-synthetic and at around 0 degC may be thinner. In town driving your gearbox never gets too hot, so the low temperature viscosity is important. Add to this completely different lubricity characteristics of synthetics and different packages of additives used... It is hard to guess which oil to use, unless someone have tried it.

[Ryo]

I see. It is precise, and your indication is useful for we Japanese(A car-culture developing countries) very much. Thank you.
I have various viewpoints about the oil.

He said that an additive is effective as　a solution a　the problems　when a problem is not improved.

Thanks, It'll try something!

[AlexB]

Ryo,

Please be careful with additives. Each oil already contains a very precisely formulated combination of additives. Oils of different types and brands have different additive packages, whose content is kept secret. Therefore, it is virtually impossible to guess what supplement to add in order to improve something in your particular application. The companies who sell additives to public never disclose the content of their bottles and never give a statement that their product improves some particular characteristic of some particular oil, e.g. Motul Motylgear 75W-90. So, those who are using these products are essentially trying to achieve a particular result by combining unknown formulas at random...

In this forum and at Parkers some people commented on the use of synthetic gear oils. It would be good to find this information. Then ask the experts, such as Oilman, to comment on it. Read technical documents in his web site ( https://www.opieoils.co.uk ). It makes sense to start another thread asking everyone who are using a non-standard gear oil to share their experience.

[Ryo]

I respect for your judgment utterly.
We did not have the knowledge that you had.
When some problem occurs in Japan,they depend on an additive immediately.

It is a very dangerous thing.It was a reverse act again.

I will judge it to see the condition of the transmission for a while.
Because drive only 9,000km.

[AlexB]

This is because people are buying cheap unbranded oils without checking their datasheets. Triple QX 75W90 Semi Synthetic Gear Oil is completely unsuitable for this applications, because these gearboxes require a thinnest oil within 75w range (see SAE definitions). Most 75w90 oils are 3 times as thick when cold and become even worse under freezing temperatures. Cheap 75w80 oils are slightly better in this sense, but most are still unsuitable. See my post above for an example of what actually works.