Should i go for even thinner fluid ?

[NICAT]

Hi.
Winter is coming...

And car's gearbox isn't happy about it.

I used to have hard downshifting problem with manual transmission. There is no Dedicated MTL / STF in my country. With recommendations of some friends here, i decided to use Motul 75-90 GL4/GL5 Fully Synthetic transmission fluid. It really helped a lot. Never had with issue after using Motul.

But since it is getting colder here, in the mornings, it grinds when i try to shift to 2nd gear. Once gearbox is warms up fully, it becomes Ok.
If this won't damage the transmission, its ok for me too. But, since the issue seems to be related to oil viscosity, Would you recommend to go for Ravenol 75-80? (Or 75-85) Would it cause any problem at hot summers ?
It is OPEL's F16 Gearbox.

 

[MrMoody]

Are you sure your clutch is releasing fully?

 

[NICAT]

Originally Posted by MrMoody
Are you sure your clutch is releasing fully?


Yes Sir. Still will have it checked, but the it shifts fine when it gets warmed up. Does this mean problem is not related to clutch?
Do you think it would worth trying thinner oil ?

 

[WyrTwister]

Is the transmission oil level correct ?

How hot does it get in your country ? How cold ?

 

[MrMoody]

I don't know enough about that transmission to tell you about fluid, but I do know a dragging clutch can behave exactly as you are describing. As it heats up, the parts/hydraulic fluid expand just enough to stop the dragging.

 

[SwampSurvivor]

Is it a 4x4 vehicle? If so - let it run for a few minutes in 3rd gear (or any gear) with the transfer case in neutral.

I have an extremely cold blooded ford ZF-5 running ATF and that's the only way to get it to shift in the cold.

 

[147_Grain]

Try double clutching when shifting to second gear to see if the clutch isn't synchronizing properly.

 

[NICAT]

Have done a verification test just now for clutch drag.
Lifted front wheel, Shifted to Neutral, Started the engine, Tire is spinning.
Shifted to First gear, Tire is spinning, Pressed the clutch pedal, Tire stopped spinning very fast. Tested several times,
Shifted to neutral again, gearbox warmed up, and tire is no more spinning in neutral.

By the way, it is a little off topic, May be this is another issue. I have difficulty to shift reverse gear. It simply doesn't shift till i slowly release clutch pedal, while forcing to shift Reverse.

 

[maxdustington]

Originally Posted by NICAT
By the way, it is a little off topic, May be this is another issue. I have difficulty to shift reverse gear. It simply doesn't shift till i slowly release clutch pedal, while forcing to shift Reverse.
You know the old trick of shifting into second before shifting into reverse? First and reverse are usually not synchronized so shifting into a synchronized gear beforehand usually helps.

My old Golf had problems getting into second on really cold days even with fresh fluid although I put Delo dino into it (pre-BITOG, I would spring for Redline now). Sounds like your second gear synchro is worn.

 

[69GTX]

Most manual transmissions probably behave this way....at least the performance Chevys and Pontiacs I've played with do (Vettes, Firebirds, Camaro's, etc.). There's probably not one perfect fluid that can handle both the low and high end of temp range for optimum performance and protection. ATF was selected as OEM fluid in many cars just because it flows the best at low temps and gives modest anti-wear protection. Double clutching will help get you into 2nd gear the first time. I do that on my ATF specced 1999 M6 Camaro SS. Below 45-50 degrees ambient or so it's still notchy and not warm enough for that first 1-2 shift. MTF only makes it harder. After 3-5 minutes of driving (1-2 miles) it's no longer an issue, even at 30 deg F ambient. And just because it "feels" like a shift has gotten "smoother" with a different fluid (usually thicker or synthetic) doesn't automatically mean your transmission is receiving less wear and tear....especially the synchros.

 

[NICAT]

Originally Posted by 69GTX
Most manual transmissions probably behave this way....at least the performance Chevys and Pontiacs I've played with do (Vettes, Firebirds, Camaro's, etc.). There's probably not one perfect fluid that can handle both the low and high end of temp range for optimum performance and protection. ATF was selected as OEM fluid in many cars just because it flows the best at low temps and gives modest anti-wear protection. Double clutching will help get you into 2nd gear the first time. I do that on my ATF specced 1999 M6 Camaro SS. Below 45-50 degrees ambient or so it's still notchy and not warm enough for that first 1-2 shift. MTF only makes it harder. After 3-5 minutes of driving (1-2 miles) it's no longer an issue, even at 30 deg F ambient. And just because it "feels" like a shift has gotten "smoother" with a different fluid (usually thicker or synthetic) doesn't automatically mean your transmission is receiving less wear and tear....especially the synchros.


You mean ATF for Manual Transmission ?
Doesn't it damage brass synchronizers ?

 

[mk378]

What does the manufacturer specify?

It is really rare to have 75W gear oil in a modern car MT. ATF is used in many manuals. The 1990's Hondas said to use 10w40 motor oil (which is what is in mine) or Honda MTF.

 

[Ded Mazai]

There is nothing wrong to try a thinner oil like 75W-80 or 75W-85. The gear wear may increase but the shifting will improve. The rule of thumb here is to use the thickest oil which allows you to drive the car comfortably in the winter.

 

[69GTX]

Originally Posted by NICAT
Originally Posted by 69GTX
Most manual transmissions probably behave this way....at least the performance Chevys and Pontiacs I've played with do (Vettes, Firebirds, Camaro's, etc.). There's probably not one perfect fluid that can handle both the low and high end of temp range for optimum performance and protection. ATF was selected as OEM fluid in many cars just because it flows the best at low temps and gives modest anti-wear protection. Double clutching will help get you into 2nd gear the first time. I do that on my ATF specced 1999 M6 Camaro SS. Below 45-50 degrees ambient or so it's still notchy and not warm enough for that first 1-2 shift. MTF only makes it harder. After 3-5 minutes of driving (1-2 miles) it's no longer an issue, even at 30 deg F ambient. And just because it "feels" like a shift has gotten "smoother" with a different fluid (usually thicker or synthetic) doesn't automatically mean your transmission is receiving less wear and tear....especially the synchros.


You mean ATF for Manual Transmission ?
Doesn't it damage brass synchronizers ?


ATF is used in most GM manual transmissions, including the Vettes. Though in recent years they may have gone to something else. ATF was the choice because of owners complaining about poor low temperature shifting. ATF works well on carbon/kevlar synchronizer friction rings (blockers)....even the earlier cellulose lined ones. I doubt it hurts brass but probably lacks the viscosity the brass may need for longevity. You can generally run a lot stouter fluid (like MT fluids) with brass as there's less negative interactions with the metal than various man-made compounds.

 

[CR94]

Somewhat similarly ... My Mazda specified Type F ATF for the transmission. At about 360,000 miles, I had a transmission shop replace internal bearings that had become very noisy. Instead of Type F, the shop used an allegedly synthetic manual transmission oil which they couldn't or wouldn't identify when asked. After that repair, the bearings were quieter than when new, oil persistently spurted out of the breather opening, AND shifting into 2nd gear was difficult at first in cold weather. No further problems with the transmission in the next 246,000 miles. Synchronizer material was unknown.

 

[DONWATERS]

I use 10w30 mobil 1 in my Jeeps transmissions and its my favorite. Good in cold and hot.

 

[Linctex]

I use 0W-20 Mobil 1 in my Tremec 3550 transmission

 

[NICAT]

Hi.
I used Ravenol 75w80 MTF.
Now there is no grinding noise in the cold morning. And it shifts very smoohtly. There is no noise in gearbox due to thinner fluid.
Thanks all for your support.

 

[nthach]

For manuals, I use Red Line MTL. Honda was an odd-ball calling for 10W-30 motor oil until API SM/SN became a thing. I recalling using Dex III/Mercon for a Ford/Mazda M5OD.

It's best to use a GL-4 spec fluid to keep the yellow metals happy.