M/T gear oil

[xgmad]

Im thinking of getting a replacement jetta after the crash, a used M/T 2.5 5 cylinder.

Whats a good thick gear oil for really smooth shifts?

My temperatures never go down to 60 degrees Fahrenheit in the wintertime.

My first choice is penzoil syncromesh.

 

[haggler]

I used Redline in my ND miata and it was better in every way over the OEM. Highly recommend it.

 

[HyundaiAbuser]

Im thinking of getting a replacement jetta after the crash, a used M/T 2.5 5 cylinder.

Whats a good thick gear oil for really smooth shifts?

My temperatures never go down to 60 degrees Fahrenheit in the wintertime.

My first choice is penzoil syncromesh.

I’m not sure if thick gear oil and synchromesh go in the same sentence. Smooth shifts are brought by good synchro engagement which is specifically what synchromesh is known for so that’s probably what would give you what you want. You should also consider the mt85 or mt90 redline series if you want a thicker fluid that has the same additives for synchro engagement.

 

[930.engineering]

Very good point.
75W-90 is way too thick for this VW MQ250 gearbox factory filled with a 75W. It's more than twice as thick anything above freezing and will cause shift issues, even in a milder environment.
I found Castrol Syntrans V FE 75W-80 = Castrol TRANSMAX Manual V 75W-80 felt best in my MQ350 transmission. V = Volkswagen. Shifting is nothing less than excellent. Some report that Ravenol MTF-2 75W-80 also works great in VW applications, though I only tried this in my own Mini's Getrag gearbox so far.
Whether you go for Castrol or something different - make sure to use GL-4 or GL-4+ only.

 

[benjy]

my 2001 jetta O2J 5 spd + O6M 6 spd in my Audi TT manuals both get Redline MT90 for great shifting. i live in PA + winters get cold + shifting is always good! expensive but worth it as little is needed + it lasts longer, its a REAL synthetic!!

 

[Wylie6G72]

Redline MT-90 has improved every difficult transmission I've used it in.

 

[kebabaluba]

Redline MTL are my choice, i had that oil in 3 different cars with great results and improved shifting.

 

[xgmad]

make sure to use GL-4 or GL-4+ only.

Whats the difference between GL-4+?

I've only used 20w50 or sae 40 motor oil in manual transmissions.

 

[slacktide_bitog]

Valvoline or Pennzoil Synchromesh

 

[kebabaluba]

Whats the difference between GL-4+?

I've only used 20w50 or sae 40 motor oil in manual transmissions.

You shouldnt use motor oil in transmissions unless the manufacturer approve this. Dedicated transmission oils have additives that is suited for transmissions.

 

[MolaKule]

Whats the difference between GL-4+?

I've only used 20w50 or sae 40 motor oil in manual transmissions.

There is no such thing as an API GL-4+ rating.

I suggest you use a dedicated MTF with a viscosity close to the manf.'s OEM 100C viscosity.

 

[kebabaluba]

There is no such thing as an API GL-4+ rating.

I suggest you use a dedicated MTF with a viscosity close to the manf.'s OEM 100C viscosity.

Actually Castrol offer gear oil in GL-4+ spec, but it seems that oil just meet more manufacturer specific approval.
https://www.castrol.com/en_gb/unite...ids.html#tab_transmax-manual-transaxle-75w-90

 

[MolaKule]

Actually Castrol offer gear oil in GL-4+ spec, but it seems that oil just meet more manufacturer specific approval.
https://www.castrol.com/en_gb/unite...ids.html#tab_transmax-manual-transaxle-75w-90

The latest API chart I have does not have any specification for GL-4+. Do you have a later API chart that gives the definition for a GL-4+ protection rating? I suspect this is marketing taking liberties with the API specs.

 

[UG_Passat]

Im thinking of getting a replacement jetta after the crash, a used M/T 2.5 5 cylinder.

Whats a good thick gear oil for really smooth shifts?

My temperatures never go down to 60 degrees Fahrenheit in the wintertime.

My first choice is penzoil syncromesh.

Technically, it uses a lighter weight 75W gear oil, which Redline has recently introduced to its lineup for the Germans that want to maximize fuel economy in the gearbox.

But, I have used Amsoil MTG in my old 02J without issues, and Redline MT-90 in my old Camry V6 5-speed manual without issues.

 

[kebabaluba]

The latest API chart I have does not have any specification for GL-4+. Do you have a later API chart that gives the definition for a GL-4+ protection rating? I suspect this is marketing taking liberties with the API specs.

Its not official API rating but rather something Castrol do to meet manufactrurer specifications/standards, maybe other oil brands do the same.

 

[930.engineering]

Agree, some manufacturers use "GL-4+" just to claim their product provides higher wear protection levels than other brand's plain GL-4, but it's still not GL-5.

my 2001 jetta O2J 5 spd + O6M 6 spd in my Audi TT manuals both get Redline MT90 for great shifting. i live in PA + winters get cold + shifting is always good! expensive but worth it as little is needed + it lasts longer, its a REAL synthetic!!

Redline isn't the only true synthetic on earth. Castrol Syntrans V FE 75W-80/Transmax Manual V 75W-80 is majority PAO.
That said, using the word "always" is often difficult. Does your gearbox actually shift "good" starting at -30°F or you just didn't experience this temperature yet?

Redline MT-90 has improved every difficult transmission I've used it in.

Honestly, I don't want to deny your experience, but I have a hard time to believe, since I actually made very different experiences with similarly twice as thick as OE transmission oils, especially on a somewhat colder morning. Unreasonably thicker gear oil doesn't even help when it's hot, it just doesn't make any sense at all in very most applications (in particular in VW transmissions), just as almost always when overdoing things. Viscosity needs to be appropriate, not as high/thick as possible.

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