Volkswagen 020 5 speed trans- help, my head hurts!

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Hi all, this is an amazing forum and I've learned alot in the process of selecting new manual transmission fluid for my car. I need some help selecting the right MTF for my application. I own a 1984 Volkswagen Rabbit Gti with 52k original miles with the factory close ratio 5 speed manual (model 4k 020). It shifted great with no grinds into 2nd gear which is a common thing on these older 020's. The trans is out for new external seals and I am ready to refill fluids. My original owners manual says the correct manual trans spec oil is: Hypoid-oil SAE 80, SAE 75W/80 or SAE 80W/90 (Mil-L-2105 or API/GL 4).

I have read in great detail several posts about cSt ratings and it appears that any of the category "C-E Synchromesh MT fluids" MolaKule posted should work fine but since my car and owners manual is coming up on 40 years old I want to make a good choice. A German transmission rebuilder told me they only spec BG Sycro Shift II for the VW 020 but it is very expensive, on the lower end of the cSt rating (and therefore thinner?) and not readily available locally. I read lots of positive reviews here on GM/Delco, Valvoline and Pennzoil Syncromesh but noticed that they are higher on the cSt rating than BG and I'm not clear if they spec to or "meet" GL-4 rating or for that matter if they meet the range of SAE 75, 80W/90. GM seems to have several different types of Syncromesh so not sure which is correct. Lastly, it's possible my trans has an aftermarket Quaife ATB LSD in it but I was not able to confirm it visually so ideally I'd like an oil without LSD friction modifiers just in case. Quaife says they like a whatever the manufacturer recommends.

Can you all help with a confirmation of which might be best for a performance application, safe for the brass synchros, and minimizes potential for future 2nd gear grinds? 30 years ago I did this on another Rabbit Gti and I recall simply getting a no-name dino pretty thick gear oil which worked fine! Much seems to have changes since then! I appreciate any guidance you can give me based on the parameters I am listing and let me know if I missed anything important.
 
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Welcome to BITOG 🎉

If you're in the US, you might like Liqui Moly #20012
If you like Redline, see that they suggest for your GTI :)


That seems to be available in Canada, but not the US :sneaky:
 
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What about this one?

nope, not available anywhere in the US that I can find :alien:

Last I saw it available anywhere was an ebay seller that claimed to be some racing team that was selling off the excess from a case they didn't need, and another from evolubesupply, but that supply has dried up, too

It's almost impossible to find 75w90 GL4 suitable for manual transmissions in the US
 
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Don't use Redline in a VW 020 the crap (it really is in these) will make it shift terrible. The Pentosin MTF2 works great in these regardless of temp, you can also us BMW MTF-LT-2 which is close or maybe even the same product. Both are GL4 which is required for this unit.


 

1983Gti

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Thanks for the replies so far. Also I am in USA Northern California inland SF Bay Area. Temps when I drive my car will be April-October with summer highs around 95 degrees F and lows of 45f. Most actual driving will likely be in the mid 60's-80'sF.

As Trav suggested with Redline I have heard several complaints about for these gearboxes enough that people switch it out (regardless of which RL version). The Pentosin or BMW suggestion may work out as they would fall close to the BG but in section B @MolaKule 's chart; might be a bit thin for this application in spite of the GL-4 designation? Is there a reason I should stay away from the Valvoline, Pennzoil or GM Syncromesh MTF's? Do they have added friction modifiers which are a no-go for a Quaife ATB LSD? They fall in the middle range of the cSt chart.

It's odd to me that on paper the Pentosin/BMW recommendations are in the lower Viscosity range section B= 7.0 to 7.6 [email protected] while the LiquiMoly and Motul are near the other extreme end in section G. 14-15 cSt. Can someone explain to me how something very thin and something else very thick would be OK for my application? Are they just not that different in reality?
 
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MolaKule

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...Is there a reason I should stay away from the Valvoline, Pennzoil or GM Syncromesh MTF's for my application? Do they have added friction modifiers which are a no-go for a Quaife ATB LSD?
They (Valvoline, Pennzoil or GM Syncromesh) simply have a slightly higher viscosity (~ 9.5 [email protected]) than the 7.7 cSt of the Pentosin MTF-2, but all have the proper friction modification for synchro assemblies. Sometimes, worn transmissions can benefit from a higher viscosity MTF.

What is the viscosity of the OEM fluid??
 

1983Gti

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They (Valvoline, Pennzoil or GM Syncromesh) simply have a slightly higher viscosity (~ 9.5 [email protected]) than the 7.7 cSt of the Pentosin MTF-2, but all have the proper friction modification for synchro assemblies. Sometimes, worn transmissions can benefit from a higher viscosity MTF.

What is the viscosity of the OEM fluid??
Hi @MolaKule ! I am not sure what the factory actual trans fluid is or exactly what was in the box (I suspect it was the original fluid). The factory owner's manual in my glovebox states to use: Hypoid-oil SAE 80, SAE 75W/80 or SAE 80W/90 (Mil-L-2105 or API/GL 4). The car has 52K original miles and the trans had zero issues (no second gear crunch when cold or with quicker shifting etc.) and looks clean inside. It may have a Quaife ATB LSD in the trans. It will mostly be a spirited weekend driver. It has a Callaway Turbocharger installed but I'm old and won't be abusing it.

It's odd to me that on paper the Pentosin/BMW recommendations above are in the lower Viscosity range section B= 7.0 to 7.6 [email protected] while the LiquiMoly and Motul are near the other extreme end in section G. 14-15 cSt. How can something very thin and something else very thick would be OK for the same application? It seems like a very wide range; are they just not that different in reality?

I am in USA Northern California inland SF Bay Area. Temps when I drive my car will be April-October with summer highs around 95 degrees F and lows of 45f. Most actual driving will be in the mid 60's-80'sF.
Thanks!
gti020trans.jpg
 
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MolaKule

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It's odd to me that on paper the Pentosin/BMW recommendations above are in the lower Viscosity range section B= 7.0 to 7.6 [email protected] while the LiquiMoly and Motul are near the other extreme end in section G. 14-15 cSt. How can something very thin and something else very thick would be OK for my application? Are they just not that different in reality? I am in USA Northern California inland SF Bay Area. Temps when I drive my car will be April-October with summer highs around 95 degrees F and lows of 45f. Most actual driving will likely be in the mid 60's-80'sF.
Thanks!
I don't see how they could, especially in cold weather.

Yep, a 7.0cSt thicker fluid can make a big difference in shift quality.
 

1983Gti

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Given the manual recommendation (why the wide factory range and how to pick one?) and the temperature range I will be driving, which letter class should I be focused on? C, D & E?
 
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I have an 87 Cabriolet and the transmission has a snap ring that broke and locked up the tranny. This was at 124k. I put a Golf transmission in it that is a 5 speed. I replaced the drive flanges and had to readjust the linkages. I filled it with GL 4 and a half quart of Lucas. It shifts very nice and the 2nd gear shift is quiet now. There is a tab with a hole that is the center of the weight of the tranny and if you use that to raise it up from that it makes installation and removal easy.
 

MolaKule

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Given the manual recommendation (why the wide factory range and how to pick one?) and the temperature range I will be driving, which letter class should I be focused on? C, D & E?
Most of the transmissions of that era used [email protected] fluids so Amsoil MTF

https://amsoilcontent.com/ams/lit/databulletins/g2080.pdf or

Redline MTL


should work well.
 
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