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.
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.
