Is it worth changing gearbox oil?

[smilespergallon]

You might find that oil is a bit harder to get into gear when very cold.

You're right. It snowed today in the UK and the temperature was around zero.

Getting in to first and second gear was noticeably more difficult. Not impossible, but definitely takes a bit more effort than it did before. The other gears such as third and above are okay, just first and second were the stiffer ones, not sure why.

So yeah, it's not annoying enough to change it in the meantime, but if I change it again in the future I think I'd probably go for the extortionate genuine VW oil, or try that Redline MTL that Pudding suggested.

So yeah, Fuchs Titan Sintofluid is fine when it's about 2 celsius and above, but below that and it's harder to get in to gear.

[pudding]

As a guess, I'd say it's because 1st and 2nd are the biggest gears, and therefore harder work on the syncro rings to speed match them.  Syncros don't work well with thick oil, which is probably why VW keep changing the formula. 

Normally improvements can be made using aftermarket fluids in most cars, but VW's gear oil is one example where it simply cannot be improved upon. 

I vaguely remember a post on VWVortex years ago where a chemical expert analysed VW's gear oil and said it's way better than anything even in the racing oils market.

I can't remember the exact Redline flavour I used as there's a few of them.  It might have been the 75W80 flavour.  Redline's shockproof is also known to improve the shift on VW boxes.  Not always from stone cold, that will take some trial and error, but generally when hot during high rpm shifts, where the stock oil can struggle.

You could take a brave pill and sling some automatic transmission fluid in it    It's standard practice in E39 M5s and some other manuals of that era.  Those boxes are even worse than VW's for 1st-2nd cold shifts, but auto trans fluid totally transforms them.

[smilespergallon]

You could take a brave pill and sling some automatic transmission fluid in it    It's standard practice in E39 M5s and some other manuals of that era.  Those boxes are even worse than VW's for 1st-2nd cold shifts, but auto trans fluid totally transforms them.

Thanks Pudding.

So if I were to go the brave route, are we talking about 100ml of ATF to thin the current oil down a little bit?

[pudding]

You could take a brave pill and sling some automatic transmission fluid in it    It's standard practice in E39 M5s and some other manuals of that era.  Those boxes are even worse than VW's for 1st-2nd cold shifts, but auto trans fluid totally transforms them.

Thanks Pudding.

So if I were to go the brave route, are we talking about 100ml of ATF to thin the current oil down a little bit?

Nope, drain all the gear oil out and replacing it with transmission fluid 

It was on my to do list for mine but I never got around to it.  Something like LiquiMoly TopTec 1200 would suffice.

It seems like an alien concept putting automatic transmission fluid in a manual gearbox, but auto boxes also have meshing gears inside them like a manual box, and ATF does them no harm     VW's MTF is so thin, it's probably not far off ATF when hot anyway.

It won't hurt to try it.  Just drain it out and put MTF back in if it doesn't work out    You'll soon know, but just drive it gently in your local area at first.

Obviously I'm not pushing this as a wide scale recommendation, but merely as an experiment to see if it helps, so do it at your own risk    If it doesn't hurt M5 gearboxes, I can't see it harming a VW box either tbh.  Some OEMs even use ATF in their Manuals 

[FatWelshBoy]

Ebay item 404168239273 and multi buy 3 bottles at £21.61 each.

[smilespergallon]

Just wanted to give a quick update in case anyone finds this thread in the future.

I ended up changing the gearbox oil from the Fuchs Titan Sintofluid SAE 75W80 GL-4 I put in a few months ago back to the official Volkswagen Gearbox oil (part number G 052 171 A2).

From all my research it seemed like the Fuchs would do the job and might have been what Volkswagen use but rebranded. However, it was slightly thicker and it took a bit of effort to get in to first and second gear when it was really cold outside. I had some time (and money) on my hands this weekend so I changed it back to the Volkswagen oil.

It's not freezing cold here at the moment, but the gearbox definitely shifts more easily than it did with the Fuchs Titan Sintofluid. So if you're going to change the gearbox oil on your manual Mk5 Golf GTI, it's worth splashing out on getting the official stuff rather than Fuchs. It wasn't bad, but it just wasn't perfect.

I managed to find 3 bottles of the VW stuff on eBay for about £22 each. I think they turn up every now and then.

[pudding]

Yeah the VW stuff is the best by far    Followed closely by Redline Lightweight Shockproof.

[OldGTI]

Had mine changed. Old stuff was almost black not golden like the new so probably worth doing.