gearbox oil recommenmdations/advice needed

[nrxx]

Apologies, I initially responded to a forum search for MT90 and then realised it was in the synchro forum, should have posted here.

Hi

I'm feeling slightly paranoid as I'm now on a s/h box (1.9dg/4spd manual) following failure of original and want to make sure I give it every chance I can! This seems to be MT90 or MTL. my questions are;

can anyone give me feedback on performance? I suspect that as a daily driver on fairly long trips and unknown internal condition the MT90 is the one to choose, although I have heard that it can still be a bit notchy when cold?

Can I just drain on level ground and refill or is there some strange ritual cleansing involved?

and,

If I buy 4 quart bottles will I have enough? I think I will but... any thoughts welcome.

Thanks
Nick

[Red Westie]

I'm no expert but I would have thought straight 90 weight gear oil would be too thick (too higher viscosity) I would be looking at one of the newer Semi Synthetic multigrade gear oils with a 75W/90 weight.
Using a very thick oil will result is 'baulking' crunching gears especially when cold.
I believe Aidan recommends something along these lines for improved gear change.

Martin

[Red Westie]

Aidans advice:

gsf semi synthetic Fuchs Titan 98048A 4 litres about £20
or any good GL4 spec 75w/90 or 80w/90 gear oil

Martin

[nrxx]

Thanks
I should also have specified the oil more! As per Wiki

'Thank you for contacting Red Line Oil, originally in the Vanagon VW called for either an 80W or a 80W-90 GL4 fluid according to my guide. The MTL is an 70W80, a suitable replacement for the original 80W, the MT-90 is a 75W90 viscosity a suitable replacement for the 80W90. You could use either and I would base my recommendation on the operating conditions and/or transaxle condition.

I would recommend the MTL if most operation was at relatively low temperatures and cold shift ability was of prime importance. If it is typically used in higher operating conditions, elevated temperatures and/or there is some noise in the transaxle, I would recommend the MT-90. I hope that helped clear some of the confusion.'

This is a high end fully synthetic GL4 gearbox/transaxle oil. That said, Fuchs is what I use, very happily, in the engine and is considerably cheaper than Redline!

OK, can anyone give me a definitive capacity? In the past I filled to the bottom of the filler hole. Is that still the best option or should I measure out 3.5 ltrs as per Haynes?

Sorry if these seem basic questions, I am, as I said before, slightly paranoid.

Thanks
Nick

[Aidan]

personally I'd go with 4 litres rather than 3.5, the diesel takes 4 and it's more level, the reason for less oil is to ease the gearchange in the lower gears when cold, but I'd rather have good lubrication to the top two gears when hot on a run cos that's generally where they go wrong all things being equal
have also replied on syncro forum

[toomanytoys]

I also replied on Syncro forum..

[nrxx]

Thanks everyone, including those who responded on the synchro forum. I think it's going to be 4ltrs of Millers then.
Nick

[toomanytoys]

No "H" in Syncro (VW's 4wd system)

[faggie]

i only use mobil shc fully synthetic and never had any problems

[CovKid]

Amusingly, just before Christmas I bought a new oil filter and odds and ends from GSF, and thinking of my discount, right at the end I said "80/90?"

- he gave me a can of 80-90 gearbox oil. Being as he had it I bought it anyway but watch that one

[nrxx]

This has turned into an 'interesting debate' over on the Syncro forum. I was about to ask another question (confirming the GL4/5 classification of Fuchs Gear Syn) and would you know it, he'd gone and answered it in advance (it's ok)!

I thought it might help if I post the GSF part no's as they appear to have changed from the code Aidan (and others), have quoted.

980AA0650 FUCHS TITAN GEAR OIL 75W-90 1L GENERAL USE-SYNTHETIC BASE 5.15
980AA0660 FUCHS TITAN SYN GEAR OIL 75W-90 4 L AS REQUIRED (GL4/GL5 SPEC) 15.80

Hope this helps someone.

Nick

[Aidan]

cheers for the updated part numbers