Syncro gearbox lifespan

[binner]

Hi all

My Syncro gearbox is functioning fine at the moment but i want to make sure that i'm doing all i can to ensure it stays that way.

The VC had gone passive and the propshaft had some vibrations so i've removed that until i can get a new VC and rebuild the shaft.

The van has done 130,000 miles and i'm fairly sure from the history that it is genuine. It is on its second 1600TD.

I've no idea what oil is in the box but i know the previous owner topped it up as there was a slight leak from a stripped thread in the plate at the front. This has now been helicoiled and there are no leaks.

Should i drop the oil out and replace with the correct synthetic? I doubt the previous owner used synthetic and as i understand you can't drain it all out with the box in the vehicle so will that mean i'm putting synthetic in with mineral and is this a bad idea?

What sort of mileage is typical for a syncro box before a rebuild is needed assuming good maintenance?

Cheers
Gary

[HarryMann]

What sort of mileage is typical for a syncro box before a rebuild is needed assuming good maintenance?

Totally indeterminate, but they often get to 100,000 or a lot more, and sometimes don't!

Quite a few drain and change to a 75W/90 semi synthetic. e.g. Budget SX 75W90
GSF now do a FUCHS synthetic gear oil of that viscosity range
Red-line MT90 is supposed to be the best, but very expensive.
Some stick with a quality GL-4 spec. mineral oil, not supposed to use GL-5.

The main reasons are: a) Change to a new oil, imsurance b) attempt to improve cold gearchanges (into 2nd gear usually)

About 4 litres should do it, bottom of oil fill plug (some overfill and then remove plug on level ground to drain to correct level)

Usual warning - make sure you can remove the filler plug before you drain it!

[toomanytoys]

Yep.. depends on how its been used and abused etc..
mine was a working truck and was low miles (140k km) but box was noisey (main pinion bearing) Aidan rebiult it and found it to be very nice inside.. which was good... some have done 200k without problems...

[binner]

Thanks guys, interesting to know.

I find myself constantly listening for unusual noises but over the rattling of the TD its a bit hard.

Time to change the oil anyway I think.

Cheers
Gary

[HarryMann]

.. but nevertheless, if you love your truck, then maybe start budgeting now if you have no history of the box and no knowledge of a rebuild. There really aren't that many about that haven't been pulled apart before methinks... or put it this way, there seems to be an awful lot that have!

[Boltze]

The gearboxes were made for 300.000km. I had to repair mine the first time on 280.000km, the synchroniser ring 3/4gear was broken.

[Aidan]

Iteresting, the Van was designed for 100000 miles 160000 km service life , last official service at 150000km, with no gearbox oil change, throw it away buy a T4. Ditto the T4,100k miles buy a T5.
Gearbox was designed to last that long imho, with 1 in 5000 sort of failure rate, but I think in reality the 4wd version often didn't last as well as that, due in part to lack of care of maintenance of whole drivetrain, well over half the boxes I've seen have previously been rebuilt to some extent, there were less than 50000 syncros worldwide, there's a diminishing pool of vehicles, diminishing pool of vcs for refurbishment hence increase in failed cores and surcharges, fewer whole gearboxes for parts.
And it's an evolutionary dead end in these days of four platform motor group worldwide industry so unlikely that the T25 will be made again I reckon, otherwise it would already have gone back into production somewhere, it's over 6 years since the plant came out of use in South Africa, in which time the Brazilians have carried on building bay based things and evolving that with new body panels and a watercooled in line four engine etc....rather than going, ah, T25 more modern, we'll make that.....just my opinion, be nice to be able to ask VW for clarification, but of course they won't tell you anything cos of commercial confidentiality. Someone knows where the T25 production line is/was if it's been scrapped, anyone in SA know ?
I had a chat with INA's UK manager yesterday so hope to get a real update on the ongoing availibility of their bearings for these boxes in the next week.

[HarryMann]

The gearboxes were made for 300.000km.

Well, they didn't succeed with more than half of them then

[nrxx]

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

[syncropaddy]

My box had 260,000kms up when I gave it to Aidan to refurb. He said it was in good condition and didnt really need doing at that time but I decided to do it anyway

[toomanytoys]

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

Personally, I wouldnt belive the hype behind that particular brand.. I know of at least 3 gearboxes that have failed in not that may miles after a "precautionary" oil change..
I'd be using the Fuchs Syn gear avialable fro GSF.. (Thats whats in my Syncro..) or poss the Comma SX 75w90 as I have that in my 2wd Caravelle for 10 years (2 changes) thats on its original gearbox that must have 300k miles on it...

[Aidan]

Personally I wouldn't bother with the redline, Millers do an oil just as good for half the price which is used by the racing fraternity in the uk and is belended in the uk rather than shipping stuff from america, and tbh the Fuchs Titan Gearsyn from GSF 98048A for £20 is the same spec and seems to be excellent and is what VW used to sell us for the syncro for £15/litre plus
if it's £20 oil you can afford to change it annually and check the drainplug and get advanced notice of rebuild time, if it's £90 are you going to want to drop the oil regularly or rely on it to protect you ?

[toomanytoys]

Trouble is.... he's in OZ........ lucky git.....

Might depend on whats available there.. Aidan.. can you ask the gear chap?

[Aidan]

didn't spot that
I'd recommend whatever the Holden raceboys use then, pretty sure it won't be redline

[Simon Baxter]

belended in the uk

Thats one way of putting it!