Syncro gearbox lifespan

[HarryMann]

Andrew, he begged me to sell him the R4, so I complied (ever tried changing a starter on one )

I know where you're coming from though...

....


...


...



A severe lack of bad experiences with transmissions

[syncrosimon]

My dad who had 5 brand new T3, all 1.9 dg's, did around 130,00 miles before trading, he never had an engine problem, but two gearboxes started whinning at those miles.

In my experience the wasserleaker is more reliable than the gearbox.

[syncropaddy]

Andrew, he begged me to sell him the R4, so I complied (ever tried changing a starter on one )

Couldn't be any worse than a 2000 one litre Polo ......

I know where you're coming from though...

I think you do Clive!

This is a scan of an official VW printed document on the subject of gearbox and differential oil for T25 Syncro and 2WD vehicles. Every T25 that left the factory had this document in the glovebox. I even have it in German if anyone would like to see it.



For those of you who cant see very well...........

[Aidan]

does not need changing for vehicle life 10 years, last scheduled service is 90k miles, 100k throw it away and buy a T4

Note also that the oil and any additives used in production may differ from that available to the consumer

service schedule does however state that level should be checked so if your box weeps at all the level may not be correct and especially because they put less oil in the 2wd petrol box in order to give them an easier gear shift they are prone to running low with disasterous results for the mainshaft bearings and especially the 3rd/4th synchro parts, I can tell you that 80% of third gears have excessive cone and synchro ring wear due to lack of lubrication

note all syncros had 4.5 litres regardless of engine type

note the petrol engined 2wd vans gearbox is tilted more towards the front of the vehicle so the oil level in the differential housing is lower anyway, and then they put less oil in ? Go figure.

VW fit a 4 pinion differential in a 2wd 2.1 van but not in a 2.1 non difflock syncro, again go figure
VW fit a 4 pinion differential in a 2wd 2.1 van but not in a 1.6TD with more torque at lower revs, again go figure

VW fit a 4 pinion locking diff in the gearbox on a syncro but only a 2 pinion one in the front, even on a 16" with difflock where they uprated the front outer CV joints, again go figure

2 pinion front diffs are very prone to internal wear due to the loads on the cvs and the crap access and awkward changing procedure meant they fitted removeable inner boots so you can relube insitu to try and help reduce the wear on the cv joints which is transferred to the output flanges and ultimately the differential, but in practice how may inners get serviced before they fail ? hence the high wear rates seen on front diffs

[syncropaddy]

Interesting, 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.

This is an interesting statement even if its a light, throw away statement. It is, of course nonsense if you think about it. I have two official VW Service Record Books, one in German and one in English. The German one, on page 10 has 4 sections to it, the first being the 1000 km service, the second being its first 12 month service with no distance recommendation. From that point on, it recommends that the vehicle is fully serviced every 12 months or 30,000 kms (with engine oil changes every 7500 kms). It has 26 sections for this 12/30,000 full service. Based on that information, VW calculate the Service Life of the Vehicle to be 780,000 kms or 26 years.

OK so even if you half that distance figure to 390,000 kms or close to 250,000 miles it is still twice the figures quoted by Aidan above. I have an original RHD Syncro with its original gearbox and gearbox oil with almost 250,000 miles on it and a LHD Syncro that had its box done at 264,000 kms. The report on the LHD box at the time stated that it was "quite dry and tidy" "no major defects" "Wear on synchros and fur on plug suggests fair mileage" and "not previously repaired". The report on the front diff remarked that a balance weight had come off the VC but as this was being changed for a front locker, there was no report done on the original diff. I checked the comprehensive service history that came with the Van and nowhere does it say that the gearbox oil was changed. Why did I get Aidan to refurb the box? It had a ridiculously low final drive and I wanted it changed.

Another thing to consider about this is that as manufacturers generally dont recommend changing the box oils, the oil manufacturers themselves design their products to cater for this. Oil has a bedding in period before it really starts to lubricate to its design brief performance and by changing it too soon (12 months/20,000 miles) you are actually accelerating the wear and damage to the gearbox. Check it out, its on the internet.
I had lengthy discussions with a Technical Manager of Duckhams some time ago when I was racing Formula VW. My engines were seizing after 4 or 5 races. Why? I was changing the oil after every meeting for fresh oil and it wasn't there long enough to do it job and was breaking down under the extreme conditions of racing! Solution - I stuck a rebuilt engine in the back of the wife's Beetle and drove it for 3000 miles. I never had a seized engine again and used the same oil for 2 seasons. I also ran ATF fluid in the gearbox ....

Conclusion:

Gearboxes dont fail due to lack of oil changes, gearboxes fail due to abuse and lack of oil. You dont need to change your gearbox oil and VW say so.

Can someone who is qualified categorically prove that gearboxes fail because the oil wasn't changed please step forward - and I mean qualified in the subjects of lubricants and gearboxes - and prove me wrong.

[syncropaddy]

service schedule does however state that level should be checked

No it actually says in the manual that the gearbox and front axle differential does not need checking. Its there in black and white in the first picture

[syncropaddy]

does not need changing for vehicle life 10 years, last scheduled service is 90k miles, 100k throw it away and buy a T4

Note also that the oil and any additives used in production may differ from that available to the consumer

service schedule does however state that level should be checked so if your box weeps at all the level may not be correct and especially because they put less oil in the 2wd petrol box in order to give them an easier gear shift they are prone to running low with disasterous results for the mainshaft bearings and especially the 3rd/4th synchro parts, I can tell you that 80% of third gears have excessive cone and synchro ring wear due to lack of lubrication

note all syncros had 4.5 litres regardless of engine type

note the petrol engined 2wd vans gearbox is tilted more towards the front of the vehicle so the oil level in the differential housing is lower anyway, and then they put less oil in ? Go figure.

VW fit a 4 pinion differential in a 2wd 2.1 van but not in a 2.1 non difflock syncro, again go figure
VW fit a 4 pinion differential in a 2wd 2.1 van but not in a 1.6TD with more torque at lower revs, again go figure

VW fit a 4 pinion locking diff in the gearbox on a syncro but only a 2 pinion one in the front, even on a 16" with difflock where they uprated the front outer CV joints, again go figure

2 pinion front diffs are very prone to internal wear due to the loads on the cvs and the crap access and awkward changing procedure meant they fitted removeable inner boots so you can relube insitu to try and help reduce the wear on the cv joints which is transferred to the output flanges and ultimately the differential, but in practice how may inners get serviced before they fail ? hence the high wear rates seen on front diffs

None of that says you have to change your gearbox oil regularly. It says that lack of lubrication and low oil levels can cause failure. I'm not arguing that. Changing your oil regularly will not help these failures - how can it?

[andisnewsyncro]

This all makes interesting reading; according to my papers, mine had a new gearbox at 111000 km when it was just over ten years old.

All I know is it drives a lot nicer since the gearbox and front diff oil was changed - Cheers Si

[John Potter]

I've read all this with some interest and I reckon that Aidan makes a lot of sense, fits in with my empirical observations having had a number of high mileage (250k+) Saab's and Volvo's which have had the gearbox oil changed at 100k ish intervals, plus 4 seasons of racing in Westfields with ford gearboxes.

I'm really dubious that you can cause problems with changing the oil too often (though possibly if its every few miles like in a race g'box its different - I didnt change mine and it was fine but had only done a few 1000 miles inc road use) so common sense says change it. Its the actual age as well as the mileage and the type of use that matters. I dont think much of the quoting of manufacturers stuff from 20 years ago - it proves nothing at all (bet the Prius handbook dosnt mention the brakes ........)

Hum, swear filter on F.o.r.d up there ?

[jebiga41]

Can someone who is qualified categorically prove that gearboxes fail because the oil wasn't changed please step forward - and I mean qualified in the subjects of lubricants and gearboxes - and prove me wrong.

Applies to bikes but this is what Castrol say on the subject

The stresses placed on your clutch and gearbox are some of the greatest on your bike, making the gearbox oil one of the most important components.
Regardless of the manufacturer’s specifications, ideally you should change gear oil every 6,000 km (just under 4,000 miles). Transmission oils will deplete over time and lose their ability to protect the gear and the clutch. Use only specialist motorcycle or scooter gear oil!

http://www.castrol.com/castrol/generica ... Id=7010993" onclick="window.open(this.href);return false;

Aidan what oil do you reccomend for a gearbox again?

[syncropaddy]

Can someone who is qualified categorically prove that gearboxes fail because the oil wasn't changed please step forward - and I mean qualified in the subjects of lubricants and gearboxes - and prove me wrong.

Applies to bikes but this is what Castrol say on the subject

The stresses placed on your clutch and gearbox are some of the greatest on your bike, making the gearbox oil one of the most important components.
Regardless of the manufacturer’s specifications, ideally you should change gear oil every 6,000 km (just under 4,000 miles). Transmission oils will deplete over time and lose their ability to protect the gear and the clutch. Use only specialist motorcycle or scooter gear oil!

http://www.castrol.com/castrol/generica ... Id=7010993" onclick="window.open(this.href);return false;

Aidan what oil do you recommend for a gearbox again?

That site says nothing about changing gearbox oils in a car! Tells you how to change a bulb though .....

[John Potter]

[quote="syncropaddy
That site says nothing about changing gearbox oils in a car! Tells you how to change a bulb though .....[/quote]

how does the oil know its in a car and not a bike ?

[syncrodoug]

Do we have a tribologist in our midst?

[KarlT]

"Once more into the breach my friends!! Once more!"

Don't all opils break-down? After prolonged use at high temperatures, under load, for year after year & tens of thousands of miles, wouldn't any oil start to lose some of its properties? Or is gearbox oil special?

When I got my 'multivan' with 94,000 miles on it, just seemed logical to refresh all the fluids & lubricants. To me anyhow, but hey each to there own.

Bet VW didn't mention cutting the rot out of my rear seams either!

[toomanytoys]

FFS is this still dragging on..