GEARBOX INPUT SHAFT

[tony211]

Hi new to forum. i have problem with contaminated clutch due to oil from gearbox on a 1.6 four speed diesel t25. when gearbox was removed found excess play in the input shaft, replacing main shaft seal as leaking, there is a oil return scraper that is in the bell housing seems worn can i get replacement from somewhere, jk and vw heritage suggested 80-90 for advice as they cant supply part has anyone else had this problem dont want to re assemble with new clutch until cured also replacing spigot bearing. any advice appreciated

[Aidan]

I love the fact that the major parts suppliers refer to here for technical advice, though slightly worrying, discuss


this is too common a problem, caused usually when numpties fit replacement inline 4 engine and don't fit a spigot bearing in the end of the crankshaft of the new engine, 350miles later and the clutch is slipping due to oil contamination, they go back in, maybe fit a spigot bearing and replace the seal but it does it again, often by this time the van has a new owner and another garage trying to figure out what is happening;

sound familiar ?

either that or some sort of wierd engine is fitted using an adapter plate and there is an alignment issue, also common with certain converters

the oil thrower that is fitted in the bellhousing behind the oil seal is essential to reduce the oil load on the seal as the crown wheel is rotating at wheel speed and throwing the oil straight at the back of the seal, or it would be if the oil thrower wasn't there, it runs around 0.5mm clearance on the shaft and is grooved inside to resist the oil being drawn along it by the roatational forces

the oil thrower is not available from VW as a seperate part, it is fitted to the bellhousing just like the dowel pegs and any other interface bits are to make the complete bellhousing part of the gearbox case

one or two of the german suppliers were selling original type pressed steel oil throwers, Winkler maybe Notter ? I don't know if they are still available

when I ran out of bellhousings to reclaim undamaged ones out of (petrol ones usually ) to repair damaged ones (f...ing diesels mostly) I had to get the machine shop to make some (hand made by machinists on lathe - old school) for my customers' needs, fractionally oversize on the collar to fit slightly worn bellhousings, but if bellhousing is badly worn then it goes to the engineers for sleeving and replacement oil thrower as thrower must be centred otherwise it will run against the input shaft and wear and the cycle will begin again

choices then are replacement good used bellhousing, check out if available from Germany or failing that drop me an email

when changing the seal it is much easier to do if you remove the bellhousing, for the price of a gasket you get an easier job, the chance to check the input shaft and oil thrower properly and a look at the crown and pinion and a view of the drainplug magnet; an oil change is optional (Ralph), golf tee plug in the breather hole 1oclock on the front case and you can stand it on it's end with the mount removed but unless you know the service history of the box I'd always recommend changing the oil, and then doing it regularly, 2-3 years 20k miles max, more often if used hard, hot, towing, off road etc..

I'd also recommend that you fit a new spigot bearing when doing an engine change or a clutch swap it's the best £8 you can spend, if you have to pull the box and pay a garage to do it figure on minimum £100 labour plus whatever it costs to fix whatever is damaged (shaft, oil thrower, clutch ?) in future; the poor little needle bearing goes from stationary to running at engine speed everytime you press the clutch with the engine running with feedback load from the transmission and yet most people are happy to leave well alone even though it maybe 10 or more years in there, many diesels have the wrong one fitted , the petrol one will fit the diesel engine but doesn't have a built in seal to protect it from the clutch dust like the correct one does - in the petrol engine there is a felt seal in the back of the flywheel to protect the seal, these often get omitted or damaged if/ when flywheels changed, eg when fitting a rebuilt engine that comes with no flywheel (petrol flywheel is pretty much unobtanium new these days in UK)

AND diesel engine boys (and inline 4 engines fitted using the diesel mounts) remember to lift the back of the engine up (ratchet strap and block of wood across hatch) before trying to remove gearbox so it will easily clear the chassis and uncouple without you loading up the spigot end of the input shaft and damaging it by pressing the b..stard hard bearaing needles into the very very thin b...stard hardened surface of the shaft, this is what probably causes the majority of damaged diesel input shafts and spigot bearing failures that are all too common - having the engine at correct angle makes installation much easier too

if this can be wikied if it isn't it will save constant repitition

[ajsimmo]

Now that's a comprehensive answer! Nice work, Aidan.

[ghost123uk]

if this can be wiki'd... it will save constant repetition

Done = HERE
If anyone deems it should be in a different place, or have links added to it from other entries, etc please feel free.