[Vwdiesel] very leaky driveshaft seal
James Hansen
jhsg at sasktel.net
Tue Oct 17 02:11:08 EDT 2006
Evans Antoniou wrote:
> hi all,
>
> i have an mk3 jetta 1.9TD AAZ engine.
>
> about 8 months ago i had the seal changed due to
> prevention as i was doing the clutch work at the
> sametime. now there is a large leak from the
> driveshaft seal where the hub (cup) attaches to the
> tranny (5sp).
Okay, you changed which seal, same one as is leaking, or the one that is
hidden when the motor is mated to the trans?
>
> i brought the car to the local transmission shop and
> they thought it was a bearing in the tranny causing
> the oil leak but they did not even drive the car
> (only assumption) and i had to rebuild the tranny - i
> think this is BS because the tranny drives great,
> there is no rattle, no funny noises - tranny has been
> driving the same ever since i purchased the car. i
> tranny might have around 250 000 km.
If it is an output driveshaft seal you are referring to, then yeah, you
can tell without driving it. you go underneath, and grab the cv shafts,
then try to wiggle them up and down. If they move LOTS, then the seals
will be leaking because of worn bearings on the crown gear, the one that
the output shafts are coupled to via the differential gears. yeah, I
know, lots of words if you are unfamiliar with it, but the last bearings
on the way out of the trans on either side of it that support the shafts
that the CV joints bolt to wear prematurely if the trans is ran low on
oil.... the diff is the highest thing in the case, and the bearings
starve if the oil level is low. Only way to actually repair the trouble
is to replace both bearings. changing seals is a stop gap measure, and
they will fail again if there is excess play. Excess meaning you can
discernably wiggle the shafts up and down, and you could measure this
free play with a tape measure, not a dial indicator.
>
> now i am new to troubleshooting tranny issues but does
> the tranny misfunction in any way due to the leak
> except more noise if there is no oil left?
Less oil equals more noise- you hear the crown and pinion gears howling
in pain, and the bearings that support them wear.
>
> is this a huge job?
Huge enough if you are new to it.
Just get it fixed, and try to watch over someone's shoulder if they are
cool with that. You can learn lots for next time that way.
A minimum you need a bentley manual before tackling the job. Remember
that these are factory manuals and that they are not step by step do it
yourself home handyman manuals either. They ASSUME you already have
enough mechanic skills to be working in a shop. It's something like, it
will say "remove transmission from car." without including a step by
step procedure to accomplish this. But, that said, when you do get to
the model specific stuff, or the dirty little tricks that the designers
like to pull on us to get stuff apart, they will usually make mention of
the trick you need to do the task at hand.
>
> i have a 1.6L diesel (non turbo) tranny and is this a
> direct swap?
No, not really.
It can be, but with some effort.
All vw stuff is backwards compatible, but not forwards. That is, new
stuff fits into old, it has all the mount holes etc. New stuff wasn't
invented yet when the old stuff was made, so you will be lacking
mounting holes etc, on the older 1.6 tranny.
In my limited experience, it is waaaay better to rebuild what you have,
then you know what you have when done. If you rebuild it to as new
condition, then you have a tranny that is as good as new. Getting a
different used one in many instances, is just buying someone elses's
stuff that needs fixing, and you wind up diving into it eventually anyway.
Yeah, I'm a bit cynical
-james
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