Transmission violently locked up

When i say violently, i mean i came to a skiding halt. The initial symptoms were a strange noise, a rumbling and then the engine quit hard, car kicked forward, i was at a stop in neutral if that helps. Checked timing belt, good, very stiff gear shifter couldn't get it out of gear so i decided to move it forward off the road, that's when it locked up while driving, felt like i hit something. Stared it again and now it's driving fine, feels like syncros are gone on first gear... Any ideas? Shifter bearing fell apart maybe and the little balls jammed the gears?

Diff gear pins slid out.

Coincidentally i ordered some gear oil for today and had it to change it out. Old oil was full of brass shavings which makes sense if the first gear syncro fell apart. Car kicked forward and engine stalled while in neutral plus it's very hard to get it into first now

oilhammer said:

Diff gear pins slid out.

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You know he's usually right, right? Find that differential gear

Of course, and i mean no offence here just trying to learn, however the way it kicked forward while idling in neutral with the clutch out does not seem to support the diff pin theory (as the diff was not spinning at the time/wasn't moving) unless I'm missing something? Syncro breaking apart would jam the input and output shaft together and account for the very high level of brass in the oil as it got shredded. I'm any case, car is driving fine now but first gear is very hard to get into. Second gear is harder than normal as well, but the oil change did help.

Anyways, if I'm wrong i think i learned more by theorizing hehehe

either way you'll have to open the tranny up anyway....then you'll probably know what happened.

Victor Huge said:

Of course, and i mean no offence here just trying to learn, however the way it kicked forward while idling in neutral with the clutch out does not seem to support the diff pin theory (as the diff was not spinning at the time/wasn't moving) unless I'm missing something? Syncro breaking apart would jam the input and output shaft together and account for the very high level of brass in the oil as it got shredded. I'm any case, car is driving fine now but first gear is very hard to get into. Second gear is harder than normal as well, but the oil change did help.

Anyways, if I'm wrong i think i learned more by theorizing hehehe

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A couple things. You were moving when it locked up. Being in neutral does not matter, the diff was still turning So the diff gear pin slipping out or the ring gear rivets shearing is very likely.

Learning about mechanical things by theorizing is kinda a wasted effort because it doesn't really take into account how something actually works. OH's post was not theory or even a WAG. His diagnosis of the problem was based on years of experience and known history of differential just like the differential in your transaxle.

Irregardless of what your "Theories" tells you, dropping the T/A and dissembling it should be your next step so that you have actual facts.

In this case, it does sound like it is NOT the diff pins. No idea what it is, but the transmission will almost certainly need to come out and be opened up.

These transmissions are usually pretty tough, but somehow people find ways to break them, LOL. I'd sure think by now I would have broken one, given the hard use I often place on them, but knock on wood I have not.

The OP's original post had some contradictory comments. "Skidding to a halt" implies the car was moving, and that is why I said diff pins. But then later it was "at a stop idling", so I guess it was the latter and not the former, as it couldn't be both. Unless Einstein was wrong.

Haha nicely worded Oilhammer, actually both are right as it was two separate events, permit me to clarify.

I was sitting at a light idling in neutral with the clutch out when i heard a noise start, get louder and then the car kicked forward as the engine stalled. I immediately checked the timing belt which looked good. Restarted the engine but i could not get it out of gear, the shifter was super stiff. I eventually managed to get it into neutral but releasing the clutch felt like it was still in gear as it moved a little out the engine tone dropped. Waited a bit decided "fcuk it" restarted, drive off in first, had time to think "hey i think I'm good" and that's when i had the violent lock up with the tires skidding. After that it seemed to drive fine and has been ever since. When i changed the gear oil, it was brassier then a jazz band

Maybe both - trashed synchro and a sliding diff pin?

I'd be sourcing a spare transmission either way.

I wanted to say i think i solved the problem. It involved reducing the engine displacement by .5 and replacing the "D" on the back with an "S"...

Yeah...

So that...

I'm kind of flip flopping back and forth, both angry with my decision and excited. I was literally in tears at the thought of getting rid of my mk4, so many memories, so many years... Did practically all my own maintenance minus the first timing belt and shocks, met lots of friends through this forum, i honestly can't see myself not clattering away... We'll see, they're having a hard time finding a Wolfsburg in manual with fog lights

/

Just a quick update, not getting rid of my mk4 nor getting a new car anymore. If you can believe it, I like it better with no first gear syncro, it's a lot more consistent with how it goes into first compared to when I had whatever was left of the sycro. I used the have moments where it would take multiple attempts to get in gear as it just wouldn't go and now it pretty much always engages, sometimes with clunk, but it always engages. You don't really need a syncro for first gear if i'm honest.

So, no syncro worked out.

Victor Huge said:

I used the have moments where it would take multiple attempts to get in gear as it just wouldn't go and now it pretty much always engages, sometimes with clunk, but it always engages. You don't really need a syncro for first gear if i'm honest.

So, no syncro worked out.

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Have you tried putting it in 2nd first then 1st?

No, why?

My old MK4 had a similar problem with the first gear synchro/lack thereof. I'd have to treat it like older cars that didn't have reverse synchros and just shift into another gear first. It also guaranteed no one else could drive the car!


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I use to do that with a lot of the older cars that didn't have synchro's in 1st either.
(Real old)
Can't hurt trying.

I usually just let the clutch back out and back in. I think that lets everything line up in a different position.

So you're saying the transmission seemed to have a catastrophic failure, you didn't do anything to fix it, and the car is still fine to drive.

These Mk4s are really indestructible.

Mike_04GolfTDI said:

These Mk4s are really indestructible.

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Except the plastic bits!

UhOh said:

Except the plastic bits!

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And they make a heck of a visor. I use the heck out of mine and they work like new.

whitedog said:

And they make a heck of a visor. I use the heck out of mine and they work like new.

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Driver's in my blue Golf is a bit limp Daughter's visor, driver side, couldn't take an impact to the mirror: someone managed to break the mirror- how the? So, yeah, 80% good here (one car out of 5 has an issue from normal use).

Center console, rear hatch plastic connection bits are near single-use

Of course, this is all off-track/topic (but, perhaps, one might be more thankful to have broken plastic bits, which can be very annoying, overs something like a broken transmission).

Mike_04GolfTDI said:

These Mk4s are really indestructible.

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It sure feels that way. I've gained loads of valuable experience with my mk4 and thankfully the time has gone where I obsess over every odd noise but I have always taken care of maintenance fixing anything that broke and the reward has been close to 9 years of trouble free service and 200,000km of my driving, it's currently at 467,000km. Only recently did I have a few "we need a new car" moments: Car died while driving (sending unit), sounds like the turbo is going to blow (egr pipe broke) and finally this transmission thing.

The alh is a fantastic engine, I used to work at a VW dealer and one came into the shop with two destroyed lifters, still running! Wish i could find that picture!

I haven't had too many issues with the plastics, the interior hasn't held up too great though but mostly had issues with electrics here and there.

+1 on going back and forth between gears.

I go 1-2-1 when shifting into first. Most of the time that first shift into 1st is a little "clunky", after going to 2 then back to 1 it is nice and smooth. If I don't do that it will occasionally get stuck in 1st (have to slow down and wiggle it back out of gear). I'm still waiting for a manual TDI at the pick 'n pull but I've put almost 10k on the car like this with no problems.