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Discussion Starter · #1 ·
I want to start by giving as much information as possible to eliminate the extra questions but will continue to answer any future questions to the best of my knowledge.

The car is a 2004 tdi. Two years ago the tiptronic broke (shocker) after ~150k miles. Last spring I got in touch with Frans and ordered a 5 speed manual DUK code kit. I used a south bend stage 2 endurance clutch and single mass flywheel. For the ECU flash I used Malone and also installed their stage 2 tune. While I had the car apart and exposed I also did the timing belt, water pump, and balance shaft delete. I installed new engine mounts including the snub mount, but did not get new transmission mounts (are on the list)

Car worked great and ran flawlessly, for the most part, I have some other issue but it is not drivetrain related. The car is my daily and I drive a fair amount (15-20k miles a year) Back in the summer I took the car for a spirited drive up US 129 The Dragon one Saturday. I had no issues and did not have any for another ~350 miles and 4 days.

The issues started one day on the way home from work. I have about a 15 mile drive on the interstate, 5th gear the whole time. When I got off my exit I pulled over to take a call before I would lose service. After sitting for about 15 minutes I started to go again and as I shifted into first I noticed it took a little extra effort to do so, like there was a steady resistance that wouldn't let me slide it right into gear. Seemed odd so I put it into neutral and tried first again and it went right in, no issue. So it seemed like it had gone away. The next problem was that third gear ground as I shifted into it, so obviously the synchro had failed.
Over the next few weeks the shifting into first issue came and went and seemed very sporadic. I rev matched or skipped third when I could to reduce the grinding. I was busy and did not have time to research and could not stop driving the car back as I had no other vehicle at the time.
After about 3 weeks other gears began to be difficult to shift into and the occurrences of the difficulty increased, but was still sporadic. When I say they were difficult to shift into, I mean it physically requires a much larger amount of force to move the lever forward or back. Its not notchy or shaky, its very smooth but its like I'm trying to swing a bat in a syrup pool, and this is whether the car is on or off, clutch in or out. Around this time reverse became completely unusable. As I attempted to slide the gear lever down (to the rear)it went most of the way but as I let the clutch out I can feel the gears just barely touching but something is not allowing me to move them all the way. Roughly 5 weeks after my first issues arouse, all gears but 3rd became impossible to shift into. Luckily I wasn't far from my works shop. I have grenaded a transmission before and know what it sounds and feels like, and that never happened. While driving in third it made no weird noises or grinds and went into and out of just fine, other then the grind while moving. After a week or so I pulled the transmission figuring no matter what I want to replace the synchro, it needs to come out.

I'm pretty knowledgeable about cars and can and have done 95% of all work that has ever been completed on my vehicles but I cant wrap my head around the witchcraft that goes on inside transmissions and transaxles. With that said I will be having a professional do the work on my transmission.

I will confess that I doubt myself that I properly bled the clutch, and there may have been air in the system. I say this because I had a busted brake fluid reservoir but replaced it before I bled the clutch. I also had a moment or two while stopping a steep hill where the brake pedal was very soft and wetn allt he way to the floor and I needed to pump it once or twice, almost as if there was air in the system, so my concern is possibly air got into the clutch system as well? I know its a far shot but murphys law hits me hard constantly.
After pulling the transmission I inspected the clutch, flywheel and pressure plate and they seem fine to me and others agree.
The shifter moves freely up down left right in a circle after being disconnected from the transmission.

When the transmission goes back in, I will include new transmission mounts and will also be replacing the bushings in the shifter assembly, as to eliminate these being a culprit.

So here come my questions and more importantly I need the Passat wizards knowledge.

Shift related:
What in your opinion happened and what is needed to fix it?
Is it the bushings in the shifter assembly? Would they cause the difficulty? Does the free movement eliminate them as suspect?
There is some type of linkage or mechanism within the transaxle that actually shifts gears I assume? Do these ever fail? And if so what are those symptoms? Are they repairable?

Transmission Related:
How different are the internals from a european DUK tdi to an american market 1.8t/vr6 manual?
I know the gearing is different for fifth but what about the other gears?
Are they similar enough that I can tell a shop its from a gas car and use gas parts to replace the synchro and other possible components?
Even if a shop is able to do the repairs what is the likelihood the fix would be less than $540? (I have no clue what the potential cost could/would be as I've never really paid a mechanic) Frans's market shows that to be the cost shipped of another transaxle.

I know this is tdi heavy but the questions are more transaxle related so I posted here.

If you have made it this far thank you so much for your time and any information would be tremendous!
 

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If the synchros ate themselves while doing nothing, I wouldn’t rule out the gear oil. You need need to use a GL-4 (not GL-5) spec oil.
 

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First thing I'd do is visually inspect the tranny for leaks, debris jammed up there by the shifter rod, etc. it's free. Ive seen squirrel nuts cause shifting problems. After that I'd check gear oil level, if it's low, add till you get overflow, that's pretty cheap too. That's a start that wont cost much. I just changed my tranny oil with Liqui Moly full synthetic 75w-90 and my shifting was noticeably smoother, wasn't really having shifting issues in the first place but noticed a difference nonetheless.
 

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I think you had air in the clutch hydraulics and that may have caused the grinding in 3rd as well. The clutch is not fully disengaging, so the gears are still linked to the engine and that does not allow the synchro to do it's job.
 

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Discussion Starter · #5 ·
It was not leaking fluid and I didn’t notice any foreign objects in the general area. When I get it rebuilt I will refill/overfill with a quality suggested gear oil. I will also be sure to better bleed the hydraulics.
Not all the of synchros went, just third ground. The other gears were just difficult to shift into, but they never did grind.

Anyone have a guess about the synchro replacement and compatable/gear ratio?
 
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