Manual transmission while in neutral wants go forward

[ICHIBANFILIPINO]

I've got an 03 A4 B6 with 1.8T FWD manual transmission. While in neutral, car wants to lunge forward. I've already replaced clutch, flywheel, crankshaft seal, and gear oil. And its gotten worse. And suggestions?

[caluma4x4]

Have you checked the slave cylinder, it may be leaking or it may need bleeding.

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[Turbo510]

Can the car roll easily when in neutral, engine off?

[Kevin C]

Nothing to do with the clutch, something inside the tranny is dragging. If its doing it that badly I would think you would see some metal in the oil. Does the shifter work OK? Any strange noises? It sounds like it's time for a new transmission.

[ICHIBANFILIPINO]

While in neutral in the air, front drivers wheel will spin. I havent checked slave cylinder, gonna look up location. Shifts fine most of the time, made it a habit put it through all gears before starting the car. Seems like it wants to jump after it warms up

[MetalMan]

I agree with Kevin, this is transmission related. Looks like it's one of the items you haven't replaced yet. I suspect a FWD 5-speed trans should be fairly inexpensive.

[ICHIBANFILIPINO]

It is a FWD 5speed.

[Turbo510]

While in neutral in the air, front drivers wheel will spin.

I'd expect that, but if they rotate in opposite directions, then you are just moving the differential gears. Try turning both front wheels at the same time, in the same direction. Perhaps a synchronizer is moving out of neutral position without the shifter being moved, but in any case the trans probably needs to be replaced. A Passat FWD unit might be what you will find more easily.

[ICHIBANFILIPINO]

Thanks, any particular year I should look for? I was trying to do performance upgrades, I've got a stage 1 clutch in it now. I bought the car second hand so I've been nursing it back to another better than it was. Also thinking of upgrading the turbo , but first need it to be in a reliable state.

[ICHIBANFILIPINO]

The guy said it had a bunch of emission deletes, pcv delete. has upgraded front mounted intercooler, intake system with HKS blow off valve. Downpipe

[caluma4x4]

A leaking slave cylinder will gradually release the clutch even when you hold the clutch pedal on the floor, sounds like what you're describing. Remove the coolant tank and you should be able to see the slave cylinder, above the inner CV joint roughly.


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[Kevin C]

A leaking slave cylinder will gradually release the clutch even when you hold the clutch pedal on the floor, sounds like what you're describing. Remove the coolant tank and you should be able to see the slave cylinder, above the inner CV joint roughly.


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From the first post...

While in neutral, car wants to lunge forward. I

[caluma4x4]

So I missed that bit. What your diagnoses Mr Mechanical engineer? Maybe if you tried to help instead of criticising others.

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[Turbo510]

He did try to help; see post #4 with three suggestions.

[caluma4x4]

It clearly isn't in neutral hence my suggestion, how else would a transmission drive when supposedly in neutral.

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[Kevin C]

So I missed that bit. What your diagnoses Mr Senior Mechanical engineer? Maybe if you tried to help instead of criticising others.

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Sorry you took that as criticism, It was a quick reply on my way to work.


Don't make me go full Dearhurst on you.

[Kevin C]

It clearly isn't in neutral hence my suggestion, how else would a transmission drive when supposedly in neutral.

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It has internal friction that is high enough to cause the wheels to spin. It can happen if a gear is starting to seize to the shaft its supposed to ride on.

[ICHIBANFILIPINO]

I appreciate all of the advice, and the suggestions from all. I am willing take all approaches to solving this issue by starting with the small as I am really hoping its not internal as the mechanic that installed my stage 1 clutch and flywheel along with a new crankshaft seal and gear oil. I have priced a couple used transmissions on the line. If theres any good sources I can look at that i possibly haven't come across yet that would be great and thanks now and in advance.

[EuroxS4]

The real question should be wether to clutch is correct and is it installed correctly. I have seen southbend clutches come with the wrong disc in the past. Came with a unsprung disc when it should of came with a sprung disc. Also mounting the disc backwards could be an issue.

[Kevin C]

The real question should be whether to clutch is correct and is it installed correctly. I have seen South Bend clutches come with the wrong disc in the past. Came with a unsprung disc when it should of came with a sprung disc. Also mounting the disc backwards could be an issue.

To add to that, the first post notes that it does it in neutral so its unlikely to be the clutch. Also, the OP noted it did it before the clutch was changed. I did want to mention that there is always some drag in a gear box from oil drag, and that drag will try and spin the wheels; even when your in neutral.

Things that could make this worse:

1: Thick gear lube.
2: Dragging synchro ring from a damaged synchro or miss adjusted shifter.
3: Gears with a large amount of friction to the mainshaft.

If it is tranny damaged it should be trying to creep in neutral pretty hard with your foot off of the clutch.

If its the clutch it should only do it in gear with your foot on the clutch.

If it does it in neutral with your foot on the clutch you need to reevaluate, since having a bad tranny and a bad clutch at the same time is very unlikely.

Putting the car on the lift and getting a tire to spin with the engine running can happen even on a good tranny.

Assuming that the original description is correct and this is happening in neutral and is quite severe the logical explanation is that there is internal friction in the transmission.

Regards,

Kevin

[caluma4x4]

Sorry you took that as criticism, It was a quick reply on my way to work.

Is this any better? The OP mentioned in his first post that it does it in neutral so it's unlike its the slave cylinder or the clutch.

If was criticizing you I would have called you a dumbass for not reading first post of the thread.

Don't make me go full Dearhurst on you.

okay read it wrong and took your reply the wrong way.


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[Kevin C]

okay read it wrong and took your reply the wrong way.


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Seriously, things that we type don't always sound they way we hope they will. I was on my way to work and wanted to reply to try and keep the OP on track. I hesitated for a second thinking it might sound harsh but I didn't listen to the inner voice. It was more of hey, check this out ... did you miss that? I'm not trying to sound like a jerk, it just comes naturally.

[hightime80]

Sorry you took that as criticism, It was a quick reply on my way to work.


Don't make me go full Dearhurst on you.

That is funny😂

[ICHIBANFILIPINO]

The gear oil that is in there is the Lucas brand in which the mechanic recommended , i believe it was the 75 90

[EuroxS4]

Ok here’s another suggestion. Are you sure the car is In neutral??It could be shifter linkage alignment or bent linkage perhaps. Does the car hit all the gears without issue?? Or is it hard to put into certain gears??


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[Kevin C]

Ok here’s another suggestion. Are you sure the car is In neutral??It could be shifter linkage alignment or bent linkage perhaps. Does the car hit all the gears without issue?? Or is it hard to put into certain gears??


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Another possibility is a bad shifter bushing or fork causing a gear to not fully disengage. Personal experience with cars that were on their way to be scrapped is if you pull on the shifter without putting it in gear and your foot off the clutch the synchro will try and drive the car. It doesn't do it very well but it does work.

As far as the gear lube question that lube would not cause this. As I was typing this I remembered why this seemed familiar to me. It happened to my Raider a long time ago (five speed RWD). Fifth gear was seizing on its journal and was trying to drive the entire transmision like it was engaged. When rolling that made it hard to get into the other gears. In neutral with my foot off the clutch it tried to creep forward. It had a few other problem, but that was the main one. The hotter the unit got, the more the lube thinned the worse it got.

If one gear is always easy to shift into and the others are a struggle that is an indication that the easy shifting gear has a problem.

[ICHIBANFILIPINO]

All gears shift fine while in neutral, with car on and clutch pedal compressed. i shift into each gear while foot off the clutch and it will not go into gear but I can feel it want to but unless I press the clutch, it will not. Now there has been a couple of times, less than a handful that when I put it into 1st, it feels like it's trying to take off in 3rd.

[EuroxS4]

My guess is the shifter linkage is out of alignment of you have a bent rod in the shifter linkage and damaged linkage. Based on your last statement saying handful of time it was trying to take of in 3rd,it shouldnt be a guess if it in 3rd but looks like it in first or close clearly I would start with linkage. To the simple stuff first if linkage is out of alignment transmission will not be happy.

[ICHIBANFILIPINO]

My guess is the shifter linkage is out of alignment of you have a bent rod in the shifter linkage and damaged linkage. Based on your last statement saying handful of time it was trying to take of in 3rd,it shouldnt be a guess if it in 3rd but looks like it in first or close clearly I would start with linkage. To the simple stuff first if linkage is out of alignment transmission will not be happy.

Is this going to be internal?

[EuroxS4]

external

[ICHIBANFILIPINO]

external

I mentioned both this option and the slave cylinder to the mechanic that installed the clutch , flywheel and crankshaft seal and he said it sounds like an internal problem, i told him the shift linkage feels off. I'd do this job myself if I had the time and a lift. I've replaced and rebuilt most of the top end of this engine myself already when I snapped a timing belt.

[EuroxS4]

Sometimies having competent mechanic makes all the difference. Not knocking his expertise however some are so hard headed they don't want to listen. Damaged,bent or misaligned linakge can cause your issue. Hope you get it sorted.

[ICHIBANFILIPINO]

Sometimies having competent mechanic makes all the difference. Not knocking his expertise however some are so hard headed they don't want to listen. Damaged,bent or misaligned linakge can cause your issue. Hope you get it sorted.

I am with you on that , that is why I prefer to work all mechanics on all my vehicles. I used to have easy access to a lift but now i am too far from to do the continued work I want. In this case transmission work. Which is a struggle while on the back

[EuroxS4]

I agree this is why I have the luxury of a lift in my home garage just in case.