Knackered First Gear - Update: box rebuilt

[MikLSP 0]

I don't know how we missed this when buying the car and can only think that it was from not running it long enough for the gear oil to warm up and make the noise apparent but anyway....

 

I have a nasty rattly noise coming from first gear :(

The car still drives in the gear and the noise stops if you disengage the clutch or when running in any other gear. I'm guessing that the first gear cog is knackered so am I looking at a box rebuild or could there be another explanation?

It's going in for a diagnosis tomorrow but I wondered if anyone has knowledge or experience of something similar?

 

Also would you advise considering a used box from a car that's being broken, of course I don't want to just swap one bad box for another!

 

Cheers,

 

Mik

 

UPDATE:

Having had the gearbox removed and sent away it turns out that my problem was a broken first gear housing and bearing which seized then turned. There were also several knock on effects which I'm afraid I can't remember seeing as I don't know the first thing about gearboxes.

Ultimately the solution was a box rebuild for £420 so if you come across a noise like the one I had, bear this in mind!

[Kevin Bacon 5]

Worn teeth don't rattle, they whine (unless there's teeth missing), and it's unusual for just one gear to do that, especially 1st which is only used for getting the car moving. 2nd gear is on the same shaft. Is that noisy too?

 

Sounds more like a clutch rattle to me.

[Critical_Mass 10]

Worn teeth don't rattle, they whine (unless there's teeth missing), and it's unusual for just one gear to do that, especially 1st which is only used for getting the car moving. 2nd gear is on the same shaft. Is that noisy too?

 

Sounds more like a clutch rattle to me.

 

Hmmm mine started to whine a bit on overrun, sounds like worn teeth by what you've said Kev. But then i cant remember if its always whined, its not loud you may not even notice it if you werent told it was there and like i say only does it on overrun.

 

I was considering changing the oil as i dont think its ever been done, just to see if it improves it. Failing that how much is a gearbox rebuild/refurb?

 

Sorry to thread jack.

[MikLSP 0]

It's definitely a rattle and not a whine or grind. Second gear doesn't make the noise and neither do any others.

 

If it was the clutch would it not make the same noise regardless of which gear is selected? Is there anything I could do to test if it is that?

 

Cheers,

 

Mik

[MikLSP 0]

Just dropped it of at the garage and I paid particular attention to 2nd gear as well. It certainly doesn't make the same rattly noise but it was a little whiny when cold so I guess there's a bit of wear there too.

[Kevin Bacon 5]

Hmmm mine started to whine a bit on overrun, sounds like worn teeth by what you've said Kev. But then i cant remember if its always whined, its not loud you may not even notice it if you werent told it was there and like i say only does it on overrun.

 

I was considering changing the oil as i dont think its ever been done, just to see if it improves it. Failing that how much is a gearbox rebuild/refurb?

 

Standard engine mounts? Uprated gearbox mounts increase whine. Whine on the overrun is normal anyway as the gears are "unloaded". When you accelerate again it should go silent? So long as it doesn't sound like there's sand in the oil, I wouldn't worry about it. VR6 gearboxes go well past 200K if looked after :D

 

It's definitely a rattle and not a whine or grind. Second gear doesn't make the noise and neither do any others.

 

If it was the clutch would it not make the same noise regardless of which gear is selected? Is there anything I could do to test if it is that?

 

I think there could be some misinterpretation of 'rattle' here. The only time I've heard a VR6 gearbox 'rattle' in 1st gear is from clutch judder. The friction plate springs get loose with age and can rattle about if unloaded and loaded aggressively. I know all about that one, I must be on my 6th or 7th clutch now.... It's only noticable in first and reverse usually.

 

I could be wrong though. Let's see what the garage come up with!

[MikLSP 0]

It's basically like a loose rattly noise and occurs while first gear is engaged even if just trundling along and not applying much load. It's hard to describe really but if you image really horrible chain rattle it's that sort of noise but only occurs when moving in first gear.

[Critical_Mass 10]

Hmmm mine started to whine a bit on overrun, sounds like worn teeth by what you've said Kev. But then i cant remember if its always whined, its not loud you may not even notice it if you werent told it was there and like i say only does it on overrun.

 

I was considering changing the oil as i dont think its ever been done, just to see if it improves it. Failing that how much is a gearbox rebuild/refurb?

 

Standard engine mounts? Uprated gearbox mounts increase whine. Whine on the overrun is normal anyway as the gears are "unloaded". When you accelerate again it should go silent? So long as it doesn't sound like there's sand in the oil, I wouldn't worry about it. VR6 gearboxes go well past 200K if looked after :D

 

 

Standard engine mount fitted about 18k ago. Yeah goes silent when accelerating, its purely just on overrun.

 

Well other then this slight whine the gear change is smooth, no other problems at all. Only maybe getting it into first very occasionally - but this is more the circlip as opposed to the gearbox - right?

 

I can here a slight rattle from the clutch when its disengaged, but disappears when i dip the clutch. It had a new clutch at the same time at the mounts so i dunno if the bearing needs changing or anything.

[Kevin Bacon 5]

I can here a slight rattle from the clutch when its disengaged, but disappears when i dip the clutch. It had a new clutch at the same time at the mounts so i dunno if the bearing needs changing or anything.

 

Yep, worn Layshaft bearings. VERY VERY common on these boxes :D It's a box out rebuild job. Most folk put up with it as it doesn't do any harm, or save it for when the clutch / syncros need doing.

[MikLSP 0]

OK, the man at the garage said he didn't hear anything on first gear so he clearly didn't spend enough time checking this out!

I've just got my friend to record the sound on his phone held out of the window. I accelerated a little in first gear which makes a horrible noise, I then dipped the clutch which stops it immediately and then sharply added and removed load before changing into second gear at the end.

 

On this recording it sounds a little different to how I was getting it in the car and is less rattly and more......not even sure how to describe the sound :confused4: but I guess this is more accurate than any description.

 

First Gear Rattle.mp3[/attachment:3nq7mtfa]

Thoughts?

 

Thanks as always,

 

Mik

[MikLSP 0]

Nobody have any thoughts on the noise? :(

[MikLSP 0]

Anyone at all? :shrug:

[Jim 2]

Jesus - that's horrendous. Never heard a noise like that before off a Corrado! :shrug:

[MikLSP 0]

:pale: thanks!

 

I can't understand how we didn't hear it when viewing the car, or even when driving it home :scratch:

 

It's looking the only way to find out what's going on will be to get the box off.

 

Any advice on buying second hand gearboxes and anyone in Lancaster got one they don't need? :lol:

[MikLSP 0]

OK, back onto this...

 

I now know that my first gear is definitely knackered after having it looked at and so I'm looking for advice on the best course of action. My options are:

 

Scavenge parts from a Golf VR6 box to repair 1st (& maybe 2nd) gear.

Buy a used box for a straight swap.

Have the whole thing rebuilt.

 

What would be your advice on these? Is it feasible to use gears from the Golf or are the ratios going to make a mess of things?

 

Mik

[Henny 0]

1st, 2nd and reverse gears are on the same input shaft... if you change one, you've got to change the others... it's only 4th and 5th you can change individually, with 5th being able to be done without stripping the whole box...

 

If you can source a complete gearbox cheaply (should be able to get one for under £250 that's in good nick for any Corrado) I'd go for that, unless you want to spend more and start playing with the box while it's out... ;)

 

Rebuilds start at around £500, but gearbox parts (especially cogs!) can be horribly expensive, especially new from VAG...

[MikLSP 0]

Thanks for the reply :)

 

Yeah I was aware that 1st and 2nd were on the same shaft but didn't know if they could be separated (and didn't realise reverse was attached too actually).

 

My only worry about putting on another used box is ending up swapping one problem for another :S

 

What about using 1st & 2nd from the Golf box? Will I lose a lot of acceleration?

 

Mik

[Henny 0]

1st, 2nd and reverse were the same ratio in all VR6 (12V) gearboxes except for syncro versions... At least, that's what I was told when I had my VR6/G60 hybrid box built... 8)

[MikLSP 0]

I keep finding conflicting information. There are quite a few sources saying they are exactly the same but then other list things like this:

Corrado VR6 2.9:

-1st 3.78

-2nd 2.12

-3rd 1.46

-4th 1.03

-5th 0.84

-final 3.39

 

Golf VR6 2.8:

-1st 3.30

-2nd 1.94

-3rd 1.31

-4th 1.03

-5th 0.84

-final 3.39

 

Are these Golf ratios for the synchro box then perhaps?

 

I think it's probably best to just speak to Vince at Stealth for a conclusive answer ;)

[MikLSP 0]

Hi, just thought I'd throw in an update to this now that things are sorted...

 

Having had the gearbox removed and sent away it turns out that my problem was a broken first gear housing and bearing which seized then turned. There were also several knock on effects which I'm afraid I can't remember seeing as I don't know the first thing about gearboxes.

Ultimately the solution was a box rebuild for £420 so if you come across a noise like the one I had, bear this in mind!

 

Mik :salute: