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View Full Version : Funny grinding sound in first gear, clutch slipping a little under power in 2nd & 3rd



AustinQuattro
12-31-2010, 07:09 AM
So, I took the slushbox out of my 99.5 Avant and put a 5spd from a 2001 A4 1.8T in. After several different pain-in-the-neck problems, I have finally gotten it going, and I was able to drive it to work today. Problem is, in first gear there is a funny sound, not really a grinding, but more like something rubbing against a spinning part (like the flywheel or the driveshaft). It only does it in first gear though. Then in 2nd, 3rd, and 4th the clutch slips a little when I get the boost going. If I had to guess, I'd say I have around 250lbs of torque (1.8T GIAC with Hi-Flow cat). It only happens when the turbo is fully spooled up.

I have only driven it a very small amount, like 3.5 miles total, since completion of the job (and 3 of those miles were on the way to work this morning). I have always been a do-it-myself kind of guy, but I'm thinking I'm going to bring it in to a shop and have them throw it on a lift, put it in first gear, and put ther "stethescope" on it, via a suggestion from a local guru. Does anyone here have any idea what the problem may be? The clutch is nearly brand new, the single-mass light weight flywheel (that does not chatter!!) is nearly new, new throwout bearing, new trans fluid, new rear diff fluid.

Any ideas? The strange sound is the scariest part, because clearly something is not right. The slipping sucks too, but doesn't seem like it will destroy anything as fast. Thanks in advance for any help you may be able to give, or advice you can offer.

snowdogg
12-31-2010, 08:06 AM
Poss bad shift fork?

Scotty@Advanced
12-31-2010, 08:11 AM
So, I took the slushbox out of my 99.5 Avant and put a 5spd from a 2001 A4 1.8T in. After several different pain-in-the-neck problems, I have finally gotten it going, and I was able to drive it to work today. Problem is, in first gear there is a funny sound, not really a grinding, but more like something rubbing against a spinning part (like the flywheel or the driveshaft). It only does it in first gear though. Then in 2nd, 3rd, and 4th the clutch slips a little when I get the boost going. If I had to guess, I'd say I have around 250lbs of torque (1.8T GIAC with Hi-Flow cat). It only happens when the turbo is fully spooled up.

I have only driven it a very small amount, like 3.5 miles total, since completion of the job (and 3 of those miles were on the way to work this morning). I have always been a do-it-myself kind of guy, but I'm thinking I'm going to bring it in to a shop and have them throw it on a lift, put it in first gear, and put ther "stethescope" on it, via a suggestion from a local guru. Does anyone here have any idea what the problem may be? The clutch is nearly brand new, the single-mass light weight flywheel (that does not chatter!!) is nearly new, new throwout bearing, new trans fluid, new rear diff fluid.

Any ideas? The strange sound is the scariest part, because clearly something is not right. The slipping sucks too, but doesn't seem like it will destroy anything as fast. Thanks in advance for any help you may be able to give, or advice you can offer.

Your first gear is toast, you'll have to replace the main shaft and first gear at a minimum. Did you install the clutch used or did you use the flywheel that went with the clutch?

AustinQuattro
12-31-2010, 08:16 AM
Son of a B!+ch! I bought the transmission off a guy here on Audizine, and he even told me that it had been redone 30k miles or so prior, but he didn't know for sure because he didn't own it then. But he said it was doing fine when he had it.

The Clutch, Pressure Plate, and Single-mass LFW all came off of the same car in the junkyard. I lucked out that it was all brand new, almost zero wear on the clutch. But to answer the question, yes it was used, but I utilized the same LFW and Pressure plate.

brettj20
12-31-2010, 09:14 AM
id buy a new clutch and find another tranny. or fix the first gear.

AustinQuattro
12-31-2010, 11:40 AM
Don't know about you, but a new clutch and replacement transmission is not exactly what I would call "cost effective". I've actually got the money, for a change, but not sure that's the most wise decision until I've at least determined what's wrong with the car first. I should have bought one of those Audi Remanufactured 5spd's from ECS when they were selling them. Damn.

So, anyone else have any ideas?

walky_talky20
12-31-2010, 11:58 AM
What did you do about the rear differential? Did you get it from the same car?

somebody5788
12-31-2010, 12:10 PM
The first gear is the most common failure on these transmissions. The teeth wear out or chip and it starts making a whirling kind of noise. As for the clutch. I never go used, it was probably already worn when you put it in or the fly wheel could have been slightly warped. Does it slip in 5th at 30mph? If not are you sure it's slipping?

AustinQuattro
12-31-2010, 01:53 PM
I got the rear diff from Austin VeeDub, which is a European junk yard kind of place. Pretty great actually.

As for first gear, I think it probably is just a messed up gear. Though, it only does it under accelleration in first gear. And as for the transmission, I've driven enough manual trans cars to know when it's slipping...and it has been. Though, not as much now. The clutch that came with the transmission was completely worn out. The clutch I put on the car came from Austin VeeDub with the pressure plate and flywheel. I only bought it because I paid $75 for it, and it was pretty close to brand new. However, when I pull the transmission to either replace it or repair it, I'm going with a new clutch that is uprated.

I haven't put it in 5th gear at 30, but when it's at about 3500RPM in 3rd gear and I stop the gas, the turbo spools up and the RPM's shoot up, but the drivetrain doesn't keep up with it. I let off a little, and it catches back up. I've put almost 30 miles on the car now, and it's not as bad as it was. I think maybe there were some chemicals that got on there while I was doing the swap, and they are burning off. Can't really think of any other explanation. Either way, the sound in first gear is a pain in the ass, but it seems to be working fine, so I'll keep digging for an answer, and I'll start searching for a good trans while I'm at it.

brettj20
12-31-2010, 03:32 PM
drive it till it breaks lol good luck with the car tho.

walky_talky20
12-31-2010, 04:12 PM
Most junkyards have at least some kind of exchange warranty. I know the place I'm getting my 5-speed from has a 6 month warranty (exchange, refund, or repair, their choice) and it's only $150.

adr3naline fix
12-31-2010, 08:01 PM
Well just another opinion to clarify, your first gear is shot for sure. I just replaced my trans for a very similar sound. More of a ticking on my end.

AustinQuattro
01-01-2011, 10:26 PM
Well, I think I'll see about a rebuild. I can probably spend $600-$800 for a rebuild that will have some warranty, and be near new VS. not much less for something that I have no idea what is going on inside. Sucks, but oh well...it is what it is.