Dangerwillrbnsn

Hello again fellas.

I wanted to catch your feedback on this one. I have a rattle that only exists in 1st gear when I release the clutch and I'm moving. I can feel it at the base of the shifter. It is quit loud.

If I'm sitting still, no rattle. I can engage 1st with the clutch in, no rattle. But as soon as I get rolling - under light OR heavy acceleration the rattle starts.

I met up with LUCKYJACKASS last night, and he suggested you all might know rather quickly what's up.

Thanks I have advance
DWR

szabon

I don't really know, but did you check your shift linkage? Maybe something's loose in there.

Dangerwillrbnsn

Seems like it may be in the linkage. I just picked up a 944 workshop manual to look at. Ill see something, hopefully. Until then, ill stay open to your input.

Dangerwillrbnsn

The FSM didn't shoe anything helpful. I made a video of the noise
Maybe someone out there knows what's up. I have reserved a lift for Friday night to have a look.


http://static.photobucket.com/player...-36-00_687.mp4

VirginiaF1

Great video for analysis..
From my ear, I can't get over hearing exhaust rattle that matches revs, ya?

kachunk

Torque tube bearing is shot?

http://forums.pelicanparts.com/porsc...ine-noise.html

My car was making a similar noise specifically when clutching in first gear. It sounded like a heat shield kind of rattle. The sound went away when the clutch was fully engaged and the engine speed increased. The video in the link is with the transmission removed, and no load on the drivetrain, so it sounds different, but my car was making similar noises on to yours. My front torque tube bearing was completely toasted.
That's just my experience on my car. If your clutch feels fine, it could be a torque tube bearing.

TexasRider

I have a NOISE too and posted on it sometime ago. I dont think there were any replies - but mine is RPM specific at about 2200 rpm or so.

It doesnt happen when past those revs and not before. Clutch is engaged and in gear. By 2400 or 2500 it is gone. Maybe even 2300. In any event it does not stay even if I hold 2200 rpm. Bothersome.

My clutch works great and I got the car up on the rack and wiggled and tried to find ANYTHING loose. If I did not know better I would say it is an exhaust hanger rattle, because my sound is a rattle. But nothing is loose and no rubber worn. But it defintely sounds like it from that left rear area to me on my 951.

If it is a rattling sound that goes away like mine does, I am inclined to think that maybe some of the guts in the catalytic converter are loose and rattling. That is all I can come up with on mine.

If it is more of a continuous sound or a screech then it makes sense that a bearing.

Dangerwillrbnsn

I kinda thought the same. I'll have it on a rack tomorrow to look around some. I really hope it's something as small as an exhaust rattle, but it's not likely... it goes away instantly with clutch in, or when shifted to any gear other than 1st.

I sure hope not. It may be... although my noise comes in OPPOSITE of yours. My noise only comes on when the clutch pedal is released and in 1st gear. Noise is gone in any other gear, or in any other clutch position.


Interesting thoughts. I'll pull the exhaust off tomorrow and give the catalytic a shake. My noise, unfortunately is at ALL RPM ranges in 1st gear only. Goes away in any other gear, so I'm hopeful that my bearings are good.

Dangerwillrbnsn

Well, I spent the day in by buddies shop playing with the car. I have my hands full with this one. It's true - every 951 is a $10k minimum car.

1. The rattling noise seems to be coming straight from the trans. I'm hearing it in the cabin near the shifter, so apparently the noise is just traveling. I drained the old (really nasty and dark) trans fluid and replaced it with a nice 75/90 synthetic. It did not help. I really hope not to have to swap the trans, so if anyone has a solid idea of what else it may be - please feel free to share.

2. Axle bolts were loose and almost falling out of the passenger side at the trans. Tightened them up, with no change in the rattle (but at least they wont be falling out or shearing off).

3. Pressure tested/smoke tested the intake tract. Found a few leaks, and replaced the offending hoses. The result here was gaining another 5" of vacuum! Sweet, I now idle at 13-14" of vac. Not good, but certainly better than the old 8" I was getting.

4. Installed my LC-1 wideband. Well, half installed. I ran out of time. The wiring is still a mess, and I have to permanently mount it all - but I got it operational. Initial results showed a horrible rich idle AFR at something to the tune of 8.5! I know the PO messed with the AFM clock spring, so I set to work getting it back to right. Final results, I now have a perfect 14.7 at idle, cruise at 13.8 - 14.2, low boost at 11.8-13.1, and WOT at 10.5-10.9.

5. Noted SEVERAL leaks. Power steering rack, power steering lines, possible rear main, and a few other minors. No repairs made

6. Noted surface rust in the undercarriage. No repairs made.

7. Topped up oil, as it was AT LEAST 2 quarts low. I must be burning oil... but at only 120k?

8. My mind is going blank... but there was more. I'm sure you'll hear back from me with a new issue - but at least for now I feel like it's SAFE to drive the car now. Thanks for all your help, fellas. It's great to be in the mix with knowledgeable folks.

Hollywood D

Have you tried the old screwdriver trick? Use a screwdriver, or other metal pole and put it to the trans and your ear to the other end. If it is coming from the trans you may be able to isolate it a little bit more.

Dangerwillrbnsn

No, I haven't. It's tricky... I neglected to mention that this rattling noise is much more pronounced when the car is on the ground and actually driving. When it was on the lift, the noise was much less audible.

I should have tried using his mechanics stethoscope. Crap.

Hollywood D

Well worst case scenario you can always try and find a parts car and get the transmission out of it. I then they go for around $200, for an N/A transmission at least. I think the turbos have different gear ratios.

Dangerwillrbnsn

Good call. There are two NA's in the local yard right now. Transmission's there are only $180. Any reason I can't run a trans from one of them? I hear the ring and pinion is smaller on the NA's. Can I swap the ring and pinion from mine into the NA?

Hollywood D

That I have no idea about. Somebody will tho, try posting in the 951 section maybe.

Fernando01

Hi, we had a 1989 Porsche 944, which my mom bought brand new from the dealer at that time. It always made this noise in first gear, Right up until 2200 RPM or so. At the time, the dealer confirmed that this was “normal“ and back then there was no Internet or car forums like this to consult, so we took it at face value.

We owned the car for about five years, then sold it, and never had a transmission issue, other than that weird noise in 1st gear.