After installing an F23 and driving about 1200 km problem free, my car has developed a very loud rattle. Trans and engine seem to work fine other than the noise.
Cradle has been dropped and tranny sent to a trans shop, and they don't see anything wrong with it. Clutch, HTOB, Pressure plate seem to be fine. Sound seems to change (but not disappear) when clutch is depressed.
To me it sounds like perhaps a broken lifter, but then clutch should not affect it... Really stuck and frustrated.
That almost sounds like the noise the MU9 6 speed input shaft bearing makes if there isn't enough pressure on the pressure plate. It makes a sound like rocks grinding. A lot of people got this problem on the early transmission. I had that problem and put a spacer behind the throw bearing. It worked for me despite the bearing always riding the pressure plate fingers. I'm not saying that, that is your problem.
From Wikipedia (may not be exactly applicable, but it could be.)
Rattling / Grinding On 28 January 2002, General Motors released a Technical Service Bulletin (TSB #02-07-29-001) addressing a "Grinding/Rattle Type Noise Coming From Transmission". The TSB was intended for the following GM vehicles equipped with the GM Quad 4 (RPO LD9) Engine and Getrag M86/M94 5-Speed Transmissions:
2000–2002 Chevrolet Cavalier 2000–2001 Oldsmobile Alero 2000–2002 Pontiac Sunfire 2000–2001 Pontiac Grand Am The bulletin continued to explain that there are actually two distinguishable noises which have two very different remedies.
There are two separate noises. Follow the diagnostic procedures listed below to determine which noise the vehicle has and perform the outlined repair.
Noise 1: This is a very distinct noise that is usually much louder than the second noise that can be associated with this transmission. If the vehicle is not making any noise when trying to verify the condition, it can be induced by making several tight left hand circles with the vehicle at normal operating temperature. Making a sharp right hand turn will usually stop the noise. While the noise is occurring, in order to distinguish between the two noises, you can press lightly on the clutch pedal without releasing the clutch and the noise will NOT go away or change. As a second diagnostic aid, while the vehicle is making the noise, shift to third gear and the noise will stop.
Noise 2: This noise, commonly referred to as gear rattle, can be induced by lugging the engine in any gear, but is usually most noticeable in first or second gear. While the noise is occurring, if you press lightly on the clutch pedal without releasing the clutch, the noise will be reduced or eliminated. General Motors provided a fix for "Noise #1" but stated that "Noise #2" was a characteristic of any car equipped with a manual transmission and that a similar noise could be repeated by lugging the engine. The remedy for "Noise #1" was to overfill the transmission with Saturn Manual Transmission Lubricant from the stock 1.8 quarts to 2.6 quarts. Although this seemed to work for many customers, many other complaints still surfaced and in 2003 General Motors released another TSB urging customers that still have the rattling noise in their transmissions should bring their vehicles in to their nearest General Motors affiliated dealer for a more complex fix.[citation needed] This time, GM Technicians had concluded that gears one and two required additional thrust loads and proceeded to install a wave washer between the blocking ring and speed gears for gears three and four. This indeed fixed the rattle issue once and for all, but has more recently been lamented in many online communities as causing a bigger problem than it solves, as many customers that received this fix reported third and fourth gears grinding from time to time while shifting. Afterwards, many owners of these vehicles have concluded that leaving the transmission alone was for the best, as the rattling noise has been proven to be harmless.
Loose flywheel? Maybe, but that would cause the motor to stall out with the vibrations/shocks making the knock detectors activate at idle. (Had this happen on my 3800) Does the sound go away above idle? In the 2000rpm or above range? Could be a worn timing chain? The slow engine speed at idle accentuates the noise of the valve train; cam jumps and snaps up the looseness in the chain. All the race cars that have high lift cams, etc... sound dreadfull at idle! My timing chain is a little worn and my car sounds like sh1t at idle😉, not quite as bad as yours, but similar.
The F23 in my Gran Damn makes a similar noise, not as loud, but it's the same kinda rhythm, for lack of a better term. did you check the flywheel bolts already? Mine has made the noise since install, and has about 1000 miles or so on it, so I just figured it was just a noisy transmission.
I was able to reach under the car and grip the flywheel, it didn't have any apparent play, so I'm interested in learning what your transmission shop says.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
[This message has been edited by ericjon262 (edited 03-02-2023).]
so, today, I dumped the ATF out of the Gran Damn and put synchromesh in, the noises are now WAY quieter, I highly recommend it, but only time will tell if it stays quieter, or the transmission doesn't totally eat itself.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
