Hello all, Just picked up my second BMW last week. I had the 318 and now got the 325- a world of difference but to my point- I notice sometimes when I come to a full stop and put the stick in 1st to start again I hear and feel a slight "thump"..It wont do it all the time either. To fully describe the scenario- when I press clutch in there is no noise yet. As soon as the shifter hits going into 1st (and even sometimes i can notice in second gear as well) i can hear the "thump" from underneath..Almost as if you were to get under your car and hit it with your fist would produce the sound i hear. I have owned several manual cars and am familiar with normal sounds and this isnt anything I have heard before. Anyone else have this problem and have any suggestions as to diagnose? It doesnt seem to affect performance, but I need everything to be perfect and it annoys me..I will check the linkage and maybe change out the tranny fluid but im really interested to see if this has happened to anyone else.. Thanks guys
Shifting Noise
- Thread starter 93 325i
- Start date
I actually have the same exact problem. I baught my car about a month ago and i can hear a thumping noise when shifting to first and 2nd gear. The clutch seems like it engages where it should in the middle, but the thumping has me a little concerned. Also, if your driving at a steady speed and slightly press the clutch (not to disengage it, only about 1-2 inches.) can you feel like some sort of vibrating on your foot. I dont know if this is normal but my dad pointeed these things out when driving my car. I had never experianced this with other manual tranny cars
The thump you are hearing is just the slack in the rear half shafts and differential being taken up when you engage a gear. When you are sitting with the engine running in neutral, the layshaft in the transmission is rotating at engine speed. When you push the clutch pedal, even though you have disconnected the transmission from the crankshaft, there is still inertia in the clutch disc and the transmission internals, so the layshaft continues to rotate for a while. When you then engage first gear, the first gear synchronizer has to stop the layshaft from rotating in order to engage the gear. When this happens, it puts a momentary torque on the driveshaft, causing any drivetrain play in the ujoints, differential, and halfshafts to be taken up abruptly, producing the "thump."
Try this - have the car sitting in a parking spot with the engine running, the transmission in neutral, and your foot OFF of the clutch, just like when sitting at a traffic light. Push the clutch in like you are going to engage first gear, but don't shift to first yet. Wait about 10-15 seconds, and then engage first gear. During this time, the clutch disc and transmission layshaft will slow down and eventually stop rotating. I guarantee that you won't hear the thump when you engage the gear.
Hernandez - the vibrating in your foot while only pressing the clutch a short ways is the result of the throwout bearing lightly contacting the pressure plate "fingers." It's normal. But, don't drive around pressing the clutch an inch or two - that will wear out both the clutch and the throwout bearing.
Try this - have the car sitting in a parking spot with the engine running, the transmission in neutral, and your foot OFF of the clutch, just like when sitting at a traffic light. Push the clutch in like you are going to engage first gear, but don't shift to first yet. Wait about 10-15 seconds, and then engage first gear. During this time, the clutch disc and transmission layshaft will slow down and eventually stop rotating. I guarantee that you won't hear the thump when you engage the gear.
Hernandez - the vibrating in your foot while only pressing the clutch a short ways is the result of the throwout bearing lightly contacting the pressure plate "fingers." It's normal. But, don't drive around pressing the clutch an inch or two - that will wear out both the clutch and the throwout bearing.
The slight "hump" when selecting gear is normal thing in manual gearbox, it's just gear engaging, just try to select the gear smoother to avoid it (not slower - smoother).
To second poster: you are riding the clutch so vibration is normal in this case, DO NOT ever do it, once engaged leave the cluch pedal alone.
To second poster: you are riding the clutch so vibration is normal in this case, DO NOT ever do it, once engaged leave the cluch pedal alone.
![[scratch]](/images/smilies/icon_smile_headscratch.gif "Head Scratch [scratch]"){kind=icon}
Congrats on your new car. 93 325i is a good choice, but then I am biased.
I believe I have a similar sound with mine as well. I haven't done a complete troubleshooting session on it yet. I know I need to do some of the shift linkage bushings, but I was just going to replace them all when I do a short shift kit. I am also planning on replacing the tranny and diff fluids. My car feels like there is a little bit of driverline lash at times, so I was going to replace the diff mounts while I'm at it.
Wish I had something helpful to tell you...
-Joe
EDIT: It looks like some helpful info got posted. Good stuff there!
I believe I have a similar sound with mine as well. I haven't done a complete troubleshooting session on it yet. I know I need to do some of the shift linkage bushings, but I was just going to replace them all when I do a short shift kit. I am also planning on replacing the tranny and diff fluids. My car feels like there is a little bit of driverline lash at times, so I was going to replace the diff mounts while I'm at it.
Wish I had something helpful to tell you...
-Joe
EDIT: It looks like some helpful info got posted. Good stuff there!
