multiple drivetrain issues...help or opinions wanted

[DKneble]

A little background on the drivetrain first (99 gsx):
1 yr old stock tranny (launched 3-4 times)
act 2900 clutch
stock rest of drivetrain (70k Miles)

Problem 1:
During decel or coast under 4k rpms a grinding noise can be heard and a slight vibration felt. when above 4k or under the slightest amount of accel the problem goes away. When braking the problem minimizes as well. However when raining the noise and vibration are amplified ten fold. this problem has existed for over a year (had it before i got the new tranny) and was told it by exedy that it was normal clutch decel noise when i had a stg 2 exedy cluth. now i have the act and have done the 6 bolt swap and the problem persists. any takers? Im thinking its the diff.

Problem 2:
Since i installed the act2900 i have launched it a few times. One time that i did the pedal did not fully engage (pop up). Seemed like the clutch engaged, no slipping, but i had to flick the pedal up with my foot then shift to 2nd. That was a couple months ago. Since then no problems until the other day. I did a high speed run (only 155) and when i went to downshift to fourth after slowing down, the clutch pedal stuck again. i managed to pop it up and get it in gear but the pedal felt soft. Now driving today it feels fine. Im thinking it has something to do with heat build up. Any ideas?

Thanks everyone. I know this was alot to read.

Dave

 

[92awddsm]

As for the clutch pedal, have you checked fluid in the clutch master cylinder? Any leaks at the master cylinder or slave cylinder? leaking rubber hose to slave cylinder? Any crankshaft end play? These are usually the most common causes of incomplete pedal return.

Now for the noise, check your driveshaft carrier bearings, transfer case, rear diff, driver side front axle support bearing and wheel bearings. Also, check the torque on the driver axle bracket to block bolts, driveshaft support bolts, and rear universal joint bolts. I cant think of anything that should/would get worse in the rain.