rattle/knock in 2nd gear ONLY

grimreaper

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Jul 2, 2008
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Im scratching my head here... 89 7mgte 5 speed r-154. fresh mt90, shifter bushings, diff fluid. Re tq'd subframe bolts about 3-4 months ago.
For the past 8 months ive noticed this what sounds like a knock or heavy rattle from 2nd gear only.
-free rev = no noise
-1,3,4,5= no noise.
-fully warmed up= no noise
- First drive of the day (cold)= knocking/rattle noise until warm (gets quieter until its gone)
-happens between 2200-2500rpms only.
-oil psi is 60-70 usually as its only when cold (no twitches or spikes) through rpm range.
-no vibrations felt in shifter or pedals during the noise

I thought it was speed related (about 25mph) and kept it in first or short shifted 3rd but couldnt replicate the noise. If i crawl through the rpms in 2nd - no noise. I can replicated it easily but only for the first 10 mintues (or so) of drive time (usually by the time the cars wamred up the noise is gone.)

anybody seen this before? any suggestions or plausible causes?
 

grimreaper

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Jul 2, 2008
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drive shaft is in line and all flange bolts tight. Nothing behind the trans is loose. Its coming from the drivers seat forward unless the noise is traveling.

driver side mount *looks* ok but ill get a jack under the trans/motor and lift it a bit to see for sure this weekend.
the colder it is the louder or heavier the sound is. Almost like oil isnt getting to a bearing in the trans or something until the gear oil warms a bit. Never messed with the trans so im lost on whats in there... or if thats even realistic.

anything?
 
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grimreaper

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driver side motor mount is about half torn through... passenger side is in two pieces. Really amazed as there isnt much vibration, or ive gotten used to what small vibrations this issue is causing. 2jz mounts coming this week and ill see if the noise continues...
 

grimreaper

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Jul 2, 2008
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new mounts in. they raised the motor up to the point that the fan was hitting the custom shroud top.

my findings are that the previous owner built the shroud around the fans location with the old mounts. The old mounts let the motor sit a bit lower but once they ripped in two the tq over on the motor let the fan contact the shroud lightly. Iv had other weird and very light noises before when reved hard that seem to back up the fan and shroud contacting each other.

Guess once the fan clutch locked up the contact wasnt enough to make the noise rather it just forced the fan to rotate even with the light contact on the shroud. fan blades show wear at the very tips as well as the top of the shroud... lesson? build the shroud with good mounts or keep the stock shroud. New shroud coming this week, the cars been moderatly costly this month...

on a side note.. FUCKING AMAZING what the 7m feels like when properly secured. Id have to say the mounts have been torn and busted since ive owned the car. Never been this smooth and who knew attaching that iron hunk to the frame would make take offs and corners more in unison with the cars movement... I serously thought people were screwed in the head to think the 7m was smooth...