Gto t56 gear noise... Help!
10-18-2013, 11:19 PM
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Gto t56 gear noise... Help! Any help would be greatly appreciated!
My 2005 GTO has 70k miles now, bought it with 35k 3 years ago. It never felt like it shifted smoothly, probably prior abuse. I haven't done anything to the clutch hydraulics or fluid, probably original clutch. I ran it out on the highway a few weeks ago in 4th, 140 mph, tried to shift to 5th, wouldn't go... Went to 6th, tried 5th later at a more sane speed and it went.
It's done that before, unhappy going into 5th. Now going from neutral to 1st sometimes won't go until I go to 2nd first, then into 1st.
Also, the big symptom now, the trans is making a hell of a gear whine at all speeds, noticeable predominantly in 3rd-6th, and loudest in 3rd, 5th, and 6th. The noise sounds like a reverse gear sound, only much much higher pitch (40-80 mph). The pitch drops slightly with each upshift, but not as much as the revs, pitch seems to rise more in proportion to vehicle speed. It seems louder after the trans warms up. The noise drops in pitch slightly when the clutch is pushed in when traveling at speed, and shifting to neutral makes no difference. When shifting between gears I can hear the gears spinning down on upshifts and spinning up on downshifts.
The noise is not the diff... It has a different whine it's had since I got the car.
It has gotten louder over the past couple weeks and now I'm finally at a point where tomorrow I have time to do some diagnosis.
Anyone want to take a crack at what's wrong? I'm going to change the fluid tomorrow and perhaps bleed the clutch. I wish I could find a definitive reference on what fluid to put back in.
...after doing some searching , I have definitely gotten a soft clutch pedal after shifting... So I need a new clutch for one thing, I think.
My 2005 GTO has 70k miles now, bought it with 35k 3 years ago. It never felt like it shifted smoothly, probably prior abuse. I haven't done anything to the clutch hydraulics or fluid, probably original clutch. I ran it out on the highway a few weeks ago in 4th, 140 mph, tried to shift to 5th, wouldn't go... Went to 6th, tried 5th later at a more sane speed and it went.
It's done that before, unhappy going into 5th. Now going from neutral to 1st sometimes won't go until I go to 2nd first, then into 1st.
Also, the big symptom now, the trans is making a hell of a gear whine at all speeds, noticeable predominantly in 3rd-6th, and loudest in 3rd, 5th, and 6th. The noise sounds like a reverse gear sound, only much much higher pitch (40-80 mph). The pitch drops slightly with each upshift, but not as much as the revs, pitch seems to rise more in proportion to vehicle speed. It seems louder after the trans warms up. The noise drops in pitch slightly when the clutch is pushed in when traveling at speed, and shifting to neutral makes no difference. When shifting between gears I can hear the gears spinning down on upshifts and spinning up on downshifts.
The noise is not the diff... It has a different whine it's had since I got the car.
It has gotten louder over the past couple weeks and now I'm finally at a point where tomorrow I have time to do some diagnosis.
Anyone want to take a crack at what's wrong? I'm going to change the fluid tomorrow and perhaps bleed the clutch. I wish I could find a definitive reference on what fluid to put back in.
...after doing some searching , I have definitely gotten a soft clutch pedal after shifting... So I need a new clutch for one thing, I think.
10-18-2013, 11:34 PM
#2
Clearly theres something internally damaged. Most likely bearings. But if you're having trouble going into gears, then either blocking rings or synchros are worn/broken. Regardless, it needs to be pulled and gone through. Rebuilding a t56 PROPERLY costs more than just buying an RPM built transmission and sending yours as a core. I can almost promise you at least 4 of the 7 gears (1-6,R) have excessive wear to the gear teeth. Even the sliders may have damage to them. While the trans is out, might as well put a clutch and definitely a slave cylinder/throwout bearing with a Tick Speed Bleeder.
10-19-2013, 10:01 AM
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I really think the going into gear issue is a clutch pressure plate problem I read about here: https://ls1tech.com/forums/17306065-post10.html
The noise, yeah, definitely internal... I guess I need to figure out what is the most economical solution. The motor is not modded, just exhaust.
Thanks for the reply, luigiandme
The noise, yeah, definitely internal... I guess I need to figure out what is the most economical solution. The motor is not modded, just exhaust.
Thanks for the reply, luigiandme
10-20-2013, 09:47 PM
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Changed the fluid yesterday, man it does come out fast! It was pretty black in color but didn't smell bad. I ran a magnet through it and there was no ferrous metal. There may have been some fine particles of non-ferrous metal, looks like the texture of cream in coffee when you stir it around. New cheap dex III and it still makes the same sound and shifts the same (which isn't horrible anyway). I know it's got to come out, now it's time to figure out what's the best and most economical fix.
