fresh trans rebuild, downshift grinding 2nd intermittently.
03-03-2011, 08:34 PM
#1
fresh trans rebuild, downshift grinding 2nd intermittently. 04 cts-v
got the tranny in the car and everything is great, aside from the occasional grind when I downshift into 2nd only.
It's not like a grind then shift, it's a grind, and I can't get in the gear. I could almost pull it into 2nd gear when I was sitting idle without pressing the clutch in.
Now, here's a few things I think it could be, please let me know what you think.
1. When I pulled the transmission, I disconnected the slave from the master, and lost no fluid as it's all air-tight. Is it possible it sucked air into the system and it's trapped in the slave?
2. I don't remember if I tightened both bolts on the shifter, and while I'm sort of thinking I did, could I have forgotten to tighten one and caused slop in the shifter? Would that cause a grind?
These are all fresh syncros, about 150 miles on the trans, and I'm afraid of ruining it.
it did it for a small period of time yesterday, and like 10 minutes today on the way home, then it got magically better.
the car is loaded with royal purple max atf.
got the tranny in the car and everything is great, aside from the occasional grind when I downshift into 2nd only.
It's not like a grind then shift, it's a grind, and I can't get in the gear. I could almost pull it into 2nd gear when I was sitting idle without pressing the clutch in.
Now, here's a few things I think it could be, please let me know what you think.
1. When I pulled the transmission, I disconnected the slave from the master, and lost no fluid as it's all air-tight. Is it possible it sucked air into the system and it's trapped in the slave?
2. I don't remember if I tightened both bolts on the shifter, and while I'm sort of thinking I did, could I have forgotten to tighten one and caused slop in the shifter? Would that cause a grind?
These are all fresh syncros, about 150 miles on the trans, and I'm afraid of ruining it.
it did it for a small period of time yesterday, and like 10 minutes today on the way home, then it got magically better.
the car is loaded with royal purple max atf.
03-05-2011, 12:03 AM
#5
Nothing guys? I got a lot of air out of the system, and the pedal felt better, but it still feels notchy and it did it again tonight.
Its not really so much a grind as when I try to put it in second it vibrates makes noise and won't let me get in gear.
Its not really so much a grind as when I try to put it in second it vibrates makes noise and won't let me get in gear.
03-05-2011, 06:59 AM
#6
I'd take it back to the place where the rebuild was done and have them check it out again. Did they give you give you break-in instructions? I ussualy recommend a minimum of 500mi break-in followed by a fluid flush.. No downshifting or hard shifting during those 500mi.. The friction material on the blockers isn't so different from clutches and brake pads, abuse them early and they'll wear quickly.
Billet keys will also give a "notchy" feel while they are first being broken in, and that can last for 1000mi or more.
Billet keys will also give a "notchy" feel while they are first being broken in, and that can last for 1000mi or more.
03-05-2011, 11:12 AM
#7
Thanks Mike.
It's not like 4th to 2nd downshifting for a powerful street race. I'm talking going from 45 mph to 15 and needing to trek a hill.
I've bled the clutch twice today. I tried a different method someone told me, which was cracking the bleeder, pressing the clutch, closing the bleeder, and pumping it up, all while keeping an eye on the fluid level in the res. I will say I put a lot more fluid back in than I let out of the bleeder. I think the way I bled it previously got some air out, but let a lot of air in. I had someone hold the clutch down, cracked the bleeder, then closed it and had him pump the clutch until there was a pedal again.
After I bled it each way, the shifter felt way more loose, and good all around. Lost a lot of it's notchiness, and it feels a lot more precise.
Is it possible if I keep with bleeding it that it'll eventually get a bit better for good?
It's not like 4th to 2nd downshifting for a powerful street race. I'm talking going from 45 mph to 15 and needing to trek a hill.
I've bled the clutch twice today. I tried a different method someone told me, which was cracking the bleeder, pressing the clutch, closing the bleeder, and pumping it up, all while keeping an eye on the fluid level in the res. I will say I put a lot more fluid back in than I let out of the bleeder. I think the way I bled it previously got some air out, but let a lot of air in. I had someone hold the clutch down, cracked the bleeder, then closed it and had him pump the clutch until there was a pedal again.
After I bled it each way, the shifter felt way more loose, and good all around. Lost a lot of it's notchiness, and it feels a lot more precise.
Is it possible if I keep with bleeding it that it'll eventually get a bit better for good?
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03-05-2011, 05:04 PM
#8
Just talked to the guy who did the work. He said 2nd gear is the first gear on the input shaft, so if there's any play in my input shaft, that would explain why 2nd is behaving that way. He said it could either be a bad tip on the input shaft, or a bad pilot bearing, which I replaced when I did the clutch.
He asked me if there's any vibration in my clutch pedal, to which I responded yes, and he said it sounds like it could be an input shaft issue. Does anyone agree?
The ******* thing started occasionally grinding on the 1-2 shift now. I'm gonna not drive it for as long as I can until he can look at the car. I'm at a loss for words right now.
He asked me if there's any vibration in my clutch pedal, to which I responded yes, and he said it sounds like it could be an input shaft issue. Does anyone agree?
The ******* thing started occasionally grinding on the 1-2 shift now. I'm gonna not drive it for as long as I can until he can look at the car. I'm at a loss for words right now.
Last edited by RADEoN; 03-05-2011 at 05:37 PM.
03-05-2011, 06:21 PM
#9
Just talked to the guy who did the work. He said 2nd gear is the first gear on the input shaft, so if there's any play in my input shaft, that would explain why 2nd is behaving that way. He said it could either be a bad tip on the input shaft, or a bad pilot bearing, which I replaced when I did the clutch.
Just about the only thing that affect 2nd adversely is a worn blocker or some sort of mis-assembly.
03-05-2011, 06:30 PM
#10
so what would cause my car to do what it's doing?
here's a shitty video of what's going on with the downshift:
http://www.youtube.com/watch?v=2sFRjlnoDPc
* 1st and 2nd are often notchy going in and out of gear.
* When I bleed my clutch, the pedal gets very loose and feels good for a bit.
* To get into a gear, I sometimes have to press the clutch the whole way, go towards the gear, and get jammed up. I let off the clutch about an inch, and it slides right in.
* Sometimes (more often than not) when I'm shifting, and press my clutch, I get a vibration that is felt in my entire leg.
oh, and my car started REEKING of transmission fluid yesterday.
also, do you think it's possible my synchro could survive this?
here's a shitty video of what's going on with the downshift:
http://www.youtube.com/watch?v=2sFRjlnoDPc
* 1st and 2nd are often notchy going in and out of gear.
* When I bleed my clutch, the pedal gets very loose and feels good for a bit.
* To get into a gear, I sometimes have to press the clutch the whole way, go towards the gear, and get jammed up. I let off the clutch about an inch, and it slides right in.
* Sometimes (more often than not) when I'm shifting, and press my clutch, I get a vibration that is felt in my entire leg.
oh, and my car started REEKING of transmission fluid yesterday.
also, do you think it's possible my synchro could survive this?
Last edited by RADEoN; 03-05-2011 at 06:41 PM.
03-05-2011, 07:13 PM
#11
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What was the original reason the trans was rebuilt for and what parts specifically were changed inside the trans and if anything was replaced clutch or hydraulic wise?
03-05-2011, 07:14 PM
#12
The clutch release is clearly at issue. Keep looking for leaks under-dash and under-car. I like to bleed this way, once the fluid is clean and clear: https://ls1tech.com/forums/13837919-post3.html
If it's absolutely good release (hold clutch pedal, rev car to 4k; car doesn't move at all on flat surface) and 2nd still grinds, take the trans out and back to the builder.
If it's absolutely good release (hold clutch pedal, rev car to 4k; car doesn't move at all on flat surface) and 2nd still grinds, take the trans out and back to the builder.
03-05-2011, 07:48 PM
#13
Me and PISNUOFF put an LS7 clutch, slave, flywheel, pressure plate, and a stock CTS-V master cylinder in. So pretty much the entire clutch system.
I was having an issue with putting the car in 1st. I could get it in, but it would grind.
http://www.youtube.com/watch?v=04NYbCM6DiU
http://www.youtube.com/watch?v=U5VTyxB5zaM
I noticed the slave cylinder was leaking when I pulled the transmission, and I had a new one sent and installed it.
I'm thinking about putting my bleeder extension into a jar of brake fluid, and having someone monitor my brake fluid res level, and pumping the **** out of the pedal for about an hour.
03-06-2011, 10:00 AM
#17
I've seen issues with some shops that don't know that the new GM triple/double cone synchros are different than the older F-body ones and will replace them with the older incorrect part.
If you were having issues with all gears, you typically look at the clutch or hydraulics. Issues with a single gear usually point to something internal of the transmission.