T56 synchros gong out, or cluch needs a bleeding? Read this
09-12-2006, 07:02 AM
#1
Staging Lane
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Ft. Lauderdale
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
T56 synchros going out, or clutch needs a bleeding? Read this Hi guy's
My tranny grinds going into 3rd and 4th gear at high RPM (5k plus) shifts, but when i double clutch the car (pump the clutch twice quickly before shifting into the next gear) the car shifts perfectly with no problem.
Do you think the car needs to have the clutch bled to remedy this problem? Or is it just the synchros?
Also is GM Synchromesh recommended for this tranny or is the royal purple stuff better?
My tranny grinds going into 3rd and 4th gear at high RPM (5k plus) shifts, but when i double clutch the car (pump the clutch twice quickly before shifting into the next gear) the car shifts perfectly with no problem.
Do you think the car needs to have the clutch bled to remedy this problem? Or is it just the synchros?
Also is GM Synchromesh recommended for this tranny or is the royal purple stuff better?
Last edited by RickC5; 09-12-2006 at 01:22 PM.
09-12-2006, 11:34 AM
#2
Sounds like a possible problem 3/4 shift fork (common problem), or other synchro issue. If it were clutch/hydaulic related you'd see more problems in other gears. Bleeding and flushing out the old fluid couldnt hurt, but I don't think it'll fix your problem.
I'd just use the normal GM stuff, that's what the trans was built for. I don't have first hand experience with royal purple, I'm just not a big believer in "specialty fluids".
I'd just use the normal GM stuff, that's what the trans was built for. I don't have first hand experience with royal purple, I'm just not a big believer in "specialty fluids".
09-12-2006, 01:21 PM
#3
Staging Lane
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Ft. Lauderdale
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
I dont think it could be the forks. The car shifts just fine with no problems at all at anything under 5,500k rpms in any gear. Once i start getting over 5,500 rppm then it starts grinding 3rd and 4th especially. From what I have read on forks, it seems like a problem that is grossly apparant no matter what RPM you are in.
09-12-2006, 03:12 PM
#4
True, plus you'll usually see the trans jump out of 3rd gear. Maybe worn keys on the 3/4 slider or worn blockers or teeth on both gears? When you are "double clutching" what exactly are you doing? Double clutching is usually used when downshifting to spin the lower gear up before you try to engage the slider..... like so...
5th Gear. Clutch In. Neutral. Clutch Out. Rev the Engine. Clutch In. 4th Gear. Clutch Out while the revs are still up.
If you're just giving the clutch two pumps when shifting from 2nd to 3rd and that solves your grind problem it leans a little more towards hydraulics. Especially if you're getting a similar problem getting into 1st or reverse, or its grinding in other gears on high RPM shifts. Hows your fluid level, whats the fluid look like? If you're thinking its hydraulics the most likely culprits would be air in the system (which shouldn't happen without a leak), contaminates in the system (water, rubber, oil etc), a slave that's not strong enough to disenage the pressure plate (maybe your plate is binding at high RPM or your slave isn't going through enough travel, but you'd see this in all gears).
5th Gear. Clutch In. Neutral. Clutch Out. Rev the Engine. Clutch In. 4th Gear. Clutch Out while the revs are still up.
If you're just giving the clutch two pumps when shifting from 2nd to 3rd and that solves your grind problem it leans a little more towards hydraulics. Especially if you're getting a similar problem getting into 1st or reverse, or its grinding in other gears on high RPM shifts. Hows your fluid level, whats the fluid look like? If you're thinking its hydraulics the most likely culprits would be air in the system (which shouldn't happen without a leak), contaminates in the system (water, rubber, oil etc), a slave that's not strong enough to disenage the pressure plate (maybe your plate is binding at high RPM or your slave isn't going through enough travel, but you'd see this in all gears).
09-12-2006, 03:17 PM
#5
Banned
iTrader: (1)
Join Date: Apr 2006
Location: NJ
Posts: 373
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like synchros to me. If it was the shift fork, it wouldn't just grind at high RPM's (if its bent its bent) and double clutching wouldn't help.
The cause is more than likely the synchros, when you shift at higher RPM's and shift quickly, the synchros can't keep up if they are worn out. Meaning they can't synchronize the next gear in time to make for a smooth shift.
Another possibility is the clutch not disengaging quickly enough, in which case you would have to do the drill mod. Many LS1's have this problem. When you are at high RPM's, put the clutch in, wait 5 seconds, and then pound the next gear quickly. If it still grinds, it isn't a clutch disengagement problem, unless the clutch itself isn dragging, which is unlikely if it feels fie otherwise.
The cause is more than likely the synchros, when you shift at higher RPM's and shift quickly, the synchros can't keep up if they are worn out. Meaning they can't synchronize the next gear in time to make for a smooth shift.
Another possibility is the clutch not disengaging quickly enough, in which case you would have to do the drill mod. Many LS1's have this problem. When you are at high RPM's, put the clutch in, wait 5 seconds, and then pound the next gear quickly. If it still grinds, it isn't a clutch disengagement problem, unless the clutch itself isn dragging, which is unlikely if it feels fie otherwise.
09-12-2006, 04:43 PM
#6
Staging Lane
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Ft. Lauderdale
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
nope, Im a VERY fast shifter so it grinds only when im -racing-
I can wait 3 seconds and shift into gear and itll be just fine also im gonna bleed the line today hope it helps!
I can wait 3 seconds and shift into gear and itll be just fine also im gonna bleed the line today hope it helps!
