2nd->3rd Issues
01-25-2015, 10:49 PM
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2nd->3rd Issues I know pretty much nothing about transmissions and wanted to know if this is normal for the 4L60E. Car is a 2001 Firebird Formula.
Basically when I get to the 6200 RPM (Rev Limit set in tune) in 2nd gear, I have to let off the gas for it to shift or it'll hit the rev limiter. Is this normal operation?
Thanks!
Basically when I get to the 6200 RPM (Rev Limit set in tune) in 2nd gear, I have to let off the gas for it to shift or it'll hit the rev limiter. Is this normal operation?
Thanks!
Last edited by JordanRN; 01-25-2015 at 10:59 PM.
01-26-2015, 07:28 AM
#2
This could be a couple of things, but If I had to take a stab at it, I would say the 3/4 clutches are done for. This is not normal operation. Perhaps a couple of the more transmission oriented people will hop in with their .02.
-Brian
-Brian
01-26-2015, 08:57 AM
#3
If it's not the tune it is most likely the clutches. Has the car previously been fine with the same tune and is this something new?
Does this happen on D (3rd) or OD (4th) or both? When mine was going out it only did it in D and install of a Sonax HD 2-3 shift valve covered it up for the rest of the race season for me. Upon dissection the 3-4 clutches were worn down to the metal and coned but the valve was helping enough it wasn't slipping.
You can also try an extra half qt of fluid if it's not already overfull.
EDIT: and also note it is not really a good idea to lift off the throttle for a WOT shift. If the problem cannot be corrected do not rely on that, be easy with it until the transmission can be rebuilt. A rebuild costs significantly more if hard parts break.
Does this happen on D (3rd) or OD (4th) or both? When mine was going out it only did it in D and install of a Sonax HD 2-3 shift valve covered it up for the rest of the race season for me. Upon dissection the 3-4 clutches were worn down to the metal and coned but the valve was helping enough it wasn't slipping.
You can also try an extra half qt of fluid if it's not already overfull.
EDIT: and also note it is not really a good idea to lift off the throttle for a WOT shift. If the problem cannot be corrected do not rely on that, be easy with it until the transmission can be rebuilt. A rebuild costs significantly more if hard parts break.
01-26-2015, 09:58 AM
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If it's not the tune it is most likely the clutches. Has the car previously been fine with the same tune and is this something new?
Does this happen on D (3rd) or OD (4th) or both? When mine was going out it only did it in D and install of a Sonax HD 2-3 shift valve covered it up for the rest of the race season for me. Upon dissection the 3-4 clutches were worn down to the metal and coned but the valve was helping enough it wasn't slipping.
You can also try an extra half qt of fluid if it's not already overfull.
EDIT: and also note it is not really a good idea to lift off the throttle for a WOT shift. If the problem cannot be corrected do not rely on that, be easy with it until the transmission can be rebuilt. A rebuild costs significantly more if hard parts break.
Does this happen on D (3rd) or OD (4th) or both? When mine was going out it only did it in D and install of a Sonax HD 2-3 shift valve covered it up for the rest of the race season for me. Upon dissection the 3-4 clutches were worn down to the metal and coned but the valve was helping enough it wasn't slipping.
You can also try an extra half qt of fluid if it's not already overfull.
EDIT: and also note it is not really a good idea to lift off the throttle for a WOT shift. If the problem cannot be corrected do not rely on that, be easy with it until the transmission can be rebuilt. A rebuild costs significantly more if hard parts break.
Never noticed it before I got it tuned. Don't have any issues when I'm driving it normal or from 3>4 WOT. I'll check in the tune and keep posted.
01-26-2015, 12:36 PM
#6
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You should have mentioned right the "Never noticed it before I got it tuned".
Ask your tuner to reduce the "WOT Shift MPH" by 5% (it is not a critical number) and make sure the "WOT Shift MPH" values match the 100% throttle numbers in the partial throttle shift table.
Or bump your redline up a bit as 6200 seems very conservative.
Of course your 3/4 clutch might also be slipping, but changing the tune is likely simpler than rebuilding the trans.
Ask your tuner to reduce the "WOT Shift MPH" by 5% (it is not a critical number) and make sure the "WOT Shift MPH" values match the 100% throttle numbers in the partial throttle shift table.
Or bump your redline up a bit as 6200 seems very conservative.
Of course your 3/4 clutch might also be slipping, but changing the tune is likely simpler than rebuilding the trans.