please advide on problem..tranny/converter?
Thread Starter
Burning Brakes
Joined: Jun 2006
Posts: 1,164
Likes: 1
From: SOCAL CA
the lines on the converter were clogged?
they cant clean the converter yank has to cut it open, when my trans went from a tsb then the tech screwed it up, i had them put the new trans in and sent the converter back to vig, i didnt even put it in because the trans was running hot, they found out the lines were clogged so they replaced all four, that means when the trans went they never cleaned the lines or did a flow test then the car ran that way for 1000 miles when they put the new lines on they never droped the pan to change the filter, gm is some crappy service
Melting Slicks
Joined: Jul 2007
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From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
Race Director
Joined: Mar 2005
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From: Southampton NJ
i know the trans needs exspert tuning or it doesnt get converter lockup and their is a tsb for mis machined case causing metal particales to clog shift noids making it search for gears, and the particales and bad trans tune can make the clutch in the converter burn slip, let them check the trans again but send the converter back to get checked
Le Mans Master
Joined: Aug 2004
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From: Monroe Township New Jersey
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
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Anytime a transmission dies besides checking the converter you need to check all the coolant lines and the cooler too. Most come backs are the result of the tech not flushing the lines of debris or changing the trans cooler. ( replacing the radiator if the trans cooler is in the radiator)
Safety Car
Joined: Aug 2006
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From: Makena, Maui & NM
they cant clean the converter yank has to cut it open, when my trans went from a tsb then the tech screwed it up, i had them put the new trans in and sent the converter back to vig, i didnt even put it in because the trans was running hot, they found out the lines were clogged so they replaced all four, that means when the trans went they never cleaned the lines or did a flow test then the car ran that way for 1000 miles when they put the new lines on they never droped the pan to change the filter, gm is some crappy service
i know the trans needs exspert tuning or it doesnt get converter lockup and their is a tsb for mis machined case causing metal particales to clog shift noids making it search for gears, and the particales and bad trans tune can make the clutch in the converter burn slip, let them check the trans again but send the converter back to get checked
Could you translate into something simpler?....or did Tommy already do it for you? I know a converter does not need specfically to be be tuned, so what do you mean by a bad trans tune?....you mean by an unnamed bad tuner?
Last edited by siffert; Feb 26, 2009 at 10:33 AM.
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Safety Car
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From: Bethesda MD
+1 for sending the converter back and flushing the lines and tranny coolers. Like Tommy pointed out, you need to check the radiator cooler and your aftermarket. If your aftermarket cooler is a plate type cooler, I'd get a new one. They are harder to flush than a tube & fin design.
Safety Car
Joined: Jan 2008
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From: Middle of No where AK
I have been reading your posts here and I dont have a clue what you are saying about his or your prior problem. Could you translate into something simpler?....or did Tommy already do it for you? I know a converter does not need specfically to be be tuned, so what do you mean by a bad trans tune?....you mean by an unnamed bad tuner?
Could you translate into something simpler?....or did Tommy already do it for you? I know a converter does not need specfically to be be tuned, so what do you mean by a bad trans tune?....you mean by an unnamed bad tuner?your trans has to be adjusted for correct shift points when you add a converter. You also need to adjust the line pressure because it takes more fluid to make the converter to engage.
Melting Slicks
Joined: Jul 2007
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From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
With my car the only thing I had to do was lower my commanded shift points so that the actuals took place before hitting the rev-limited. Other than that my settings are 100% stock (including my line pressure) and the runs great.
Safety Car
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From: Bethesda MD
A converter rarely required tuning in a 4L60 F-body. Sometimes shift points would need a little touch up. People were running 3500 stalls well before tuning software was available. If it is truely different in the C6, I'm wondering if it is computer related.
Melting Slicks
Joined: Jul 2007
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From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
What I meant earlier by “commanded” vs. “actual” shift points is the difference between when the computer tells the transmission to shift (commanded) and when it really happens (actual). To use my buddy’s 08 as an example (he’s got a stock converter), his commanded 1-2 shift is set to 36 MPH and the car shifts at 45 MPH. With my car however, my 1-2 shift is set for 24 MPH but the car doesn’t actually shift until 37 MPH.
Essentially what happens is that the PCM figures a shift should occur in a certain amount of time after it tells the transmission to shift, but in the case of a high stall converter the RPMs shoot up much faster than expected so in order to account for this you need to lower your shift points accordingly. It’s sort of a case of the PCM giving the transmission a little more advance warning and although that may not be the best analogy I think it describes the situation reasonably well.
Team Owner
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Melting Slicks
Joined: Jun 2002
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From: Phoenix AZ
Yeah, that’s kinda what I thought too because I’ve talked to Dave about this and he said that converters are (for want of a better term) dumb in that they just do whatever the transmission tells them too.
What I meant earlier by “commanded” vs. “actual” shift points is the difference between when the computer tells the transmission to shift (commanded) and when it really happens (actual). To use my buddy’s 08 as an example (he’s got a stock converter), his commanded 1-2 shift is set to 36 MPH and the car shifts at 45 MPH. With my car however, my 1-2 shift is set for 24 MPH but the car doesn’t actually shift until 37 MPH.
Essentially what happens is that the PCM figures a shift should occur in a certain amount of time after it tells the transmission to shift, but in the case of a high stall converter the RPMs shoot up much faster than expected so in order to account for this you need to lower your shift points accordingly. It’s sort of a case of the PCM giving the transmission a little more advance warning and although that may not be the best analogy I think it describes the situation reasonably well.
What I meant earlier by “commanded” vs. “actual” shift points is the difference between when the computer tells the transmission to shift (commanded) and when it really happens (actual). To use my buddy’s 08 as an example (he’s got a stock converter), his commanded 1-2 shift is set to 36 MPH and the car shifts at 45 MPH. With my car however, my 1-2 shift is set for 24 MPH but the car doesn’t actually shift until 37 MPH.
Essentially what happens is that the PCM figures a shift should occur in a certain amount of time after it tells the transmission to shift, but in the case of a high stall converter the RPMs shoot up much faster than expected so in order to account for this you need to lower your shift points accordingly. It’s sort of a case of the PCM giving the transmission a little more advance warning and although that may not be the best analogy I think it describes the situation reasonably well.
I just got mine (L480E) back from the tuner after installing 3:15 gears to go along with my Vig 2400 converter and I am happy with it except for the downshifts. It seems to want to do a "double downshift" where it tries, hesitates, then downshifts. The tuner said he doesn't know what could cause this. Have you had this issue at all?
Thread Starter
Burning Brakes
Joined: Jun 2006
Posts: 1,164
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From: SOCAL CA
i think were sending the converter off tommorow..been out of town ..
Thread Starter
Burning Brakes
Joined: Jun 2006
Posts: 1,164
Likes: 1
From: SOCAL CA
Christopher,
I just got mine (L480E) back from the tuner after installing 3:15 gears to go along with my Vig 2400 converter and I am happy with it except for the downshifts. It seems to want to do a "double downshift" where it tries, hesitates, then downshifts. The tuner said he doesn't know what could cause this. Have you had this issue at all?
I just got mine (L480E) back from the tuner after installing 3:15 gears to go along with my Vig 2400 converter and I am happy with it except for the downshifts. It seems to want to do a "double downshift" where it tries, hesitates, then downshifts. The tuner said he doesn't know what could cause this. Have you had this issue at all?
Safety Car
Joined: Jan 2008
Posts: 4,711
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From: Middle of No where AK
Christopher,
I just got mine (L480E) back from the tuner after installing 3:15 gears to go along with my Vig 2400 converter and I am happy with it except for the downshifts. It seems to want to do a "double downshift" where it tries, hesitates, then downshifts. The tuner said he doesn't know what could cause this. Have you had this issue at all?
I just got mine (L480E) back from the tuner after installing 3:15 gears to go along with my Vig 2400 converter and I am happy with it except for the downshifts. It seems to want to do a "double downshift" where it tries, hesitates, then downshifts. The tuner said he doesn't know what could cause this. Have you had this issue at all?
This has to do with your line pressures and shift points. Mine did this before the tuner adjusted it in 3rd gear. I would be unlocked then lock almost like it was trying to find a gear that wasnt there. If you have hp tuners check you tranny settings it should be the 1st apply 2 apply etc settings.