4L60E Help
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Teching In
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4L60E Help Ok, so the story goes. I have an 07 Silverado new body style. One night driving under hard acceleration 1st to 2nd shift resulted in a bang, tire chirp and in no gear after that. I could move the shifter from D to 3rd and it would find a gear, it wouldnt do it automatically, and it would squeal and shudder.
So that transmission was replaced with a rebuilt one. The rebuilt one never really acted right, seemed like it would search for a 3rd to 4th shift. But the main issue at hand is that the torque converter is constantly locking and unlocking or slipping from 38-55 mph. Seems worse at kind of a cruising throttle position, apply more throttle it is seems to stay locked, although not completely. So before I could get a replacement transmission we decided to rule out some things on the vehicle, brake switch and throttle position sensor seem ok based on the scan tool. The guy reading the tool said that in the 38-55 rpm range the torque converter slippage was all over the place from 0-250 rpms, once above 55 it went to 0.
So we decide to send in the transmission under warranty. Now we get another rebuilt transmission, swap it and have the same problem. Although the lock and unlock isnt as pronounced or as bad and the shifting seems much better it still locks and unlocks in essentially the same fashion as the previous rebuilt transmission.
The stock transmission never had these issues, ever since the stock transmission broke I have had nothing but problems with the torque converter lockup between 38-55 mph. Should also mention no codes stored. Any ideas?
So that transmission was replaced with a rebuilt one. The rebuilt one never really acted right, seemed like it would search for a 3rd to 4th shift. But the main issue at hand is that the torque converter is constantly locking and unlocking or slipping from 38-55 mph. Seems worse at kind of a cruising throttle position, apply more throttle it is seems to stay locked, although not completely. So before I could get a replacement transmission we decided to rule out some things on the vehicle, brake switch and throttle position sensor seem ok based on the scan tool. The guy reading the tool said that in the 38-55 rpm range the torque converter slippage was all over the place from 0-250 rpms, once above 55 it went to 0.
So we decide to send in the transmission under warranty. Now we get another rebuilt transmission, swap it and have the same problem. Although the lock and unlock isnt as pronounced or as bad and the shifting seems much better it still locks and unlocks in essentially the same fashion as the previous rebuilt transmission.
The stock transmission never had these issues, ever since the stock transmission broke I have had nothing but problems with the torque converter lockup between 38-55 mph. Should also mention no codes stored. Any ideas?
Last edited by sprint_9; Jan 2, 2017 at 08:21 PM.
Can it be assumed that you also replaced the torque converter?
Ok, so the story goes. I have an 07 Silverado new body style. One night driving under hard acceleration 1st to 2nd shift resulted in a bang, tire chirp and in no gear after that. I could move the shifter from D to 3rd and it would find a gear, it wouldnt do it automatically, and it would squeal and shudder.
So that transmission was replaced with a rebuilt one. The rebuilt one never really acted right, seemed like it would search for a 3rd to 4th shift. But the main issue at hand is that the torque converter is constantly locking and unlocking or slipping from 38-55 mph. Seems worse at kind of a cruising throttle position, apply more throttle it is seems to stay locked, although not completely. So before I could get a replacement transmission we decided to rule out some things on the vehicle, brake switch and throttle position sensor seem ok based on the scan tool. The guy reading the tool said that in the 38-55 rpm range the torque converter slippage was all over the place from 0-250 rpms, once above 55 it went to 0.
So we decide to send in the transmission under warranty. Now we get another rebuilt transmission, swap it and have the same problem. Although the lock and unlock isnt as pronounced or as bad and the shifting seems much better it still locks and unlocks in essentially the same fashion as the previous rebuilt transmission.
The stock transmission never had these issues, ever since the stock transmission broke I have had nothing but problems with the torque converter lockup between 38-55 mph. Should also mention no codes stored. Any ideas?
So that transmission was replaced with a rebuilt one. The rebuilt one never really acted right, seemed like it would search for a 3rd to 4th shift. But the main issue at hand is that the torque converter is constantly locking and unlocking or slipping from 38-55 mph. Seems worse at kind of a cruising throttle position, apply more throttle it is seems to stay locked, although not completely. So before I could get a replacement transmission we decided to rule out some things on the vehicle, brake switch and throttle position sensor seem ok based on the scan tool. The guy reading the tool said that in the 38-55 rpm range the torque converter slippage was all over the place from 0-250 rpms, once above 55 it went to 0.
So we decide to send in the transmission under warranty. Now we get another rebuilt transmission, swap it and have the same problem. Although the lock and unlock isnt as pronounced or as bad and the shifting seems much better it still locks and unlocks in essentially the same fashion as the previous rebuilt transmission.
The stock transmission never had these issues, ever since the stock transmission broke I have had nothing but problems with the torque converter lockup between 38-55 mph. Should also mention no codes stored. Any ideas?
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Yes, use a scanner to read the TPS value and make sure it goes from 0% to close to 100%.
For example, if your TPS were to read 20% with the throttle closed, and you use 20% throttle to cruise, the total would be 40% and the TCC is designed (tuned) to unlock around 40%.
For example, if your TPS were to read 20% with the throttle closed, and you use 20% throttle to cruise, the total would be 40% and the TCC is designed (tuned) to unlock around 40%.
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Teching In
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Thanks for the replies. Ill look into the tps a little closer.
Couple questions, does HP tuners and its VCM scanner work for these needs? I have a need for this down the road I might just get it now if it will help, which I assume it will.
Also, I just so happen to have a brand new throttle body sitting on the shelf from an LS swap that Im working on, and it is the exact same engine. Is this something that I can just swap to try or does it need to be calibrated?
Couple questions, does HP tuners and its VCM scanner work for these needs? I have a need for this down the road I might just get it now if it will help, which I assume it will.
Also, I just so happen to have a brand new throttle body sitting on the shelf from an LS swap that Im working on, and it is the exact same engine. Is this something that I can just swap to try or does it need to be calibrated?
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Teching In
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Hp Tuners should be here Friday.
I decided to try swapping the throttle body today, it was the exact same part number so I thought I would try it, worked great except that it didnt affect the problem in any way. Im pretty confident I can rule that out.
After thinking about this more Im starting to lean toward it being a tuning issue. To me it makes sense in that the truck was programmed for and had learned the stock transmission. All the sudden it is gone and now the new ones have been a little bit different as far as what they need for pressures, tcc duty cycle, etc. The latest transmission I have installed now seems to be closer to what the truck is used to as it behaves more normal, but it still needs some work. Once HP Tuners gets here I think I will play slightly with the tcc duty cycle and the adaptive transmission settings
Through my searches I finally found someone with a very similar problem to me. https://ls1tech.com/forums/automatic...uty-cycle.html
I decided to try swapping the throttle body today, it was the exact same part number so I thought I would try it, worked great except that it didnt affect the problem in any way. Im pretty confident I can rule that out.
After thinking about this more Im starting to lean toward it being a tuning issue. To me it makes sense in that the truck was programmed for and had learned the stock transmission. All the sudden it is gone and now the new ones have been a little bit different as far as what they need for pressures, tcc duty cycle, etc. The latest transmission I have installed now seems to be closer to what the truck is used to as it behaves more normal, but it still needs some work. Once HP Tuners gets here I think I will play slightly with the tcc duty cycle and the adaptive transmission settings
Through my searches I finally found someone with a very similar problem to me. https://ls1tech.com/forums/automatic...uty-cycle.html
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Teching In
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Just wanted to update in case someone else has a similar problem.
Played around with HP Tuners tonight, working on the TCC Duty Cycle percentage. Stock started it out as kind of wave depending on where temp and pressure was. I tried small steps, making a change of like 5 points across the entire table to bring the minimum from 9 to 14. Didnt see much change after a test drive, so I tried again to 20. Small change but not enough, kept creeping up until I hit 33. Its pretty close there, it no longer surges or slips excessively. Might try bumping it a little more but Im pretty happy with it, back to being very close to normal.
Played around with HP Tuners tonight, working on the TCC Duty Cycle percentage. Stock started it out as kind of wave depending on where temp and pressure was. I tried small steps, making a change of like 5 points across the entire table to bring the minimum from 9 to 14. Didnt see much change after a test drive, so I tried again to 20. Small change but not enough, kept creeping up until I hit 33. Its pretty close there, it no longer surges or slips excessively. Might try bumping it a little more but Im pretty happy with it, back to being very close to normal.