Weird, transmission won't shift unless commanded by VCM controls
10-21-2010, 06:32 PM
#1
Weird, transmission won't shift unless commanded by VCM controls Ok.. Here is the deal.. It has worked for years with no issues:
New 418ci motor with 4L80E driven by 01 F-body computer and a HP tuners trans segment swap.. Took a buddy for a ride in it on the way to a funeral. Halfway there, in 4rth gear, part throttle 53mph I have nothing. I try down shifting nothing. Come to a stop and it doesn't even want to relly pull away in first.
Open up the VCM controls in HPtuners because I use the laptop for guages. Through VCM controls it finds every gear when I command as well as verter lock up. This is the only way I could have gotten it home because it was going no where on it's own. (THANKS HPTUNERS!!!)
Looking at my data log, I can see the computer command the verter unlock and gear change from 4 down to 2 when I first had the problem..
Any thoughts or ideas would be greatly appreciated!!
New 418ci motor with 4L80E driven by 01 F-body computer and a HP tuners trans segment swap.. Took a buddy for a ride in it on the way to a funeral. Halfway there, in 4rth gear, part throttle 53mph I have nothing. I try down shifting nothing. Come to a stop and it doesn't even want to relly pull away in first.
Open up the VCM controls in HPtuners because I use the laptop for guages. Through VCM controls it finds every gear when I command as well as verter lock up. This is the only way I could have gotten it home because it was going no where on it's own. (THANKS HPTUNERS!!!)
Looking at my data log, I can see the computer command the verter unlock and gear change from 4 down to 2 when I first had the problem..
Any thoughts or ideas would be greatly appreciated!!
10-21-2010, 08:57 PM
#3
Vince,
I was in OD at the time of the issue. But, if I comand 1st, 2nd 3rd or even OD through HPtuners VCM controls, it takes to each gear with no issues. It also has no problem locking the verter in 2nd 3rd and OD with the VCM controls.
The problem is only when I let it do it on it's own through the PCM. IE not using HPtuners VCM controls.
If a clutch pack welded together, would I still have each gear individually through the VCM controls? Seems like what ever clutch pack is welded would not work properly.
Say it was 3rd that welded together, would I still have 1 2 and 4 through standard PCM controls? Or if it was say 2nd, would I still have 1 3 and 4 through normal PCM controls? Again, seems like one of the gears would have an issue.
If it was the OD roller, would that still allow me to have each gear through the VCM controls, including OD?
I know little about how tranny's work, so any inout is a huge help. I'm only asking these questions as I am trying to understand why it would work fine through the VCM controls and not the "regular" way.. It's not to question your knowlege..
I was in OD at the time of the issue. But, if I comand 1st, 2nd 3rd or even OD through HPtuners VCM controls, it takes to each gear with no issues. It also has no problem locking the verter in 2nd 3rd and OD with the VCM controls.
The problem is only when I let it do it on it's own through the PCM. IE not using HPtuners VCM controls.
If a clutch pack welded together, would I still have each gear individually through the VCM controls? Seems like what ever clutch pack is welded would not work properly.
Say it was 3rd that welded together, would I still have 1 2 and 4 through standard PCM controls? Or if it was say 2nd, would I still have 1 3 and 4 through normal PCM controls? Again, seems like one of the gears would have an issue.
If it was the OD roller, would that still allow me to have each gear through the VCM controls, including OD?
I know little about how tranny's work, so any inout is a huge help. I'm only asking these questions as I am trying to understand why it would work fine through the VCM controls and not the "regular" way.. It's not to question your knowlege..
10-22-2010, 05:42 AM
#6
OK sorry I was a little tired when I posted last night. Let me make sure I have this right. Your car basically went into neutral while going down the road in OD. You tried to manually put the shifter into D3 and still no movement. Then you hook up HP tuners to the vehicle control the trans from a stop and all is working as it should.
My question is what happens to the transmission line pressure when this problem happens and also what happens when hp tuners is connected after the problem pressure wise? If for some reason your vehicle goes into a limp mode it should still move when it comes to a stop but it would feel like a slipping trans for obvious reasons. 2nd gear starts. However with you using HP tuners to get things working I question if the transmission line pressure is raised while in this mode. This might mask an internal trans issue because we have added pressure to a problem.
I guess at this point it is possible that you have a control issue via the computer or a trans issue. If it were me I would probably drop the pan to do a visual inspection. If its full of debris and what not pull the trans to inspect future. If all looks well you might want to check all your wiring especially the grounds. Being as how you just installed a new engine anything is possible. Good luck getting this figured out and please post up what you find. Vince
My question is what happens to the transmission line pressure when this problem happens and also what happens when hp tuners is connected after the problem pressure wise? If for some reason your vehicle goes into a limp mode it should still move when it comes to a stop but it would feel like a slipping trans for obvious reasons. 2nd gear starts. However with you using HP tuners to get things working I question if the transmission line pressure is raised while in this mode. This might mask an internal trans issue because we have added pressure to a problem.
I guess at this point it is possible that you have a control issue via the computer or a trans issue. If it were me I would probably drop the pan to do a visual inspection. If its full of debris and what not pull the trans to inspect future. If all looks well you might want to check all your wiring especially the grounds. Being as how you just installed a new engine anything is possible. Good luck getting this figured out and please post up what you find. Vince
10-22-2010, 12:12 PM
#7
Vince,
Thanks for the feedback.
Yes I was in OD and it then felt like I was in N..
I run HPtuners 24/7 when I drive the truck because I don't have guages (other than oil pressure). This means I was data loging when it happenened.
It shows OD with 100% lock on ther verter, then all of a sudden the dataloger shows D2 with 0% verter. Blipped the throtlle 4 or so times when it felt like I hit nutral. Slowed down to a stop when I realized nothing was there.
Looking at the log, there is a 2 to 1 command through the data loger at 38mph. RPM did not jump up which would normally happens if I move the shifter (But I can't remember for sure if I moved it or not).
At my stop, I know I put it in D1. Pulled away at 15% throttle, got up to 34mph which is 4,500rpm. At some point before 4,500 I know I tried shifting to D2 but the data logger does not show it. Grabbed the mouse and forced it in to D3 which it was happy to find. 5 seconds later forced OD which again it found and 7 seconds later forced lock up, which it found.
Looking at the log right now, I shortly went down a pretty steep slow hill. At the bottom there is a stop. Just before the hill, I get off the gas at 46mph, and I unforce the VCM controls allowing the trans to do what it wants:
At 42mph it unlocks the verter.
At 41 (2 seconds later) PCM commands D2
At 37mph (6 seconds later) PCM commands D1
Stays in D1 to the stop sign
Pull away and it's still in D1 with the shifter in the OD position
Get up to 3,450 (26mph) with no gear change.
Hold 7% throttle before forcing D2 (6 seconds later)
Hold 7% throttle before forcing D3 (5 seconds later)
Go over some railroad tracks (30 seconds later) Force OD
Find all gears ect, but I decided to turn around and go home to get another car. I had a funeral to be at and didn't want the truck leaving me stranded.
Finds all gears/verter lock up on the way home when forced.
At one point just before turning around, my nostrils got a wiff of a burning smell. It was very faint and very quick (maybe my imagination).. This is what made me decide to turn around. Data logger shows I only had 163* trans temp once getting home in the driveway and it was never hotter than that through the full ride.
That's all I have right now.. Any more questions I'll be happy to answer. I'll try to help you help me
Thanks again Vince, I really appreciate the info..
Thanks for the feedback.
Yes I was in OD and it then felt like I was in N..
I run HPtuners 24/7 when I drive the truck because I don't have guages (other than oil pressure). This means I was data loging when it happenened.
It shows OD with 100% lock on ther verter, then all of a sudden the dataloger shows D2 with 0% verter. Blipped the throtlle 4 or so times when it felt like I hit nutral. Slowed down to a stop when I realized nothing was there.
Looking at the log, there is a 2 to 1 command through the data loger at 38mph. RPM did not jump up which would normally happens if I move the shifter (But I can't remember for sure if I moved it or not).
At my stop, I know I put it in D1. Pulled away at 15% throttle, got up to 34mph which is 4,500rpm. At some point before 4,500 I know I tried shifting to D2 but the data logger does not show it. Grabbed the mouse and forced it in to D3 which it was happy to find. 5 seconds later forced OD which again it found and 7 seconds later forced lock up, which it found.
Looking at the log right now, I shortly went down a pretty steep slow hill. At the bottom there is a stop. Just before the hill, I get off the gas at 46mph, and I unforce the VCM controls allowing the trans to do what it wants:
At 42mph it unlocks the verter.
At 41 (2 seconds later) PCM commands D2
At 37mph (6 seconds later) PCM commands D1
Stays in D1 to the stop sign
Pull away and it's still in D1 with the shifter in the OD position
Get up to 3,450 (26mph) with no gear change.
Hold 7% throttle before forcing D2 (6 seconds later)
Hold 7% throttle before forcing D3 (5 seconds later)
Go over some railroad tracks (30 seconds later) Force OD
Find all gears ect, but I decided to turn around and go home to get another car. I had a funeral to be at and didn't want the truck leaving me stranded.
Finds all gears/verter lock up on the way home when forced.
At one point just before turning around, my nostrils got a wiff of a burning smell. It was very faint and very quick (maybe my imagination).. This is what made me decide to turn around. Data logger shows I only had 163* trans temp once getting home in the driveway and it was never hotter than that through the full ride.
That's all I have right now.. Any more questions I'll be happy to answer. I'll try to help you help me
Thanks again Vince, I really appreciate the info..
