Shifting problem. TM or shift solenoid???
Shifting problem. TM or shift solenoid??? ok heres the scenario. if I'm on the highway between 66 and 71 mph and I floor it it'll kick down into the top of second. The strange part is that it'll kick down then do a little stutter as if the computer is pulling timing for a moment then restoring it however if I leave my foot on the floor during this it'll very quickly shift into third where it'll accelerate extremely slowly as if I have serious timing retard for about 2 seconds then it'll kick back to full power.
I have very few mods in sig and I have since taken off the GMAF.
What could it be???
--Sky
<small>[ April 30, 2002, 07:32 AM: Message edited by: SOMSS670 ]</small>
I have very few mods in sig and I have since taken off the GMAF.
What could it be???
--Sky
<small>[ April 30, 2002, 07:32 AM: Message edited by: SOMSS670 ]</small>
TECH Addict
Joined: Nov 2001
Posts: 2,003
Likes: 0
From: Live Oak, FL - in the woods where the creatures lurk.
Re: Shifting problem. TM or shift solenoid??? It would be good if you could get a scanner on it while you're road testing. It sounds like TM, a combo of pulled timing and fuel. I get it on the 1-2 shift bigtime, as well as downshift to 1st. Unfortunately mine has gotten worse recently.
Re: Shifting problem. TM or shift solenoid??? By any chance do you have a TransGo shift kit installed? I have had the same problem but only after the shift kit install. The PCM goes into abuse mode because of the harsh 2-3 shift and will cut fuel and timing, holding the rpm's to 4500 until I pedal it (even with TM removed).
Mine is a known issue with TransGo and 01-02's. If you don't have a shift kit then you may want to look into custom PCM tuning.
Mine is a known issue with TransGo and 01-02's. If you don't have a shift kit then you may want to look into custom PCM tuning.
On The Tree
Joined: Nov 2001
Posts: 178
Likes: 0
From: So.Cal
Re: Shifting problem. TM or shift solenoid??? My car does the exact same thing as Reboot describes.If I keep it to the floor it will reaccelerate after 4-5 seconds.My tranny is stock and my only mods are FTRA and a lid.Abuse mode huh?
Re: Shifting problem. TM or shift solenoid??? I don't have a shift kit on mine. its just a regular old 4L60E and you can see in my sig my mods are minor I haven't even done the FRA
Staging Lane
Joined: Nov 2001
Posts: 57
Likes: 0
From: Warren,MI
Re: Shifting problem. TM or shift solenoid??? I have the same problem on my 2001 T/A. It started since I had a yank ST3200 stall installed. At first I thought it may be the 3rd gear clutches going bad. But, it may also be torque management. At wot 60 -70 car hesitates rpm's don't really climb then all of a sudden shifts into third and pulls real hard. Deffinitly not hitting the rev limiter cause rpms at about 4500-5200. Hooked up atap and seen the timming at -10 degrees, but can't be sure that it was at that exact time. I hope someone can figure this out. Maybe someone should ask ragtop99, he seems very knowledgable about our trans'.
TECH Apprentice
Joined: Jan 2002
Posts: 384
Likes: 0
From: Murphy, TX
Re: Shifting problem. TM or shift solenoid??? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by TAhawk69:
<strong>Hooked up atap and seen the timming at -10 degrees, but can't be sure that it was at that exact time.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That would be a dead giveaway if you can repeat and verify this.
<strong>Hooked up atap and seen the timming at -10 degrees, but can't be sure that it was at that exact time.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That would be a dead giveaway if you can repeat and verify this.
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TECH Regular
Joined: Nov 2001
Posts: 410
Likes: 0
From: Madison Heights, MI
Re: Shifting problem. TM or shift solenoid??? Sounds like the same thing my tranny is doing.I have custom tuning now but it still happened before a few times. I have ataped my car and no timing is droped at all. I'm currently working on figuring this out and we adjusted the max tq number from 650 to 950 and the actual shift is so much better now and when it doesn't hold the rpms I can spin the tires on the shift for the first time. I'm leaning on the abuse mode tables now and I'll post something soon about what we find out.
Re: Shifting problem. TM or shift solenoid??? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SOMSS670:
<strong>ok heres the scenario. if I'm on the highway between 66 and 71 mph and I floor it it'll kick down into the top of second. The strange part is that it'll kick down then do a little stutter as if the computer is pulling timing for a moment then restoring it however if I leave my foot on the floor during this it'll very quickly shift into third where it'll accelerate extremely slowly as if I have serious timing retard for about 2 seconds then it'll kick back to full power.
What could it be???
--Sky</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Holy ****! That is EXACTLY what my car does and has been doing ever since I got it! I have a lot more mods than you do but mine was doing that ever since it was stock. Last night on the way back from the track I was doing about 69 mph and I tried to race a C5. But when I hit WOT the car actually bounced off the rev limiter in 2nd (first time it did that) while at the same time doing it's stutter BS trying to make up its mind whether it wanted 2nd or 3rd gear...it's like it was stuck in between.
BTW, I have ls1edit and I have deleted TM, so it is not TM. I think it probably has something to do with TPS and what mph the car is set to shift from 2nd to 3rd. Just my guess.
Derrick
<strong>ok heres the scenario. if I'm on the highway between 66 and 71 mph and I floor it it'll kick down into the top of second. The strange part is that it'll kick down then do a little stutter as if the computer is pulling timing for a moment then restoring it however if I leave my foot on the floor during this it'll very quickly shift into third where it'll accelerate extremely slowly as if I have serious timing retard for about 2 seconds then it'll kick back to full power.
What could it be???
--Sky</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Holy ****! That is EXACTLY what my car does and has been doing ever since I got it! I have a lot more mods than you do but mine was doing that ever since it was stock. Last night on the way back from the track I was doing about 69 mph and I tried to race a C5. But when I hit WOT the car actually bounced off the rev limiter in 2nd (first time it did that) while at the same time doing it's stutter BS trying to make up its mind whether it wanted 2nd or 3rd gear...it's like it was stuck in between.
BTW, I have ls1edit and I have deleted TM, so it is not TM. I think it probably has something to do with TPS and what mph the car is set to shift from 2nd to 3rd. Just my guess.
Derrick
Re: Shifting problem. TM or shift solenoid??? Well I have my rev limiter set at 6600 and it still does it. Also, if I'm in 3rd or 4th, going about 68 mph, and I hit WOT to let the car shift to 2nd, my rpms should and are only somewhere around 5500, not 6600. So I have my doubts about it being a rev limiter problem.
It's as if the PCM is telling the car to shift into 2nd but as soon as it does, it tells it to shift into 3rd but then it sees that you are still WOT so it tells it to shift into 2nd again then immediately shifts back into 3rd!!! <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
Derrick
It's as if the PCM is telling the car to shift into 2nd but as soon as it does, it tells it to shift into 3rd but then it sees that you are still WOT so it tells it to shift into 2nd again then immediately shifts back into 3rd!!! <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
Derrick
TECH Addict
Joined: Nov 2001
Posts: 2,207
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From: College Station, Tx
Re: Shifting problem. TM or shift solenoid??? Log the event, and make sure to log tranny parameters (relevant) as well as MPH and timing.
If you get a timing drop like above likely there is a TM issue involved.
If not it is probably due to the particular shift settings - especially if you have re-scaled for new gears. Tuning shift points on an automatic is a PITA and is as much trial and error as anything else. Depending on what the log says you may want to increase either the downshift max mph (to prevent the downshift) or increase the shift mph (to give you more time before the shift occurse)
Chris
If you get a timing drop like above likely there is a TM issue involved.
If not it is probably due to the particular shift settings - especially if you have re-scaled for new gears. Tuning shift points on an automatic is a PITA and is as much trial and error as anything else. Depending on what the log says you may want to increase either the downshift max mph (to prevent the downshift) or increase the shift mph (to give you more time before the shift occurse)
Chris
