Automatic Transmission 2-Speed thru 10-Speed GM Autos | Converters | Shift Kits
Sponsored by:
Sponsored by:

1-2 shift problem after stall

Thread Tools
 
Search this Thread
 
Old 08-11-2007, 02:45 PM
  #1  
On The Tree
Thread Starter
iTrader: (3)
 
coocooknu's Avatar
 
Join Date: Jul 2006
Location: Mt. Prospect, IL
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Unhappy 1-2 shift problem after stall

Heres the deal. I recently installed a vig 3200 stall and 2 trans coolers into my 98 formula with just over 80k on the clock. drove the stall about 100 miles with nothing but traction problems i then went for a longer drive today 60-70 mi. and it was mildly hot outside. at about 15mi from home i noticed when shifting from 1-2 the trans felt like it would shudder before sticking 2nd gear. it has never done this before this long trip and i dont have a clue as to what would cause this. i figured it maybe overheated (dont have a temp gauge yet), but my friend mentioned that it might be a solenoid. Any and all advice is appreciated, please help me fix my trans!
Old 08-11-2007, 03:08 PM
  #2  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

I wonder if you have a 1-2 accumulator piston that is cracked or a band that is beginning to fail. A cracked piston will cause a partial band apply in first gear and almost feel like second gear starts. How is the condition of the oil?

Last edited by FLT; 08-11-2007 at 06:41 PM.
Old 08-11-2007, 03:46 PM
  #3  
On The Tree
Thread Starter
iTrader: (3)
 
coocooknu's Avatar
 
Join Date: Jul 2006
Location: Mt. Prospect, IL
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default

I checked the oil right after the drive and it was right between the two holes for "hot" so i dont think the problem is there
Old 08-11-2007, 06:47 PM
  #4  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

When your trans does this how hard are you on the throttle? You said that it seemed to shutter before sticking 2nd gear. I'm assuming that this occurs during the shift. That is why I recommended that you have a band that is failing or a cracked 1-2 accumulator piston or combination of both. If it continues to do this feel free to give me a call and maybe you can bring it by for me to take a look at it. We are located in Wood Dale if that helps. Is this the original transmission in the vehicle with 80K on it?
Old 08-11-2007, 07:06 PM
  #5  
On The Tree
Thread Starter
iTrader: (3)
 
coocooknu's Avatar
 
Join Date: Jul 2006
Location: Mt. Prospect, IL
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default

Well here is what I did, I let the car cool for about 4 hours. My friend came over and used his OBD II scanner and found out it was throwing a code, dont remember which off the top of my head, but it said something about 1-2 shift. He cleared the code and we went for a drive and the car had to problems whatsoever. My best guess is that it overheated.
Old 08-11-2007, 07:23 PM
  #6  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

Was the code a PO751?
Old 08-11-2007, 09:52 PM
  #7  
Teching In
 
z28landon's Avatar
 
Join Date: Apr 2006
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default

my car has been doing this lately also.

It's only when I am on the throttle up to 3000rpms. then when it tries to shift it feels like my car is in neutral. then after a few seconds it will shift.

WTF???

But on the other hand if I go WOT my car will shift just fine!


also if I let it downshift to 1st on WOT it shifts way hard!

what would be my problem?

I seriously need to get my tranny cooler installed!
Old 08-11-2007, 10:15 PM
  #8  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

Which gear are we talking about when this neutral problem occurs at 3000rpm? 1-2, 2-3, ?????
Old 08-11-2007, 10:56 PM
  #9  
12 Second Club
iTrader: (4)
 
formulamd's Avatar
 
Join Date: Apr 2006
Location: Palatine
Posts: 94
Likes: 0
Received 0 Likes on 0 Posts
Default

The code was PO1870 i believe.
Old 08-11-2007, 11:15 PM
  #10  
LS1Tech Sponsor
iTrader: (25)
 
performabuilt's Avatar
 
Join Date: Aug 2006
Location: BLOOMSBURG PA
Posts: 10,858
Received 78 Likes on 56 Posts

Default

PO1870 is generally a converter clutch code it means componet slipping but in most cases means the converter clutch is slipping excessivley , This can be because the converter clutch is bad or the converter clutch regulator valve is worn and or the PWM solenoid is bad or the small filter in it clogged, With small diameter converters it can just mean the clutch due to being to small is allowing to much slip , This function PWM should be eliminated with any small diameter converter installation, We mechanically eliminate it on all our transmissions
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542



Last edited by performabuilt; 08-11-2007 at 11:21 PM.
Old 08-12-2007, 06:52 AM
  #11  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

Originally Posted by performabuilt
This function PWM should be eliminated with any small diameter converter installation, We mechanically eliminate it on all our transmissions
I disagree with this statement. Reduce it yes eliminate it no. We use the trans-go kit and the regulator valve in this kit does just this, reduce PWM. Most guy's will use a longer spring to eliminate this function. This is a poor mans way of trying to fix a problem so to speak. This method of eliminating the PWM does not work with all computers. Also causes some drive-ability issues. Most guy's do this PWM mod because it is cheaper then buying a quality shift kit or a special regulator valve that requires boring a valve body. Both of which cost time and money. I personally would rather spend a little extra and give you a better product. Then again I'm a high maintenace builder and money to me is really not an issue when it comes to building. Vince

Last edited by FLT; 08-12-2007 at 07:26 AM. Reason: I won't say!
Old 08-12-2007, 10:57 AM
  #12  
On The Tree
Thread Starter
iTrader: (3)
 
coocooknu's Avatar
 
Join Date: Jul 2006
Location: Mt. Prospect, IL
Posts: 101
Likes: 0
Received 0 Likes on 0 Posts
Default

Will it cause any long term damage if I don't deal with this problem right now? As of right now the car runs fine, it only happened when i went for that long drive on that hot day, most of my drives are fairly short around town.
Old 08-12-2007, 11:17 AM
  #13  
LS1Tech Sponsor
iTrader: (25)
 
performabuilt's Avatar
 
Join Date: Aug 2006
Location: BLOOMSBURG PA
Posts: 10,858
Received 78 Likes on 56 Posts

Default

Then we agree to disagree. My issue with the PWM has to do with duty cycles and converter clutch area. For instance lets say the 12 inch converter has X area and ou reduce the converter size to 9 inches now the clutch area is 1/3 less, Then you set up the clutch for a 90 percent duty cycle on each in the tuning. The 9 inch due to friction area is going to have 30 percent more allowed slipage than its 12 inch counterpart. Will become much hotter and wear the converter clutch prematurley. As for ill effects with the PCM I have only noted that the PCM does enable lockup a little early on some of the later units but this is easily addressed again in tuning by raisng the lockup points , Just my observation each of us has a different way of getting from A TO B and in each case it seems to work since neither of us seems to have encountered converter failure issues with our respective methods. I have noted that retaining PWM also with multi disk converters though they have the nessesary friction area tends to result in converter chatter during the partial lockup.I am not sure why this is but have experinced it several times.
Originally Posted by Vince @ FLT
I disagree with this statement. Reduce it yes eliminate it no. We use the trans-go kit and the regulator valve in this kit does just this, reduce PWM. Most guy's will use a longer spring to eliminate this function. This is a poor mans way of trying to fix a problem so to speak. This method of eliminating the PWM does not work with all computers. Also causes some drive-ability issues. Most guy's do this PWM mod because it is cheaper then buying a quality shift kit or a special regulator valve that requires boring a valve body. Both of which cost time and money. I personally would rather spend a little extra and give you a better product. Then again I'm a high maintenace builder and money to me is really not an issue when it comes to building. Vince
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Old 08-12-2007, 01:06 PM
  #14  
FLT
FormerVendor
iTrader: (1)
 
FLT's Avatar
 
Join Date: Sep 2005
Location: Wood Dale, Illinois
Posts: 6,620
Likes: 0
Received 3 Likes on 3 Posts

Default

Originally Posted by coocooknu
Will it cause any long term damage if I don't deal with this problem right now? As of right now the car runs fine, it only happened when i went for that long drive on that hot day, most of my drives are fairly short around town.
Sorry to go

I personally would consider installing the trans-go kit, update your separator plate, and also the accumulator pistons. I believe that this will help your situation providing that damage has not already occurred to your transmission. Like I said earlier feel free to give me a call if the problem persists. I do stock and sell the parts that you would require. With a stall you really need to get a cooler on there ASAP and I can help you out with that as well. Thank you for your time. Vince
Old 08-12-2007, 05:55 PM
  #15  
Teching In
 
z28landon's Avatar
 
Join Date: Apr 2006
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Vince @ FLT
Which gear are we talking about when this neutral problem occurs at 3000rpm? 1-2, 2-3, ?????

it's only 1-2 but after driving it today. it almost feels like the engine isn't getting fuel or something I have never had this problem in a car ever before.. it's like when I come to a dead stop then accelerate about 50% throttle it's like all of a sudden the car just holds back or something, it doesn't feel so much like a misfire. it doesn't sputter. it just like falls asleep and then a few seconds later it catches back up and it's fine. I took a friend for a ride today, he thought maybe the fuel filter was clogged or something...it is at least 4 years old.

It's weird because I don't think it's the tranny... If I let the car down shift at WOT. it shifts nice and firm. and basically has no problem anywhere (1-2-3 shifts) I really think it's more of a hesitation problem the more I drive it. like I said the thing that bugs me is it's not consistent.it's once in a while
Old 08-12-2007, 05:58 PM
  #16  
LS1Tech Sponsor
iTrader: (25)
 
performabuilt's Avatar
 
Join Date: Aug 2006
Location: BLOOMSBURG PA
Posts: 10,858
Received 78 Likes on 56 Posts

Default

Well from that description it does sound more like a engine running issue than a trans issue. I would get it on a scanner or tuner and look and see what alls happening intermitamt issues can be a pain I know
__________________
Built..PerformaBuilt..Tough

Call 888-744-6542


Old 08-12-2007, 07:05 PM
  #17  
TECH Fanatic
iTrader: (1)
 
BubaGumpShrimp's Avatar
 
Join Date: Jul 2003
Location: edison, nj
Posts: 1,095
Likes: 0
Received 0 Likes on 0 Posts

Default

you need a tune, your having torque management issues. When this happens the computer cuts fuel and timing untill the torque numbers fall with in range and then the shift will happen...




All times are GMT -5. The time now is 03:39 AM.