700R4 not working correctly
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Race Director
Joined: Dec 1999
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From: Forked River NJ
700R4 not working correctly
Now I know why I never own an automatic performance car. I have been working on this 82 Collecter edition and have the motor running OK but the trans is giving me fits. I adjusted the TV cable and that did not make any difference. The car sat for about 7 years. It has 49K miles on it and the owner says the trans was working fine before he took the interior out and some of the motor. I changed the trans fluid while I was resealing everything under the car. The car when you put it in gear moves but you have to rev it to get it to feel like it will move. When going down the road very slowly it really shudders hard and shifting is whenever it feels like it. I have not gotten over 15 mph for fear of doing major damage. It just feels likekthe trans wants to come out of the car. Almost like in a manual the clutch is slipping badly. Hating automatics more everyday. Any suggestions besides ripping it out and sending it off.
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I'm not sure of the technical name for it but there is an electronic module that controls the torque converter lock up. I believe it is externally mounted. It causes the car to run like it's in limp mode and worse but won't necessarily throw a CEL or code. My 82 CE had this fail at around 70K miles. Your issue sounds like a torque converter problem. Good luck. FWIW all five of my Vettes have been autos and I understand your frustration.
Thread Starter
Race Director
Joined: Dec 1999
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From: Forked River NJ
Never thought of that and I also have the dash out of the car so no VSS sensor is hooked up. It may be throwing codes like crazy I just have no way of knowing. I guess I should get it back in there before proceeding any further with it.
Racer
Joined: Jan 2011
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From: York Pa.
You say you adjusted the cable..can I ask how you did it..it can be done wrong..but it does sound like you have low line pressure..a gauge on the trans may give you an idea also..will the trans shift in manual mode..the pcm really only does lock up on these..does it go ok in reverse..is the trans fluid full..tough to diag a trans without a few more answers..
Burning Brakes
Joined: May 2008
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From: Middleburg Florida
I'm not sure of the technical name for it but there is an electronic module that controls the torque converter lock up. I believe it is externally mounted. It causes the car to run like it's in limp mode and worse but won't necessarily throw a CEL or code. My 82 CE had this fail at around 70K miles. Your issue sounds like a torque converter problem. Good luck. FWIW all five of my Vettes have been autos and I understand your frustration.
Thread Starter
Race Director
Joined: Dec 1999
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From: Forked River NJ
I adjusted the cable exactly like the GM manual says to do. I do not think it is torque converter related though. As you go to take off at a normal pace it goes then feels like it is slipping then shudders a lot. It never feels like it should in forward or reverse. Normally when shifting in forward or reverse you can feel it engage. It feels like it somewhat engages very softly and the rpms barely drop. I know it is tough to diagnos over the internet but I appreciate all the suggestions. Yes it is full of fluid. I'll be dropping the pan again I'm sure shortly jsu tto make sure all is OK in the pan area. I just need to get rid of some of the snow and get my car off to the paint shop.
Racer
Joined: Jan 2011
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From: York Pa.
Ok so the tv cable is set and the fluid is up to snuff..ok so if you don't have a gauge then let's move to the linkage..it really doesn't take much to get these out of adjustment..put the car in nuetral and take the key out..go under the car...make sure the car is lifted level..not jacked up on one wheel..release the linkage adjustment nut just a little..no manually put it in park and count the clicks to nuetral..2..wiggle the linkage to find the sweet spot in the middle and tighten up the linkage nut again ..ok if that fails you need a simple gauge to see what line pressure you have..I think you said it sat for a long time..who knows what may have shrunk or whatever in there..
Thread Starter
Race Director
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From: Forked River NJ
It is up on my lift right now but my car is underneath it. I'm hoping to get mine off to the paint shop this week as it is going to be warm and we are losing snow cover here. I should be able to get more into later this week. I'll make sure the linkage is set correctly and probably remove the pan if that is OK. I just have a bad feeling in the back of my head on the filter falling out a little. The old one that came off had double o rings on it. I found this strange. When I put the new one back in with 1 oring it went in very easily. Not the normal little snap that they usually go in with. It may be as simple as that.
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Racer
Joined: Jan 2011
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From: York Pa.
If I remember right the filter will only come out a tiny bit and hit the pan..the seal or o ring is perty important though ..you can raise the tv cable a bit by shortening it up a few clicks..do one at a time at the carb..if it doesn't change anything then it is something internal..
Thread Starter
Race Director
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From: Forked River NJ
When I adjusted it this morning it did shorten up about 3 clicks. Then when I went to WOT it clicked once so I shortened it about 2 clicks. This 82 still has the Cross fire injection. The filter I know can only drop a little but as yo usaid any leak may cause a problem.
Le Mans Master
Joined: Sep 2004
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From: Livonia MI
Sound's like it's tranny shop time before thing's get expensive. Had a chevy pick up with a 700R4 that was acting up and put it off for awhile. Ended up totally dying, needing a tow, and the case became internally scrapped. Thankfully was friend's with the shop owner, but you're not wanting to know the cost of that one.
Melting Slicks
Joined: Jul 2005
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From: Aurora Ontario
Odd problem. I guess it could be the transmission.
Just curious. When you put it in gear you say your really have to give it gas to get it moving.....are the RPM's rising when you give it gas in gear?
When driving it you also say it shudders and shifts when it wants. Do the RPM's go erratic as well?
My car did something similar when i first got it. I would give it gas and it would barely move. It eventually would start moving but slow and sluggish. The RPM's would hit about 2000 and hang....then the car would start to shudder....vibrate......then the transmission would kick in real hard....felt like the rearend was going to fall out.....then it would go a bit and start the samething all over. The cause of all this was low fuel pressure.....not enough fuel getting to the injectors. The ECM in these cars is primative....it can't tell its not getting fuel so it messes with everything it controls to compensate.
Jim
Just curious. When you put it in gear you say your really have to give it gas to get it moving.....are the RPM's rising when you give it gas in gear?
When driving it you also say it shudders and shifts when it wants. Do the RPM's go erratic as well?
My car did something similar when i first got it. I would give it gas and it would barely move. It eventually would start moving but slow and sluggish. The RPM's would hit about 2000 and hang....then the car would start to shudder....vibrate......then the transmission would kick in real hard....felt like the rearend was going to fall out.....then it would go a bit and start the samething all over. The cause of all this was low fuel pressure.....not enough fuel getting to the injectors. The ECM in these cars is primative....it can't tell its not getting fuel so it messes with everything it controls to compensate.
Jim
Melting Slicks
Joined: Jul 2005
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From: Aurora Ontario
Racer
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From: York Pa.
Wow school time ha..I know the trans but you opened another option of repair..the injection on these cars I don't really know..I stayed away from them..tuned port up thru LT1 I am good with..I didn't think the 700 started untill 85..ok..so this really can be something not related to the trans..schools open cross fire guys..bring it on.
Rich
Rich
Le Mans Master
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From: columbia city in
Racer
Joined: Jan 2011
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From: York Pa.
http://www.crossfire.homeip.net/index.php?act=idxfor future schooling
Melting Slicks
Joined: Jul 2005
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From: Aurora Ontario
I can honestly say I really don't want to know to much about the crossfire injection..but I am still wondering how a low fuel pressure could affect a trans..the only electronic thing in them is the lock up and that's a beyond simple circuit..unless it would rev high but no real power??..oh well see what the aldl says and go from there.
. The point is it may not be the transmission at all. They symptoms he describes are not entirely consistant with transmission failure.But somewhat consistant with a bad fuel pump and low fuel pressure, More info is needed.Jim
