BlkndGoldCutlass Posted November 18, 2013 Report Share Posted November 18, 2013 Well shortly after replacing the coil packs on my 1993 lumina z34 ,and got the engine to run perfectly, i started to experience transmission problems. It appears that i only have 1st and second gear no matter what speed im going it wont shift into third or OD. I hooked up a Tech2 to her to see if i could pull any codes. I couldnt find any, so i tried to shift it with the tech2 with no results. After that i unplugged the connector to the transmission and i defaulted into 3rd gear and ofcourse i still have second. I tried replacing the ecm/ecu (swapped with the one from my cutlass, kept prom) to see if the computer just wasn't telling it to do anything. that wasn't the case though. I just want your guy's opinion, im thinking either sprag, solenoid, or VSS (yet my speedo is working) any input would be greatly appreciated Quote Link to comment Share on other sites More sharing options...
Schurkey Posted November 19, 2013 Report Share Posted November 19, 2013 (edited) First Guess: If you have third gear with things unplugged, it's not a hard failure inside the trans. Sounds like a solenoid-control problem (outside the trans) to me. shortly after replacing the coil packs on my 1993 lumina z34 ,and got the engine to run perfectly, i started to experience transmission problems. I feel your pain. My '93 had all four gears and zero problems...until I did a valve job, head gaskets, and associated work on the 3.4. Engine runs fine. Within about twenty miles of test-driving, I had no gears at all--won't go forward, won't go backward. I've got Park and six neutrals on the floor shifter. Edited November 19, 2013 by Schurkey Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 19, 2013 Author Report Share Posted November 19, 2013 what would control the solenoid outside the transmission other than the ecm? Quote Link to comment Share on other sites More sharing options...
Schurkey Posted November 19, 2013 Report Share Posted November 19, 2013 (edited) what would control the solenoid outside the transmission other than the ecm? The ecm...based on inputs from a dozen sensors, and the wire harness that connects the whole mess together. I'd be looking at those dozen sensors, the wire harness, and the ecm--in about that order. Edited November 19, 2013 by Schurkey Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 19, 2013 Author Report Share Posted November 19, 2013 Ive tried replacing the ecm and all the sensors are new except the knock sensor lol Quote Link to comment Share on other sites More sharing options...
Schurkey Posted November 19, 2013 Report Share Posted November 19, 2013 Ive tried replacing the ecm and all the sensors are new except the knock sensor lol That kinda suggests the problem is in the wires, doesn't it? Do you KNOW that the replacement ecm was functioning properly? Do you KNOW that "all the sensors" work properly and are adjusted correctly if needed? When I hear "I replaced all the sensors..." I have a bad feeling that no scan tool was used to do appropriate diagnostics first. Please tell me that isn't the case here. Quote Link to comment Share on other sites More sharing options...
l67ss Posted November 19, 2013 Report Share Posted November 19, 2013 You didnt use pipe tape on the threads of the sensors, did ya? Ive tried replacing the ecm and all the sensors are new except the knock sensor lol Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 19, 2013 Author Report Share Posted November 19, 2013 All the engine related sensors were replaced when we rebuilt the engine b/c we were already that far so why not and no i didn't use thread tape, give me some credit lol. more info- I'm about 2hrs away from the car right now in college and my dad just today replaced the battery in it to move it b/c it crapped out just out of no where. he has not driven it too far after battery replacement tho. could the bad battery have had an affect? i don't want to sound stupid with that question but it just came across my mind. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 20, 2013 Report Share Posted November 20, 2013 checked on something i thought about: on the 91-93 3.4 4T60E, there is a 1st and 4th gear switch signal. these are basically "request" circuits, in that the PCM uses them to detect where the shifter is at to know when to prevent/allow gear changes. i was thinking there was one for 3rd gear as well, but i guess not. that being the case, the 1st gear request can be bypassed and shifted into 2nd gear if RPM and MPH are high enough, but no higher speeds will be allowed. so, should the PCM detect that 1st gear is being requested, that will give you 1st and 2nd, but no other gears. 1st gear request should be the only red wire on the trans connector, depending on shifter position, you should see the circuit go from open circuit to closed to ground. should be open in all shifter positions except for when in 1st. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 20, 2013 Report Share Posted November 20, 2013 oh, GM's possible causes for only having 1st-2nd: shift solenoid failure 1st gear request signal circuit grounded shift solenoid wire shorted to ground Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 20, 2013 Author Report Share Posted November 20, 2013 So what your saying is that I may be having issues with my first gear command wiring? So check that red wire for issues from the plug to the pcm? If I understand you correctly. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 20, 2013 Report Share Posted November 20, 2013 it's either that or a problem internal to the transmission. i would monitor voltage on the circuit with it all hooked together and ignition on to see if it is switching as it should. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted November 20, 2013 Report Share Posted November 20, 2013 Start with the switch/sensor on the shift lever; or that the shift lever controls at the trans shift linkage. Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 22, 2013 Author Report Share Posted November 22, 2013 well after attempting all the things you guys thought of i gave up and had my dad take it to a local transmission shop. Found out that my clutch packs are pretty much gone and that's what clogged up my solenoids. plus i have some metal chunks in my pan. i had 2 choices 1. replace it with a used transmission with no warranty- $950 or a full rebuild with 1 year warranty $1350. needless to say i chose the rebuild:confused: thanks for all your help fellas:biggrin: Quote Link to comment Share on other sites More sharing options...
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