Trans shift 1-2 issues

htrdlincoln98

htrdlincoln98

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Lately the 1-2 shift has been short shifting to second, before it goes to second it shifts back to first until the right time for second. Its basically short shifting then going back to run out first. Its hell on my dial ins. It doesn't do this that often just when it feels like I guess. Sometimes it happens first or second run time trials, or then it will happen later in the night. However its not every time to the track. I've check fliud levels and looks good, fluid also looks and smells good. Trans runs and shift good other than this. Also the wiring harness is cracked but its been like that for a long time. Any ideas on this.
 
Did you make any changes in your tune recently? Especially to the shift schedules. My guess is it's either sometihng in the tune or chafed wiring.
 
97 or 98 if a 97 check the wiring inside the tranny, I also would lean toward shift schedules being off, a flaky speed sensor could also cause 1st to second shift issues.
PS if you can data log take a look at the shift points and see if the PCM is causing the problem if not I would lean toward wiring or shift solenoids.
 
start logging your trans temps..before and after the runs.

my first gen would do some "stupid stuff" sometimes on my third "round robin run".
I used to make 3 passes
first 1 hour cool down
then back to the lanes for a hot pass
then back to the lanes for a round robin hot pass.
After thousands of passes I trimmed it down to
1 cold
1 round robin

at our track when you get into the semi's that's usually a hot pass from the 1/4's, then they call the winners straight back to the lanes.. thus the three pass TNT strategy {sorry for the off topic novel)
 
I haven't made any shift changes in the tune. With the sniper I really cannt change any thing other that WOT. The plastic wire inside the case is cracked and has been that way for some time. That could be it but I'm leaning to a pcm issue. I also cannt log any of the temps. Not even sure if I can log any of the trans commands. I would like to locate which wire going into th ecase works the 1-2 solinoid and check the command that way. If it's not getting the command then it must be in the trans. As for the speed sensor that may show up in a log as the mph jumping around? Its not all the time some weeks it never shows up. The round robin deal doesn't always cause the issue.
 
Its very possible its a wire the PCM works via pulling ground, so if a wire is intermitantly shorting it could be pulling the first gear on.
 
Would a weak solinoid only act up at wot situation. What I mean is could the rpm or pressure cause this. When it happens it is at the same rpm range always. I want to bring to the trans shop but it doesn't happen very often. Now its a hard call what to do. What do you think. Add a cooler and change fluid while the pans down install no harness.
 
Not sure what that would have done. It acts like an electrical issue. Still catches second and shifts good other wise.
 
I installed a TransGo a couple of years ago in my 96, and when hot it seemed to 'slip' off the line (coming out of toll gates)-so I installed a trans cooler, and it shifts quickly with no issues now . If I drive it easy, it is not real harsh, if I get on it, it'll bark 2ed and chirp 3rd, no problem consistently-you need a transcooler, especially w/your mods.
 
I guess its time for the cooler. It can hurt anything but the wallet. The car shifts great except this once in awhile issue. Only at WOT. No complants with the shift kit, mmt your issue may not be the shift kit. If its too much I'll put my fresh trans in. Its Jmoded from blendderhead.
 
Its the transgo kit, pull and replace the valve body the modification to the valve body can cause terrible problems with use, Do the J mod or go with Baumman kit.
Its my understanding that the relief hole that is drilled between the high pressure and bleed channels can cause problems in the valve body with fluid state changes, temp changes. Some will never have a problem other will tear themselves up.
 
Thanks

well A new valve body and jmod could be easier than trans change. I also didn't want to pull this trans with unknow issues if I decide to freshen it up later.
 
Does this sound like a speed senor going out. It seams like a electrical issue not so much a mechanical failure. Any ideas.
 
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