Issues after transmission swap

thatsnninety5

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The transmission swap I just finished up went perfectly, the transmission is good, it goes through all the gears etc. While driving nothing is wrong but when I start it up and put it in R, D, 2 or 1 the car likes to die, park and neutral it is completely fine. As I come to a stop, unless the car is put in neutral as I'm waiting for the light to turn green it will die. How I have to prevent it from dying is throw it in drive and hit the gas, same thing with after start up, I've been told it has to do with the torque converter but I really don't want to completely take my transmission out and put it back it. What are some possibilities it could be?
 

r3dn3ck

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Did you disconnect the battery at some point? If so that reset the PCM and it may still be learning. When I reset mine with the factory tune on it, it dies just as it comes to a stop with clutch in and brake depressed until it finishes the low speed drive cycle. You may have a sticky IAC valve or a massive vacuum leak too but I suspect it's not those things.

You'll want to detail the important mods, year/trim level, etc... anything that might be helpful.

If it's the tq converter, then I would be very interested to know the mechanism by which that's affecting either the fuel, air or spark delivery at idle. Until then, I'm putting my "don't know enough about auto trans to say but skepticism light is blinking" hat. I guess it could be shutting off the IAC completely but still, skeptical.
 
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thatsnninety5

thatsnninety5

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Did you disconnect the battery at some point? If so that reset the PCM and it may still be learning. When I reset mine with the factory tune on it, it dies just as it comes to a stop with clutch in and brake depressed until it finishes the low speed drive cycle. You may have a sticky IAC valve or a massive vacuum leak too but I suspect it's not those things.

You'll want to detail the important mods, year/trim level, etc... anything that might be helpful.

If it's the tq converter, then I would be very interested to know the mechanism by which that's affecting either the fuel, air or spark delivery at idle. Until then, I'm putting my "don't know enough about auto trans to say but skepticism light is blinking" hat. I guess it could be shutting off the IAC completely but still, skeptical.
Yes I disconnected the battery during the whole process. I hooked the battery back up and started my car forgetting to plug in up stream o2 sensors but shut it back on and then plugged them in but Im not getting any codes or a CEL. The car only dies when coming to a stop or going from park/neutral to reverse or drive UNLESS I instantly give it gas then itll go and wont die, but the moment I come to that stop itll die unless put in neutral. I have no vaccum leaks or anything because in park/neutral it idles completely fine like nothing at all is wrong. If Im going downhill and put it from neutral to drive it is completely fine and doesnt die, essentially giving it a “push start” such as pressing the gas as soon as it is put in gear or already moving and it going from neutral to drive, there is no issue.
 
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thatsnninety5

thatsnninety5

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So this morning, I actually notice that when I am coming to a stop I can kind of hear the sound of the torque converter cling off the flywheel, best way I can describe the noise is if you are rotating your engine to get the nuts on all four studs of the torque converter and you move it slightly to hard and the studs kind of cling off the flywheel because there is no nuts and it has "play", is it possible that the nuts just aren't tighten down enough causing unevenness/play or something of that sort so at low RPM's it gets off balance causing the car to die and at high RPM since its going so fast it essentially balances itself out, making it possible for me to drive?

Edit: Also one more thing, I jacked up my rear end, put it in drive and it did not stall, but once it was on the ground as soon as I put it in drive it drives, essentially I am saying that when there is no load/weight on the car it does not stall and all of this leads me to torque converter, but what went wrong within the swap? Bad torque converter maybe? I wanted to use my old one that I knew worked but it had the contaminated fluid in it and no screw on it to drain the fluid so I refused to use it.
 
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thatsnninety5

thatsnninety5

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Before I did the install I called a transmission shop and asked if I should fill the torque converter with fluid before installing, he told me that I shouldn't because fluid will make its way to the torque converter but from doing a quick google search I am seeing all of these things saying I should've filled the torque converter before installation. Could the issue be not enough fluid in the torque converter? Should I have prefilled it before installation?
 

r3dn3ck

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I suppose there could be an air pocket which would spread out to the full circumference while it's rotating, but I couldn't tell you if it'll blow the bubble out on its own or if that's liable to cause any issues. The pinging sound should be dealt with before you do any more troubleshooting.
 
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thatsnninety5

thatsnninety5

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torque converter is all the way in locked in
if it is not all the way in shift problems, stalling can happen
Is it possible that my torque converter is locked up and wont become unlocking causing the car to stall out?
 
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thatsnninety5

thatsnninety5

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Is it possible that my torque converter is locked up and wont become unlocking causing the car to stall out?
I looked up "can torque converter affect idle" and this is the answer it gave me "Can a bad torque converter cause a rough idle? If the car is in neutral, no. If it's in drive and the lockup part of the torque converter isn't disengaging or only partially so, it can lower the car's idle to the point it gets rough but also cause the car to creep forward much more forcefully than if it was unlocked" What are some tests I could do to see if the torque converter isn't coming out of the lock position? What that says is exactly what is happening, p/n everything is fine but coming to a stop in D, it is a rough idle until the car just dies.
 

r3dn3ck

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Sounds like you're going to have to pull the trans and redo the TC install. Bummer drag, man. At least it's only annoying and not a gigantic mess like I'm dealing with (intermittent low voltage in downstream O2's).
 
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thatsnninety5

thatsnninety5

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Sounds like you're going to have to pull the trans and redo the TC install. Bummer drag, man. At least it's only annoying and not a gigantic mess like I'm dealing with (intermittent low voltage in downstream O2's).
So my friends step father has a shop, I went there today and he hooked up his scanner, we did some live tests, it said nothing was wrong with the torque converter but what I found was really weird was “1” read first gear “2” read second gear. “D, N, R, P” also was reading first gear. After some feeling around my VSS was loose, not only at the plug but also in the trans, so we took it out, used some electrical parts cleaner and out it back in and tightened it all the way, I still have the rough idle and stall when coming to a stop in “D” but after doing that with the VSS is decreased it dramatically.
 
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thatsnninety5

thatsnninety5

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Reset the PCM again (disconnect the battery for a minute). It may have just learned unhelpful things due to the VSS issue.
I let the PCM learn, and lone behold everything works now, all along it was that VSS, just had a little dirt and stuff and wasn’t connected right, but all is good now, appreciate you for the intel.
 

RAU03MACH

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sorry late reply
check all vacuum lines one the engine that will also cause some of the problems mentioned .
 

RAU03MACH

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shift solenoids in valve body will do that well
let the computer learn and try that test again to see if it will clear
 

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