2-3 Shift Flare
 

My 14 month old transmission rebuild is flaring on the 2-3 shift again ... I really don't want to do the transmission again - only 12,000KM on rebuild! Hopefully it is something else. I've searched posts and see things about TPS and a solenoid behind the battery. Can anyone get specific on these things for me? Where do I find the TPS? Is it something I can test/adjust/clean? How about the solenoid - exactly where is it and is there anything else near it that might confuse me or cause problems if I make a mistake? Does bypassing this solenoid put anything at risk? You can tell I'm a little nervous but any help is appreciated - thanks! :)

Look in the How-to locker for instructions on how to test the TPS.

The resistor behind the battery should normally measure around 10-12ohms. The replacement I just installed measured 12ohms. Without the resistor every shift is at FULL line pressure. In other words the resistor will smooth each shift.

How large is your flare?

That sound's a little personal does'nt it?:D

Can't we be curious? :D

Is the tranny still under warranty? I would replace it now if it is.

I bought mine with 100k and it had a small flare at very light throttle. I would guess that it revved up 3-500rpm between shifts. It only happened at low speed and light throttle. I unplugged the resistor and ran another 57k miles with no problems. I adjusted the TPS a few times during this period and did notice that even with the resistor plugged in I could get rid of the flare with a little adjustment but then the car idled very low and sometimes needed a foot on the gas to start. This may be due to an erratic signal from the tps at off-idle throttle but I only used an analog ohmeter to test it so I'm not sure if the erraticness is the tps or the test method.

When the flare finally reappeared without warning at 157k it was the end. The tranny lasted about another 2 weeks of very slow driving and manual shifting. The car would somtimes tach up to redline between shifts and then slam into the next gear with a nice gut wrenching screech. With the torque converter locked up I could step on the gas and make the tranny slip. I adjusted the tps, put in a new tps, plugged in the resistor, unplugged it, swapped out the TCU, changed the fluid. None of these helped.
This was the dreaded 2-3 flare everyone had talked about. Completely different feel than the little over-rev I had before.

Had the tranny shop that did my rebuild go over the tranny again. Biggest problem is that the flare is not consistent - doesn't happen every day - and they couldn't duplicate it. They played with the TPS and checked all other electrical systems, fluid pressures, etc. and everything came back fine. Good guy though - agreed to warranty me 6 more months (actually expired) to watch for worsening problems.

BTW - tried disconnecting the resistor and did not like the way the transmission shifted at all - very abrupt especially on the down shifts. Plugged 'er back in right away! Also, to answer the question - the flare is typically 1-2000 rpm when it happens.

I guess we'll see if time brings on new problems or if the TPS adjustment made the difference - haven't had a flare since . :)

If the flare is at those lower RPMs (only) then I think it must be the TPS (right, svx_commuter? :) ) I took mine off to clean but it didn't seem to make much difference; I should probably soak it in contact cleaner (instead of just spraying it in) and maybe readjust it. The easy thing to do is just drive, keeping the RPMs right around 1800-2000 under acceleration (seems to be the best range for a better 2-3 shift anyway)

Popps,
Sounds like you're going down the same road I did. Rebuild, then, six months later, flare. They replaced the TPS (I paid for it, but they didn't charge for labor). About six months later, 2-3 flare again. 31 Days later, after changing solenoids, checking resistor, etc, etc, they dropped it and rebuilt the high clutch. Less than six months later, I start getting duty Solenoid C codes and my AWD locks into 50/50. I'm reluctant to take it back in, for fear of waiting another thirty days for diagnosis.

Beav recommended I try substituting another control unit. I did. I now have a permenant replacement and the car's running like new. So, if problems continue, try finding a used TCU. It may be your problem.

Probably valuable advise given what you've gone through - certainly don't want to have to duplicate your whole experience! If things go bad again, I will certainly try the TCU route - thanks!