i think i have some sort of electrical problem. my truck starts hunting for gears occasionally; ESPECIALLY at night... not as often in the day time. sometimes its BAD. if i leave a light, itll go in and out of 1st and 2nd, then itll go in and out of 2nd and 3rd. sometimes, it doesnt leave 3rd and will only do about 50mph turning 2200rpms. when its only a mild problem, the TC will unlock and lock. sometimes, it might down shift into 3rd on its own and leave the TC unlocked. but, when this problem manifests itself, the truck is basically undrivable.

the problem is very prevalant at night time, but i had it do it the other day in the day time too... but only after having my headlights/high beams, blower fan, radio and guage illumination maxed out. i turned all that crap off and it didnt stop the 2nd/3rd/4th gear hunting untill i stopped and turned the truck off.

my generator is putting out about 14.7v right now. ive got the 12v but my tranny was from a 1998 truck, its not the original unit. anyways, i put the scan tool on my truck, and SOMEhow, my TC solenoid is being told to unlock and lock... so there is an electrical gremlin in there. im not sure what i should do to fix it.

i added a ground strap from my ecu to the neg batt terminal, but thats all. ive heard about the noise filter or inductive capacitor clamped onto a wire but that only seems like a bandaid thats not addressing the REAL issue of RFI noise. somehow, this truck made it 10 years w/o this problem... what does it take to make it go another 10 years w/o the hunting problem? replace the brushes in my alternator?

btw, my TPS has been recalibrated. voltage w/ throttle closed is 1.02v. the TPS voltage i recorded when witnessing the TC unlocking/locking was 1.64-1.72v with no drastic spikes. my trans temp reading and temp sensor voltage never spiked either.

how do i clean the TPS?
should i segregate the TPS wires from the main loom and apply braided sheilding?
should i apply braided sheilding to the alternator power cables in the main loom also?

i can take the wire harness off the truck if i have to... i modify engine harnesses as a side job... i just dread doing my own harness.

anyone?

 

Not an expert on this, but I would still say the TPS may still be the culprit. Use some really good quality electrical contact cleaner like Cramolin (may be available at a guitar shop). Also make sure your plug is clean and put a liitle bit of silicone grease on it. Could also be dirty (corroded) connections on the ECM. Somewhere (quite a while back) I saw a post on adding a capacitor to a "rough" TPS to smooth out the signal. You might do a search on that. Maybe somone with more experience on this specific problem will chime in.

There's also a transducer down on the VB that sends a pressure signal to the ECM. Check plugs down on the trans, etc.

 

I have had the same problem as you. Depending on where you live it might have something to do with the temp. I notived when it is below40 or 45* out the tranny searches for lock up. So I put a cardboard air dam over my front tranny cooler and it shifts fine now. I also let it warm up for a while in neutral before I take off.

I used a for sale sign and taped it over the tranny cooler only. Give it a try and see if yours does the same. I put a brand new TPS on mine and it made no difference.

 

Get the noise filter from DTT. It has fixed many of these electrical issues.
Of course, they recommend that you first clean all battery terminals.

 

I hate to sound like a complete idiot, but where exactly do you mount this noise filter? Is it off the TPS or Alt? I'm experiencing some of this hunting as well. Any help would be most appreciated.

 

It comes with instructons.
It usually is placed at the PCM by the air filter.