How to change auto transmission filter?

Thanks for checking. I guess I'll just try a regular flush and see if that helps my shifting issues.

I'd also like to check the throttle position sensor, but can you provide any tips on the procedure? Do I leave the TPS in place, but just detach the electrical connector to tap into the TPS wire connectors? What values should I expect to see when pressing the accelerator petal with the TPS hooked up to a voltmeter?

What other sensors should I check (and their normal values?) As possible causes of transmission shifting issues?

Thanks!

I suppose slipping is what it is. I should also add that the last two days coming to work (7am) it had NO issues whatsoever, but on the way coming home from work around 3:45pm (when it's more like 75 degrees or so) it starts happening about halfway home, so around 20 minutes of driving (about 10 minutes of that is freeway). So now I'm wondering if the issue only happens when the trans gets hot.

To explain exactly what's happening: it will be shifting just fine on surface streets and getting on the freeway, and I'll be crusing along around 65-70mph at the most, then suddenly the rpm will go from around 2700 up past 3000 (a few times as high as 3500), then the trans will***** back into gear very roughly. Then for the next 10 minutes or so on the freeway it will randomly raise the rpm's and***** back into gear. Sometimes it will do it several times in a row, and sometimes not quite as rough, rasing the rpm's only a little before******** back into gear. It seems to start happening when I'm crusing at a steady rate, but then I do lower my speed once it starts happening to make sure I'm in as much control as possible, and over in the slow lane.

There's no way I can afford $1,000 and upwards in transmission work, so I'm hoping to exaust all other possibilities, especially things that I can test myself.

Oh, almost forgot, I checked for codes about a week ago and there were no stored codes and no pending codes, but I'll check again since more time has gone by now. But still no check engine light to indicate stored codes. I also have the ability to view live data, in case you have any suggestions in that area.

Thanks so much for your help, I really appreciate it!

I guess I should add that I just drove it for a short outing, all streets, no freeway, and keeping to 40mph or so, and had some slipping. I suspect I was at operating temperature by the time I got to where I was going, and barely over idle in the parking lot it was slipping in first gear, not in gear change or anything, just barely over idle in first gear.

Do you know of any way that I can access diagrams for this transmission?

Also, I'd like to find out how the trans cooling lines are routed and I'd like to try flushing out the lines. I may also want to install a separate trans cooler unit.

I realized that the issue was only happening if the engine/trans was hot. The issue stopped for two days when I tried my drive home (warm afternoons) with the heater blower on high, but the 3rd day the issue was back the same, except it may have started a little further along my drive home (actually started at pretty much the exact same place on the freeway the last two days in a row).

Thanks again for your input!

Hmmm, both good ideas. HF is my favorite store anyway. I was just there yesterday in fact. I can always use an excuse to make a trip there.

Would I just point the pocket thermometer laser at one of the trans cooler lines?

Any possible adverse affects to removing the thermostat? (I know it is only temporary)

Thanks so much. You're awesome!

Removed the thermostat, but that had no affect on the shifting issue.

I did see some advice on the web about the "selector lever position sensor" (aka: transmission position sensor, manual lever position sensor, etc). The advice was to check the voltage in each position: P-R-N-D-2-1

Aparently the voltage at park is supposed to be 5, I'm getting about 4.6

In "D" it's supposed to be 2.2-2.4, I'm getting 2.13 volts
That is pretty close, so not sure if I should think anything more of it, but what do you think? (Voltage for all other positions were spot-on to what they were supposed to be, so only P and D were a little off)

I also got a suggestion from someone to watch this sensor data while driving while the problem is happening, but my scan tool is too generic and it does not show this sensor, so I'm thinking about leaving the leads hooked up to the sensor and running them out of the hood and into the car to watch my DVOM while the problem is happening.

I will still pick up the digital thermometer to verify the trans temp also, but have not done so yet.

Just to give an update. The problem is now fixed. I watched the voltage on the "selector lever position sensor" (parts store had it listed as a "neutral safety switch") and it fluctuated quite a bit while driving. It is supposed to be 2.2-2.4 volts in "Drive", but it would move all around that range on surface streets an on the freeway, even before the shifting problem was happening, rather than staying at a consistent voltage. Then when the shifting problem started several miles into my freeway driving, it was spiking up well above the 2.4 voltage range, and at one point it was as high as 4.9 volts. After seeing that I felt okay about swapping out the part since I had some evidence to go by.

It has been a few days now and I have not had one shifting problem since.