Check trans fluid.
Check computer codes.
Probably shift solenoids going out. 18.00 fix, plus work.

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Thanks for the quick reply Shrimp18dog. I checked the trans fluid last night and it was up to the proper level and seemed to be reasonably fresh (wasn't dark and had no smell). I'll see about getting the codes checked this evening. Is this something I could expect the free scanner at AutoZone to detect, or is this something I'd have to have a certified mechanic check on?

I'll look into the shift solenoids, thanks for that.

 

Moved to Transmission/Rearend.

 

No problem. Any of the auto parts stores can check the computer codes for free. A lot of time, they can order the part, show you a video on replacement. I change both, 1&2 and 3&4 in mine .
Not too hard.

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Your truck is right at the correct mileage when most transmissions in these things go out. Sounds like yours is toast.
Any 98-04 4wd S10 (not full sized) 4L60E will interchange. The broadcast code needs to be xTAD. x being the year. Yours is a 3TAD.

 

have you confirmed its not a TCC problem?
while cruising lightly step on brake pedal and see if RPMs increase.

 

I tried that dime-dozen, and didn't see any increase in the rpm's when I stepped on the brake pedal.

The problem went away completely for a couple of days, then it started back today.

I'm going to go ahead and change out the filter, fluid, and all three shift solenoids. Couple of questions for you:

When looking for a filter, the places I usually order parts from specify a shallower (2-1/4") or a deeper pan (2-7/8"). Is there any way to tell which one I need without getting under the truck and trying to measure the depth of the pan?

Also the descriptions of the shift solenoids are all over the board as well. Some say they are replacements for the 1-2 and 3-4 solenoids, some say they are for the 1-2 and 2-3 solenoids, and some say for 1-2 and 2-3 and 3-4 solenoids. I was initially under the impression that all three solenoids are the same. What is the truth here?

 

When looking for a filter, the places I usually order parts from specify a shallower (2-1/4") or a deeper pan (2-7/8"). Is there any way to tell which one I need without getting under the truck and trying to measure the depth of the pan?

I'm not sure if you figured this out yet. The two pans are definitely different visually. The deep pan has a "step" in the bottom.
Shallow pan:

Deep pan:

 

A few things. The 2003's had "tow/haul mode." Did you trip that somehow? There will be an amber light on the dash. On the full sized trucks, it looks like a trailer. Not sure what it looks like on the S series. That mode disables the Torque Converter Clutch and changes the shift strategy to use lower gears longer.



Also, if your thermostat is sticking open and the thing is running too cool (or if someone put a lower than stock thermostat in the engine), it won't lock the torque converter clutch until the engine is fully warmed up. With a stuck open thermostat, it may never activate the TCC.

 

Thanks for the response Racer-X.
This one doesn't seem to have a Tow/Haul mode. I just checked again and can't find any buttons for that feature, and there aren't any lights on the dash that indicate that it is active. I've had that feature in other trucks so I know what you mean.
The temp gauge on this truck isn't working, so I can't prove that it is getting up to operating temperature, but it isn't just that it isn't going into overdrive, it won't shift all the way down to first gear, and you get random fluctuations between second and third while cruising as well. And it seems to work fine for the first few minutes of operating, but starts to act up after it gets warm.

 

1. Check fluid level with engine running and at full operating temperature. Run the gear selector through each selection just prior to checking fluid level.
2. Check for stuck open thermostat as Racer-X said
3. Check for codes
4. Does it have a K&N (or similar) air filter? If oiled excessively, the oil can get on the MAF sensor and this can cause shifting issues. There's service bulletin from GM regarding this. I would just clean the MAF sensor using MAF sensor cleaner regardless. Dirty MAF sensors do weird things.
5. Check for a plugged up trans filter
6. If the problem persists, do a line pressure test. That would point you in the direction of the problem

To me it sounds to me like you have a pressure control solenoid that is failing. If that is the problem, I would replace all the solenoids (there are 5 of them total). A 1-2 shift solenoid, a 2-3 shift solenoid, a 3-2 control solenoid, a TCC solenoid and a Pressure control solenoid. When one goes the others usually aren't too far behind it.

 

too late to edit my last post. Where I said it sounds like you have a pressure control solenoid that is failing... I meant it sounds like the solenoid (or the associated valve in the valve body) may be sticking.

 

I just read the temp gauge isn’t working. That would be the first place to look as the PCM uses engine controls to schedule shifting. Just a few, TPS, MAF,ECT. If it’s not getting seeing the right info it will inhibit shifts and put transmission in failsafe mode. Good luck
Brad

 

with so many things interlinked to each other its almost worthy of a PSA to say that all codes and problems need to be fixed then move on to the next. Everyone of us is guilty of talking ourselves out of a ,no that problem isnt related,thing when in reality it could very well be.I had a temp sender go flaky(intermittent ) and it would stall the motor out because the fuel couldnt adjust fast enough. That problem alone saved me about $800,as the car lot it was sitting on had given up trying to figure out what is was.

 

We're all guilty. Nice to have a trans expert around to point out obvious things the rest of us overlook.

 

I would rebuild/replace trans. Mine started acting up at 125k. I rebuilt it but reasonable from $1500 up and get new converter clutches toast by now. Jtc,1133