on my GM truck cold 1-2nd 20MPH 2-3rd 30MPH.. goes up to 3KRPM.. 4K must be a pressure / fluid flow problem ..have the transmission shop do the pressure testing when it is cold.. or change the fluid/filter see if it improves .. when I converted to synthetic the upshifts and reverse engaged much faster ..the cold temp delay did not change because of the PCM program ..normal up shift on my GM truck and runner is the same 1-2 12 mph 2-3 around 20 MPH ..

The delayed shifting out of 2nd into 3rd is normal when the engine is cold. It supposedly has something to do with the emissions.

Your truck should always shift out of 1st gear into 2nd no matter how cold it is outside or how cold/warm the engine is.

Since your truck shifted when you manually did it, that is a good thing. When I tried this test, it still wouldn't shift into 2nd which meant there was something mechanically wrong with my tranny.

I would drop the pan and bench test your solenoids next, specifically the one that controls the 1st to 2nd shift. If you have access to the FSM, find the page that describes the three tests for the solenoid and perform those tests.

If the solenoid fails any of the tests, I would replace it and probably the other two while you are in there.

If the solenoid passes the tests, there is probably something wrong with your valve body, pump or ??? and you're better off taking it to a tranny shop at this point.

There are some other tests that you can do (line pressure etc) if you have the right equipment/tools. This will tell you if the pump is working correctly. I unfortunately didn't have these tools so I opted to call it quits and just swap in a different tranny.

Okay, so I have a different problem than you then but with similar symptoms.

Im thinking it might be the solenoids, since when I unplugged them, the truck shifted. Ill look into how difficult it is to remove/ swap the solenoids. Luckily, I have another car I can take to work, so no rush. But it sucks because I bought this rig specially to take on road trips and stuff, and this issue doesn’t inspire confidence in me.

After the solenoids ill do the filter and have a shop I trust do the fluid flush and put in synthetic.

Thanks again for everyones help troubleshooting.


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It's very easy to drop the pan. Remove the dipstick (one bolt) and remove the bolts that hold the pan on and it will drop out (drain it first obviously).

Once it is out, there is only one bolt that holds each solenoid in place if I remember correctly, you cannot miss them. I would just order a new set of solenoids and swap them in.

If money is tight, you can try testing them before you buy new ones.

And if you can change your oil, you can do the full fluid exchange yourself. It's super easy . I like to use Valvoline maxlife full synthetic ATF. Walmart sells gallon jugs of it for cheap, I would get 3.

Tim/Sean have an excellent video on youtube showing you step by step how to do the fluid exchange.