2007 chevy colorado. Auto Transmission clunked during a couple of shifts then will only drive in second gear. Limp mode?? Has reverse, will drive in 1, 2,3, and d but in second gear. Got codes checked came out with gas cap code. Changed gas cap. Still only drives in second and wont shift up. Any thoughts of a diagnosis? We live in the country and a tow is expensive!!!! Thanks, tj

Sounds like it is stuck in second gear. Overdrive only drops rpm by a couple hundred. In third gears you should still be less than 3,000 rpm.

Second gear is a default gear when the transmission is in limp mode. Is the check engine light on? Does it shift if you manual shift through the gears with the gear selector?

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sounds like it is stuck in winter mode

Start with shift sensor. Then go down the line. It is possible something went wrong during the last shift and the transmission sensor locked it down into safety mode to avoid ripping up transmission. If this doesn't fix it you may need a rebuild.

Of course the first thing to do is to check the transmission fluid level. Next have car scanned for codes, if there is a speed sensor malfunctioning, the transmission would go into limp mode. In limp mode, only reverse and second gear work. Many auto parts stores will scan your car for free. I hope this helps.

That's called "Limp in Mode" Something in the transmission has failed. You may have lost 3rd gear, or reverse, or some other problem. The TCU (transmission control unit) has detected a fault, and has put the tranny in to 2nd gear. That way you can still drive it to the local dealer so they can repair it. Limp in mode keep you going so you don't have to have it towed. However, since it is only second gear, you won't want to drive very fast, probably no more than 30pmh, and you will want to get it checked out as soon as you can. Could be something as simple as a sensor failing or coming unplugged, or an internal failure with one of the bands, servoce, solenoids, or bands or clutch packs.

When you start it up and drive it the next time, pay close attention to how it shifts. Does it instantly put you into limp mode (First gear failure) or when it tries to shift into 3rd, and then put s you back into seond for limp more. this information will be important in getting an estimate. I appologize for any typpos here, as this form is not letting me see what I am typing.

Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmision is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the underhood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.
What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.
Before guessing at transmission problems, check the fluid level (car warmed up, engine running in Park on level ground) and have the PCM scanned for trouble codes FIRST. This guide is meant for problems that do not show up as PCM codes (like shift A&B solenoid failures, for example).
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Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmision is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the underhood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

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Your transmission is in a "limp in" mode. There are 2 sensors that need replaced. Total cost should be less than $100. I had it happen to me on my 99 300m. The sensors limit the speed to about 25 mph and the RPM rev's high. Just get the sensors replaced.

If check engine light is on ,remove battery cable, you have an electrical problem, maybe fuse?

eric sounds like you have a electronic trans mission or computer controled trans.is the check engine light on ?

second it sounds like your trans is in limp in mode ( only has second gear).

the hard shifts is not good news.

somtimes when the controller sets a code that forces limp in it has to be cleared.

dis-connect the battery for a few min. then try it again see if it shifts but be easy on it and make sure fluid level is good.

if it it still messes up CHA CHING hehe i'll fix it fer 1000 bucks