Skip the auto shop - Our mechanics make house calls

Q: Why does my truck only change gears once while driving down the road?

asked by on

Hey I have a 2003 Chevy s10 and the transmission is acting up on it, it only changes gears once while in drive going down the road at about 45-50 then it won't shift past that it will go to 70 and then top out when it does change the gear the one time it doesn't jerk or slip a couple people told me it could be the modulator valve but idk any ideas
My car has an automatic transmission.

Hi and thank you for your question. Your transmission issue sound like that there is an electrical issue within the transmission. If you are not feeling any shifting, that is because the transmission computer unit has put the transmission into fault mode or limp mode. This will allow the transmission to start out in first gear, but it will shift directly to third gear only.

The shift packs in your transmission directs fluid through the transmission to activate the gears second and fourth. First gear and third gear does not need the shift packs. Most likely the shift solenoids have overheated and failed. Also, the throttle position sensor could cause a delayed timing of the transmission to shift.

If you do not have 2nd gear, 4th gear, or reverse, then the Sunshell inside the transmission has broken or the splines are stripped. If replacing the shift solenoids and the TPS don’t fix the issue and if the transmission has the reverse gear, then the modulator valve body (valve body assembly) needs to be replaced. If you need assistance troubleshooting this issue, a certified professional from YourMechanic can come to your car’s location to inspect the shifting problem and advise on the repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • Why does my truck only change gears once while driving down the road?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: RPMs issue - 2012 Hyundai Veloster

Hello. This sounds like your clutch is slipping. Check the transmission clutch to see it is slipping and needs to have the clutch replaced. If you would like to have this looked at for you, an expert technician from YourMechanic...

Q: What would cause my transmission not to go into 1st gear and not down shift

Hello. I will help you with your question about the transmission in your Chevrolet S10. There are both electronic and hydraulic shift controls in your vehicle. A likely cause of the failure to shift or downshift is a valve in...

Q: Shudder from a WOT at about 20-25, now the OD light blinks, shifts hard from 1st-2nd and 4th-5th

Based on the information you provided, you certainly have a transmission or torque converter issue. A flashing overdrive light could be an indicator that the torque converter clutch is not working. That can be due to a bad solenoid or...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...