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Q: I might be having transmission issues but then i think it could be a engine problem.

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So i have recently received this truck for a graduation present. Before i have received it the truck had a bad transmission. We replaced the transmission however the "new" transmission we put in the truck came out of a 2004. Now the truck wont allow us to go over 40 mph because it will shut the engine down. What is going on???
My car has an automatic transmission.

Hello,

From what you describe it appears that whatever problem your vehicle may be experiencing has caused it to go into limp mode.

Limp mode is a precautionary mode where the power and speed of the vehicle are severely limited. It is activated when a major issue is detected in order to protect the vehicle’s components from sustaining possible damage.

Limp mode can be caused by a wide variety of issues including engine, transmission, mechanical and electrical issues.

You mention that the transmission was recently replaced with one from a different year.

I would first verify with a dealership or knowledgeable parts person that the transmission is in fact compatible with that vehicle, and if it is, then move on to verifying that the installation was properly carried out. Double check all harnesses, connectors, and mounts to make sure that there are not any issues.

If everything appears to be sound, then I would recommend having the vehicle inspected by a professional technician, as again, limp mode can be activated by a wide variety of issues.

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