Your car stalls out when you put it in reverse or drive is the transmission?

It's highly likely a transmission problem, but not definitively so. A car stalling when you shift into drive or reverse could indicate several issues related to the transmission, but also problems elsewhere in the drivetrain or even the engine's electrical system. Possible causes include:

* Transmission problems: Low transmission fluid, a failing torque converter, worn-out clutch packs (automatic transmission), or internal transmission damage are all strong possibilities.

* Driveshaft/Axle problems: While less likely to cause a complete stall, a severely damaged driveshaft or axle could put enough stress on the transmission to cause it to stall.

* Engine issues: A problem with the engine's ability to generate sufficient power (e.g., failing ignition system, fuel delivery problem) could cause a stall, especially under load when shifting into gear.

* Electrical problems: A faulty neutral safety switch (prevents starting in gear) or a problem with the vehicle's computer system could interrupt the power flow to the transmission, causing a stall.

You need a professional diagnosis. Trying to troubleshoot this yourself could be dangerous. A mechanic can properly diagnose the problem by checking transmission fluid levels, inspecting the transmission, and performing other necessary tests to pinpoint the exact cause.