your clutch is probably shot
When the car stalls out, depending on speeds, you can strip part of your transmission. (Basically break the tranny). Most stalls are stripping and what not when it comes to stalling, also I'm pretty sure you can short out some of the systems inside the vehicle.
IF IT IS A MANUAL TRANSMISSION CAR, THEN IT SOUNDS AS IF YOUR CLUTCH IS BAD/WORN OUT.
A car might stall when shifting from park to reverse if the idle is set too low. It is also possible that the engine stalls because it is not fully warmed up before shifting from park to reverse.
Having trouble with it stalls?
try the converter lock out sensor in the transmission
it sounds like your tcc (tourqe converter clutch) switch is faulty. this is a common gm problem.
This is a similar problem I had with my '91 Lumina APV. The problem I had was the transmission overdrive lockout switch. These trannies use an electro-hydraulic lockout switch to hold them in overdrive, but if the switch is malfunctioning it won't allow the transmission to downshift, so when you come to a stop the car stays in gear stalling out the engine. It's like stopping without using the clutch and not down shifting in a manual transmission car. The interim remedy for mine was to disconnect the switch from the transmission, then I sold the vehicle to escape the costly trans repair. Disconnecting the switch keeps the trans from shifting into overdrive, so you wouldn't want to do a lot of highway driving with the switch disconnected. Good luck!
You'd have to clarify the question. What you're asking may be a moot point, anyhow - if you're driving a trash collection truck, you're going to have something like an Allison five or six speed automatic, and really tall rear end gears, anyhow. Now if your garbage truck is something like a Ford F750 single axle truck or similar, and it does have a manual transmission, it'll be a synchronised manual transmission, which you drive just like you would a regular passenger car transmission. You really don't have to worry about hitting your RPMs just right with one of those, nor double clutching - you just have to ensure you shift before your motor either bogs down and stalls, or else redlines.
If it's an automatic, you may have a sticking solenoid INSIDE the transmission.
Put shifter in park or neutral.
Torque converter staying loced on transmission change solenoid
If it is a transmission problem- First step would be to change trans. fluid and filter If it is a transmission problem- First step would be to change trans. fluid and filter