berthapegues Posted June 4, 2010 Report Posted June 4, 2010 I have a lot of questions about buses. 1) When a bus is sitting with the retarter activated for at least 5 minutes, and once you press the gas pedal, why does the transmission gets stuck ? 2) When parking brake is applied and you don't shift it into nuetral, why does it get stuck even though you didn't shift gears ? 3) Why does Fast Idle makes a bus NOT go into gear ? Quote
sw4400 Posted June 4, 2010 Report Posted June 4, 2010 I have a lot of questions about buses. 1) When a bus is sitting with the retartder activated for at least 5 minutes, and once you press the gas pedal, why does the transmission gets stuck ? Presuming the retarder is the lift/ramp. It can be any number of things... see "Breakdown Thread" about #1422 for an interesting breakdown story involving a bus that just wouldn't move anymore. If the retarder is not the lift/ramp, than I haven't the slightest idea... 2) When the parking brake is applied and you don't shift it into nueeutral, why does it get stuck even though you didn't shift gears ? Again any number of things could be the cause... like my Father used to say about solving a mechanical issue with a vehicle... S.S.F(simple s##t first) Start with the most likely causes and go from there. 3) Why does Fast Idle makes a bus NOT go into gear ? Quote
rmadisonwi Posted June 5, 2010 Report Posted June 5, 2010 First, a bus cannot "sit" with the retarder activated. The retarder uses the engine/transmission to slow the bus down. Depending on the design and spec of the bus (often, customer options), the retarder will usually activate when the driver takes his/her foot off the accelerator pedal. The retarder disengages just before the vehicle comes to a complete stop (this is the air discharge sound that some of you go nuts over on the Allison transmission New Flyers, 1930-2029, just before the bus comes to a stop). If a retarder is active for five minutes, something has seriously gone wrong, and the transmission getting stuck is probably the least of your worries. How the bus handles shifting/parking brake application is a customer-specified option that is controlled through the vehicle's computer. In general, though, there are safety features in place to prevent a bus from rolling away. For example, if the parking brake is accidentally released, the bus won't move right away without the bus being in neutral and then placed into drive. 1 Quote
berthapegues Posted June 5, 2010 Author Report Posted June 5, 2010 OK, I'll put it like this. If a bus just sits and your foot is off of the break , why does the transmission get stuck ? Quote
berthapegues Posted June 26, 2010 Author Report Posted June 26, 2010 Okay, what about runs ? Like what are part time runs, full time runs, swing (Split Shift), and block runs ? What run requires a relief and pull out/pull in ? Quote
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