Журналист Car Talk диагностировал причину сложностей с переключением передач у грузовика Dodge Ram

Dear Car Talk: I have a 2005 Dodge Ram 1500 pickup truck with a 6-speed manual transmission. I love jamming gears, and the transmission works like a dream … most of the time. During the summer heat, when I run the AC, it gets hard to shift, especially into Reverse. I have actually been caught/stuck in a parking lot where I could not shift into Reverse gear, and had to recruit a few folks to push me backward until I could make the turn and drive away! Any ideas about what is happening to my tranny? Grateful for any advice. — Paul Shifts like a dream? If you have recurring dreams about getting stuck in parking lots, Paul. I think your clutch master cylinder is failing. That's the pump that sends hydraulic fluid, under pressure, to the clutch to make it disengage. If the clutch won't disengage, it's hard to shift. Reverse is the hardest gear for the truck to shift into, because an extra gear is needed to reverse direction. So, if the master cylinder is failing, that's the gear in which you'd first notice it. If you want to test my theory, wait six months and see if you can't shift into first gear either. And here's why it fails first in hot weather: The master cylinder uses a piston to push hydraulic fluid to the clutch. That piston has a rubber or rubber-like seal around it. Sort of like a toilet plunger, but much more expensive and slightly less disgusting. If that seal starts to wear out, fluid can sneak by it, reducing the pressure sent to the clutch slave cylinder. And when the engine compartment gets really hot, that seal gets softer, which lets even more fluid sneak around it. At some point, it can no longer send enough pressurized fluid to disengage the clutch. Add to that the tendency of fluids, including clutch fluid, to get thinner when they heat up. And you've eventually got a situation where you can't shift. There are other things it could be, Paul: bad synchros, low or filthy transmission fluid, or a clutch itself that's failing. But my first guess would be that you're a candidate for a new master cylinder/slave cylinder combo. So start dreaming about putting $600 on your credit card. Got a question about cars? Write to Car Talk write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.