Can you turn on and off the overdrive on a 98 ram 1500
I have never known an overdrive that cannot be switched on or off at will or engaged or disengaged.
There are two definitions of overdrive and in the philosophy of some people the fifth gear is an overdrive.
The conventional manual gearbox, because the first motion shaft is locked to the third motion shaft in the top gear ratio, any supplemental ratio that has a ratio higher than 1:1 is considered an overdrive ratio.
The more traditional definition of an overdrive is a supplementary gearbox that can be incorporated into a normal manual gearbox to provide a single overdrive ratio for the purpose of quieter and more economical cruising.
The early overdrive was cable operated by a large chrome-plated dashboard-mounted handle. Later overdrives were hydraulic units that could be switched in or out by electricity, often by the means of a steering column-mounted switch or by a tiny switch incorporated into the gearknob.
A typical installation included an inhibitor switch mounted on the gearbox which prevented overdrive operation in the lower ratios when the benefits would be dubious.
Sometimes a lower than standard final drive ratio would be used and the overdrive ratios which typically could be selected whenever third or fourth gear was selected could be used together to produce something like a six speed close ratio gearbox which was hitherto unheard of when some of the rest of the world was still using "three on the tree" type three-speed gearboxes.
Most manufacturers had dispensed with overdrives by the end of the 1970's due to the weight and added expense, in favour of the now common five-speed gearbox, though Nissan incorporated an overdrive ratio into their automatic transmissions to compensate for torque converter slip when fuel costs began to rise disproportionately.
If you have an overdrive unit fitted to your car that doesn't work, I advise starting the diagnostic process by checking through the electric circuitry, wiring, switches and solenoid.
Feb 12, 2015 |
Cars & Trucks