Transmission Help

[Maidioso]

u eva heard of a transmission that switch between automatic n manual?

what is this called? thanks

[public]

I have seen automatics with a "shift kit" installed so you could shift manually.

[curtis73]

Several possibles. There are new computer-controlled transmissions that are regular automatics but have alternate controls that let you bump the lever up and down. Dodge has one called the AutoStick. BMW has an almost F1 style paddle shifting on the steering wheel. Someone has one called a ManuMatic. There's another from Porsche called the TipTronic

There is a manual shift automatic like Public said. It bypasses the transmissions shift calibrations and hydraulically puts and holds it in the gear you select.

There is also a Planetary transmission used primarily in drag racing. Sometimes called by their brand name of Jeffco or Lenco, they are easily identifyable by the several large shifters sticking up through the floor. It is a stack of planet sets that keep reducing the ratio by about .70:1. Locking them all up produces a 1:1 ratio, leaving them all open makes a ratio equal to .70 times the number of planet sets you're using. If you have a five speed planetary set, your first gear ratio would be 3.50:1, about equivalent to the first gear in many cars. You start out with none engaged, then keep pulling the levers to engage each planet set. In this case, the ratios would be 3.50, 2.80, 2.10, 1.40, and 1.00.

Lencos are confusing sometimes. They are most typically set up with clutches. You use the clutch to start, but then its not necessary between gears. You let it out, accelerate, then just yank the levers in succession like a manually shifted automatic. Some can also be set up with a Torque Converter and operated without the clutch. These are operated very similarly to a manually shifted automatic and don't require a clutch to start and stop.

[MagicRat]

In addition to curtis excellent answer, there is one more: recently Ferrari has developed a traditional manual trans, complete with traditional clutch and syncromesh shifter, but it also has electronic mechanisms that can automatically operate the clutch and shifter resulting in auto performance almost exactly like a traditional auto trans.
The advantage here is that (unlike the manumatics from other manufactureres) it behaves exactly like an ordinary manual trans (because thats what it is) with an auto option at the push of a button.
Car and Driver tested one a while back, and found the auto function was flawless.

[public]

Lets not forget (i forgot earlier) the "Hondamatic" type where you must shift but not clutch. I think my fathers old Superbettle has one of this "autoclutch" type. I had one on an old Ford farm tractor called "Select-O-Speed" 10 speeds with a combo clutch/brake.