2006-08-31 14:05:44 · 13 answers · asked by Nin N 1 in Cars & Transportation ➔ Maintenance & Repairs
There are servos and accumulators which have to fill with fluid to operate the transmission. There then has to be enough fluid left in the pan to provide proper supply, lubrication, and cooling. If the fluid gets too low it can suck some air and it won't shift properly, and could slip and damage the transmission. If you check the fluid when it is not running, it will appear that it is overfilled! For more info on how automatics work, check out my website: http://econofix.com/atrans.html
2006-09-04 12:42:49 · answer #1 · answered by econofix 4 · 0⤊ 0⤋
Because the fluid in the transmission needs to be warmed up, and the pump running on it, to circulate the fluid throughout the system, which in turn gives you a more accurate reading. With the engine off, some fluid will settle in the pan, making it look like you may have more than you should.
2006-08-31 14:10:49 · answer #2 · answered by Silverstang 7 · 0⤊ 0⤋
i own a repair shop,,and this has been the way you check transmissions for years,,when the transmissions were designed ,,this was the method they used to make sure they were full,,if you check it any other way,,it will either read,,too much in it,,or not enough,,about the worse thing you can do for one is over fill it,,you can actually run one a little bit low ,,and not hurt it,,but over fill it,,and it will blow,,out all the seals in it,,it should also be at operating temperature to do this,,good luck with it,,i hope this help,s.
2006-08-31 14:17:26 · answer #3 · answered by dodge man 7 · 0⤊ 0⤋
As with most hydraulic systems(there are exceptions), the correct level is measured with the fluid at operating temp and circulating. What you are actually measuring is the reserve fluid in the sump. This reserve is designed to allow for sufficient fluid to keep the suction port submersed under all operating conditions and storage for the cooled fluid from the oil cooler. Hydraulics don't like heat, so it's important to keep enough clean/cool oil available for proper operation.
2006-08-31 16:41:02 · answer #4 · answered by Imerc 3 · 0⤊ 0⤋
The tranny fluid needs to be circulating through the tranny. When the engine is shut off, some fluid drains back into the pan and gives a false, over full, reading. It also needs to be at operating temperature because the fluid expands as it heats up.
2006-08-31 14:10:48 · answer #5 · answered by monte 6 · 1⤊ 0⤋
Some manufacturers differ in whether the engine is running or not. Consult your vehicles' owners manual. Link below for generic description on what to do.
Doing your part on maintaining your vehicle will save you money down the road.
2006-08-31 14:14:12 · answer #6 · answered by Anonymous · 0⤊ 0⤋
it needs to be circulating through the system in order to tell if there's enough. when the car is off, it's just sitting in the bottom of the pan.
2006-08-31 14:11:54 · answer #7 · answered by Anonymous · 0⤊ 0⤋
when the car is running the pump is turning that makes sure that the fluid is in valve body.so that you get an accurate reading.
2006-08-31 14:10:51 · answer #8 · answered by Anonymous · 0⤊ 0⤋
The same reason you turn it off to check the motor oil: Because that's the way it's done...
2006-08-31 14:11:18 · answer #9 · answered by KnowhereMan 6 · 0⤊ 1⤋
it should be warm for a correct reading and the pump will be pumping to all chambers.
2006-08-31 14:09:43 · answer #10 · answered by Anonymous · 0⤊ 0⤋