Eric ,


I saw you present this question to someone in 2002 as I was looking around message boards.


"First, are we talking "full lock-up" as in stomping on the binders? (A full stomp -- on the brakes -- to activate the ABS would be one extreme...)""""


When you say activating the the ABS ...what things happen when the ABS is activated ? I'd really like to know just for comparrison .


Also I would like to hear your opinion as to whether you feel that the 2nd gear of these transmission's was the real culprit for the majority of lock-up's that have occured or if the 3rd gear clutch pack could create lock-up's to this extreme.


Thanks Eric .

 

How Anti-Lock Brakes Work

ABS will stop a car in the shortest distance. A locked up transmission (front wheels bind and stop moving) will not stop a car faster than the ABS system.

 

I believe Eric may have answered this question in another thread ,but since you replied ,let me ask.........What condition's specifically ...any and all and please be specific ............ can you think of would MAKE your ABS kick in?


I no nothing about ABS ,so this would be helpful.


One more thing.........do you already have to have your foot on the break for ABS or can car go into ABS on it's own?????

 

"A skidding wheel (where the tire contact patch is sliding relative to the road) has less traction than a non-skidding wheel."

ABS keeps the wheels from skidding while you slow down. It activates when you depress the brake pedal enough to cause a wheel to skid. You have to push the pedal to activate the ABS. This link explains it all .. http://auto.howstuffworks.com/anti-lock-brake.htm

 

simple- icy patch on the road- a slight brake pressure and your ABS will kick in to keep the wheel from locking up.

edit- you floridians won't have this "problem" ! hehehehe

 

1. IMO, the 3rd gear clutch pack is the weakest link. (This from information that Acura sent to the NHTSA.) When it comes apart, it dumps material into the system. If the transmission is of an older design, it can burst the pipe strainer and cause a 5-to-2 downshift. The 2nd gear clutch pack can dump crud into the system too, but...

2. If you engage the ABS, the car will stop hard. The wheels will not lock up (this presumes that all is working correctly, etc.)

The ABS looks at wheel speed sensors to detect if the wheels are moving or locked during braking. If the wheels "lock-up," it will momentarily release the pressure to the wheel that is locked up. Cars stop best -- on most surfaces -- with brakes set to just before lock up.

If you put two cars side-by-side, and put them on a wet or icy road, the car with the ABS will stop in a shorter distance when compared with a car with its tires locked up. Some professionals like to turn ABS OFF when they are on gravel. IN pre-ABS days, it was necessary to "pump your own brakes" to get the car to stop in the shortest distance and to maintain control.

BTW, the car stopped with brakes + ABS will stop quicker when compared to a car with a "locked transmission." This is related to the wheels/tires being “locked” vs. moving. The downside of having the wheels locked is losing control of the steering. IOW, if you lock up the wheels, you are not going to be able to steer the vehicle in a predictable direction.

Finally, the reason for the better distance with ABS is: the coefficient of friction is higher when the tire is rolling.

Physics/Friction forces:

http://hypertextbook.com/physics/mechanics/friction/

 

see here http://auto.howstuffworks.com/anti-lock-brake.htm

 

If I remember correctly, the ABS light came on when my tranny did its super downshift. The ABS light would go out in a soon after, until the next event.

 

I can assure you that when my tranny did the downshift "shuffle" I certainly wasn't looking at the dashboard lights. Me, I was watching the yahoo behind me as he tried to avoid rear-ending my car.

 

The light may have come on (I wasn't there), but it wouldn't have done anything with respect to the tranny’s locking up. If the tranny is "locking up," the ABS pump would NOT play a part in diminishing the rate of deceleration caused by a transmission lock-up. It simply controls the brake pressure, and since the retarding force is from the transmission's downshift, it would have no effect.

Perhaps you hit the brake pedal too. If you engaged it in conjunction with the spontaneous downshift, it would sense the lock-up and at least control the hydraulic action of the brake system would try to alter its behavior.

And, to be clear, the ABS would NOT prevent the front wheels from locking IF the transmission locked up. For example, if the second gear teeth ripped off causing the car to lock up the front wheels, the ABS pump would do nothing. Even if the brake pedal was pushed in panic (I don't know why this would be a good idea) the from wheels would still remain locked.

So, the ABS only controls the clamping of the brake pads; it has nothing to do with the transmission's power/engine braking properties.

As mentioned previously, it would be pretty hard to know what was blinking/flashing while the driver and passengers were experiencing their "near death experience."

It could be possible to have the VSA light come on if it detected the wheels locked up with the car's yaw sensors going nuts. I don't know if it would do much since it uses the ABS pump to control the wheel lock. If they didn't lock up, it would change the "yaw" of the vehicle.

 

I didn't do the brakes after the shift. The abs and the traction control light (can't remember the letters) were on. The abs light would go out in a minute or so. If one front wheel slows during the down shift (with the brakes not applied) could the wheel speed difference activate the abs light?

 

This technical stuff totally confuses me. I do agree with the person here who states they didn't notice anything like lights ..I had a total of 8 lock-up's ...I never thought to look at dash ...The lock-ups were so severe I was in a panic .....it never occured to me ...The CAR would drive perfectly normal in between the lock-ups ... My final lock-up consisted of a car taking off the back of my car ...and it happened in a split second ...or so it seem's ...when your just driving along and all of the sudden your car tries to come to a screaching halt out of the blue it is crazy ,but even crazier is that the person behind me had no clue at all ...I guess if the ABS did not come on there were no lights then and they don't know My car is going to try to stop dead in the middle of the highway!

Who could pay attention to anything through all this ...I don't know.

 

Question? Does the brakes apply to assist the VSA (wheel spin), and if so there could be brakes involved in this if the computer senses wheel spin. If the computer over reacted then it could be envolved with car making a sudden stop, as you had (that girl). Look, there something crazy going on, as I did experience when my acura down shifted at 50/60 mph. Has anyone requested or received an explation from Honda about what is going on when these units act up?

 

Very good question Aclura...... I have always wanted to know HOW tis can happen ..most of what I read is very technical and makes no sense to me . I have read that the 3rd gear clutch pack debree can clog filters and this is responsible for lock-up's ...but again ,...in between these lock-ups there is no problem at all ...Then with this new recall about the 2nd gear chipping ..I wondered if that was what happened to both my transmission's ...But if a gear chipped broke ,it would seem that it could not possibly drive normal in between lock-up's ...so 3rd gear cluth pack does seem more the cause ,but wish I could really understand all the technical reasoning behind this ..

 

The way mine tranny down shifted, my guess would be that the computer made it shift?? My trans fluid had just been changed, and the oil jet kit installed. It had about 10 miles stop and go, and then 40 miles on the interstate. It started its supershift after the first exit.