Auto Tranny Query - Comments, please

[Renegade]

Hi guys,

 

Posting for a friend who bought an early '04 (pre-facelift current generation) Camry who's facing this peculiar issue - when on a gradual slope, (say,

[Maded]

Auto gearboxes not supposed to be able move backwards on a slope... or at least it hasn't happened to me... My experience with autos is that is the slope is not too steep the car will actually move forward (not braking lah). But if the slope was steep, it'd stay put.

 

However with most older auto cars, when you put it in P and don't engage the handbrake, you'll find that it does have a tendancy to roll a few inches depending on the slope. But it does stop at a few inches.

 

If you mean that the car just rolls and rolls, you may have a problem with the tranny...

[Jhoo]

My guess:

 

The 1st case: sounds like a clutch slip on 1st gear. A premature wear & tear for a '04 car though.

The 2nd case: Electronic controller should compensate the fuel supply whenever aircon cuts in and out. For yr case, probably the aircon cuts out, engine load reduced but not the fuel supply, casing a lurch as if depressing the acelerator suddenly.

[Sapience]

that's strange, i thot on slopes with enough steepness, the car will roll backwards, because the forward motion not enough to overcome the downward pull. isn't this normal? experienced this with my current and last cars...

 

maybe you've not been on a steep enough slope yet... heh

[Maded]

erm... maybe lor...

 

My car stick shift... all the other auto trannys i drove were borrowed or rented....

[Kytl68]

In my previous two auto cars (Nissan K1 & Daewoo Leganza), on D mode it does not roll backwards unless it's very steep like in parkway parade car park entrance ... but stepping on the acceleration a little does the trick.

 

But my current Kia Optima auto, it does roll backwards in less steep slope ... I am guessing it's got to do with the design of the auto trans ... maybe it's gear ratio at 1st gear on lower rpm is not sufficient to hold the car on a slope. Now I have to use the hand brake on a steep slope.

Edited January 6, 2005 by Kytl68

[En0203]

not sure about camry. on my sunny in D, it'll roll backward if the slope is steep enough,

[Renegade]

Hi all,

 

Thanks for the tips - I'll forward him this link

 

The latest update I've got thus far is they're still maintaining the "it's lidat wan la" stand and refuse to do anything else....

[En0203]

they're still maintaining the "it's lidat wan la" stand

 

maybe it's really like that one le

checked with other camry driver before?

[Apollo]

depends largely on the ATF fluid, could be result of oil slip.

 

also depends on the contact between final drive and the drive shaft.

 

also depends on the gearing ratio of the final drive.

 

will car slip backwards if the gearing ratio is high... probably will.

[Maded]

you're probably right... but for stick shifts, it's clutch clutch!!!

[Kytl68]

They are talking about car rolling back at low speed ... so how to be in final drive ???? ... shoudl still be in 1st gear ... otherwise transmission really got problem

[Hattee]

Slipping or not at slope doesn't tell if the engine is good or not. Braking (incl handbrake) is essential at slope.

 

Slipping got to do with weight, gear ratio and idling torque. Heavier car is less prone but still slips at steeper slope. If lighter car doesn't slip only means greater iding torque requiring harder braking at stand-still - not exactly healthy for converter I think.

[Apollo]

BECOS it is auto, there is no specific gear to pinpoint the problem. but the weight of the car is acting down (due to gravity) but this is set back diagonally, so as long as the gear ratio is not able to overcome the wt * gravity, there is chance the car will roll. the final drive is the sun gear link directly to the drive shaft which is the only possible reason why the gears will turn. it is the 1st to b in contact with any turning directly.

[BMW320i]

Auto cars usually move off with gear 2.

 

The basement carpark at Great World City, when you exit, check out the slope... So far I am able to stay stationary without brakes but when near the end of the slope where its even steeper, even in gear 1, my car will still slip back.

[Clio]

can u explain what do u mean by D or P the car show tendency to slide backward?

on slope your torque convertor tend to slip and your car will slide backward...normal what.

in P your car will slide backward slightly before the wheel get locks...normal what.

lurch forward?

[Clio]

move off gear 2?

where you learn this from?

or which climate anti slip control u pressed?

its not the power of the car but the amount of load to slip your torque convertor.

if the torque convertor doens slip...you will stall your engine whenever you brake to a stop.

[Kytl68]

Gear 2 or Gear 1 means your gear will not change to higher gear as you move along ... but it still starts at 1st gear .... isn't that so ????