atraudes

I noticed my car doesn't creep forward when it's in drive and my foot is off the brake. In pretty much every other car I've had it moves forward to some degree, but not this one. Is that normal/expected?

C300CA

Not sure if it's abnormal or not but my car moves forward on a leveled street.

ChazThePhoenix

have you engaged the brake hold?

when you are a light, press the brakes, then press firmer for hill hold. you can then sit at a light all day without your foot on the brakes..

superangrypenguin

To answer the OP, no, it's not normal.

atraudes

Well hell, that's not what I was hoping for Any ideas as to the cause?

I changed the transmission fluid today with no change. I've noticed that it does move forward and backwards when the engine is cold, so for the first minute or two.

I'm pretty sure I'm not engaging the hill hold feature. I just push the brake to a certain position to stop, then hold it right there until I'm ready to go. I'll pay attention to whether the car drifts when I let go of the brake on a hill to find out.

M~Factor

mine does not creep forward as well. especially not on reverse.

Moto_Guzzi

Well I would think idle revs when in drive or reverse matters as well as the ability to hold up to it without throttle, as well as torgue converter oil thickness temp.

I think you should compare revs when this happens, lets see if your car does not idle too low, or weak power at idle, my guess.

atraudes

That's a good call. I'll keep an eye on where it's idling.

atraudes

Also, thanks for all the feedback and experiences, everyone.

atraudes

I did some experimenting yesterday and found a few things. Once warmed up, it idles at just above the halfway mark between 0 and 1, so probably 600 rpm. Second, and this may be because of the flush, it does creep forward. It's not much, but it does. However, it only does if it's on perfectly level ground. Once it's on any sort of incline (like the driveway immediately outside the garage, it seems) it's enough of a hill that it holds in place, and will stay in place indefinitely.

I also messed around with the hill hold feature and the 3-second grace period it gives you on hills. When you push the brake down farther at a light, a hold icon shows in the display. When I'm stopped at a significant hill and just let off the brake, the car stays in place for about 3 seconds before letting go and coasting backwards.

I think I only noticed when it didn't move forward, and must not have noticed when it did since it was so little. The fact that even a small incline stops it from moving was what messed me up. I'm good with calling this case closed for now, unless anyone has any followup questions or experiments.

I am curious if M~Factor would have the same findings if you tried the same things.

Moto_Guzzi

I tried compared some on both my automatic vehicles:
Merc:I had to reverse out of garage, left turn, then put in Drive move forward, reverse again if turn was not sharp enough out of garage, then move forward ,right turn, left turn, out to the gate. Nowhere here do I have to tough the petrol, just brakes, fairly level, it just creeps along.
Rev's seem to be between 650 & 750. At a hill, it does not hold after brakes released.
Izuzu(3L Diesel): Same route/moves, it creeps stronger, had to watch the brakes. Also does not hold on same hill. The revs about 800-850.

Note: The Merc with engine off, I can push forward/backward in neutral easily on garage floor, the Izuzu I have to apply real heavy force to do it. The only reason I mention this, is because the Merc is the 1st car I owned that pushed that easy, I immediately noticed that after receiving the car.

Note: When , after what did your car start doing this-?
I assume if your gearbox/torgue converter is underfilled, you will have a message-?
I would be interested to know if your engine has weaker "torgue" at idle that it should have , for whatever reason, also how easily do your car push on
garage floor by hand in neutral-? I also assume if anything brakewise was dragging, you would know about it by now.
Let us know what the reason was.

atraudes

I think it's done it ever since we bought it (a few months ago). If it was underfilled, it wasn't by much. When I did the fluid exchange I got about 9 liters out which seems to be par for the course. No change in behavior after fluid change.

I can check out how much force it takes to push it in neutral. I'm guessing the test here is to see whether there are any drivetrain restrictions beyond the transmission?

The front passenger brake had a frozen slide pin when we got it, but that was taken care of under warranty. There hasn't been an abnormal amount of brake dust built up on the wheel so it's safe to assume it's been resolved.

All good questions! Unfortunately there don't seem to be many answers, and the replies above are conflicting