Actually, two questions in one thread.

First: I notice a clunk when I accelerate after letting off the gas if my car is going between 20-35 MPH. No sounds when accelerating from slower than 20 or higher than 35ish. Is this normal on this car? Did some googling and found a whole range of answers, but nothing definitive.

Second: When I start my car in the morning, I notice a slight lag between shifting to drive and when my car begins to move forward. This only happens the very first time I shift into drive (sometimes I have to shift into reverse then back to make it out of the driveway, no lag the second time). Transmission fluid level seems fine on dipstick. Should I be worried about this?

Thanks!

 

The clunk could be a million things. My 2003 had a clunk that was driving me crazy which eventually turned out to be a loose counterweight in the trunk lid.

My car has also has a slight lag, maybe a second or so, before anything happens on a shift from P to D or R. I don't worry about it.

 

Thanks for the reply! Yeah I figured there's probably a ton of possible causes for the clunk. Thought maybe someone's experienced the same maybe though, but didn't really expect much

Anyways, guess I'll continue driving it. I've experienced the clunk basically since i got it used, so I guess it's probably not a huge deal.


Another question if you don't mind: I noticed that when I come to a stop, my engine RPM dips significantly (usually to 1/3x1000), before returning to 2/3x1000 a second later. Is this normal?

Thanks!!

 

I assume this is a CVT? If you haven't replaced the fluid in the last 12000 miles, do it. If you haven't flushed it, change it 3 times with a week in between to purge out all the old fluid. Continue to replace CVT fluid every other oil change (12-15K).

idle rpm drop is not normal.

 

I tested this repeatedly on the drive to work today. 2003 HCH I. To do so the economy mode had to be disabled, because of course normally when the car stops the motor turns all the way off. If you are seeing this all the time a better question might be: why is the car not doing an autostop?

On a typical stop, that is one where I slow down gradually, either gliding or with slight brake pressure to trigger IMA recharge the bounce you describe does not happen. The RPM drops to about 2/3 x 1000 at stop with no bouncing.

However, when the car stops relatively suddenly it will do the RPM bounce. For instance, back up two car lengths, stop, move forward the same distance, and stop quickly, as in reparking in a parking lot space, and it will do what you described. None of the warning lights come on when this happens. Sudden stops are not something I do very much, and when it does happen in normal driving I'm usually looking at whatever it is that just placed itself in front of the car, and not at the tachometer!

There wasn't enough testing to tell if the "bouncing RPM" happens only on stops from relatively low speeds, or if it does it on a sudden stop from 30 MPH or more.

My transmission was rebuilt several years ago and has had regular CVT changes ever since. (It is only driven ~6K miles a year, virtually all of it in suburban driving.) I don't have any reason to think that the way it is behaving now is abnormal.

 

Thanks for the reply. Planning to get that done this weekend along with oil change.

Wow, thanks for testing that out!

You're right, I only notice the RPM drop when I stop suddenly. I only noticed this behavior a couple weeks ago by chance, and I found that, like you, coming to a stop slowly doesn't cause the bounce.

As for autostop, I wasn't sure whether I should have that enabled. I've heard that it's not great for the car, not sure what your thoughts are about that. In the past when I had autostop enabled and I'm coming to a stop just as the light turns green/traffic begins to move, I would hear a clunking sound when I press on the acc pedal (kinda like the clunk I hear when accelerating from 20-35).

 

Also, another question: How low should the fluid go when the car is in drive? I checked the level yesterday when my car was in D and saw that the level was right around the HOT lower mark. Does this mean the fluid level is low?

When I check it after turning off the car the level is higher. I didn't think of checking it in gear until I read about it online.

 

Autostop is one of the main reasons for owning a hybrid. No wasting gas while sitting immobile at lights. It doesn't hurt the car. In those situations where the car doesn't think it will be able to restart from autostop with the electric motor, for instance, too little charge in the IMA, it just won't stop the motor.

I have on occasion observed what you mean about stepping on the gas at almost exactly the same time as the autostop kicks in. That seems to confuse the logic in the transmission or somewhere and there can be a bit of a lurch, although I don't recall any associated clunk. It may be related to the "car takes a second to start moving after shifting into drive" phenomenon. The few times I have experienced this the car was moving at maybe 3 mph, had just shut off the motor and was about to stop. Now that I think about it, when I'm in that situation now I take my foot off the brake, wait a second or two, and then press the accelerator, which doesn't trigger the lurch. Probably I trained myself to drive like that after experiencing the lurch a few times shortly after I bought the car. Remember the CVT doesn't have a torque converter, it has internal clutches, so it isn't a great idea to demand a huge amount of torque from it at the exact same time the clutches are changing state. Always best to let a clutch, any clutch, fully engage before requiring it to transmit a lot of power.

I can't answer the fluid level question.

 

I see. I've started adopting that behavior as well (especially since I not only feel a lurch but also hear a clunk). I guess clunk is probably because the car's old and stuff's worn down. Hope it lasts for a while longer.

I didn't know about the CVT not using a torque converter. Will keep that in mind.

Thanks for the useful information!

 

As posted above could be the clutch, but also check the torque on the sub frame mounting bolts. Had similar issue turned out 3 loose bolts and one missing completely. But yes if i pop throttle quickly my tranny gets pretty unhappy.