knock before gear change

[pitbull30]

I have a 2001 Corolla. Automatic Transmission. 75k

Recently I noticed it has a knock for a few seconds right before the gear changes on all the gears. I had the plugs changed a few weeks ago to NGK Platinum. So I dont think its the plugs. The weather just recently changed form warm to cold, and this is around the time I started noticing it. My questions are:

Is this a timing issue? If so is it fairly easy to set?

Spark Gap perhaps? what is the correct Gap? Maybe the Mechanic gapped them wrong?

Timing Chain?

Cold weather?

Thanks

[Bitter]

the word knock is pretty generic. does it only do it when the gear is about to change? if you put the car into a lower gear and drive it so it wont shift will it do it? in park will it do it?

[DoubleEdgedWomb]

If you mean a pinging problem, I know exactly what you're talking about. Unfortunately, that's more or less a design flaw with these engines.

[ghost_ryder35]

Originally Posted by pitbull30

I have a 2001 Corolla. Automatic Transmission. 75k

Recently I noticed it has a knock for a few seconds right before the gear changes on all the gears. I had the plugs changed a few weeks ago to NGK Platinum. So I dont think its the plugs. The weather just recently changed form warm to cold, and this is around the time I started noticing it. My questions are:

Is this a timing issue? If so is it fairly easy to set?

Spark Gap perhaps? what is the correct Gap? Maybe the Mechanic gapped them wrong?

Timing Chain?

Cold weather?

Thanks

plugs are pre gapped - and you should of saved the money and changed them your self
timing chain - probally not, only thing related to that would be the tensioner but that usualy doesnt go and if it does its around 150-175k and wouldnt make any noise changes at shift points
cold weather - hell it affects everyone and everything, very well could be yor problem, but what is the cold weather doing to your car to make these weird noises, are they very loud? Maybe taking it to the dealer to get the free 30point inspection would be a good idea right now so they can tell you what is wrong if anything is

[pitbull30]

Yes it only does it right before gear change. I tested it in park and I cant hear it. I also put it in low gear and drove it down the street and I couldnt hear anything.

It sounds like a marble in a tin can right before gear change.

I do think the weather does affect it alittle because today is a semi warm day. I drove it alittle earlier though and heard the noise a few times. I can mainly hear the difference on the freeway or pulling hills. In order to hear it I have to listen with the windows up and radio off.

Am i crazy or is this a common thing?

[90 GP]

Sounds like the engine is pinging from your description. Try a different brand and/or grade of gasoline. If that doesn't help may need the timing checked and possibly adjusted. You probably have a build up of carbon in the engine which is aggravating the situation.

[Bitter]

yea, sounds like some mild detonation. are you hard on the pedal when this happens or just gently driving it? you might try some higher octane fuel and then drive it hard for a little while. the higher temps of hard driving can burn off some deposits, or do nothing.

[jon_570]

Originally Posted by pitbull30

Yes it only does it right before gear change. I tested it in park and I cant hear it. I also put it in low gear and drove it down the street and I couldnt hear anything.

It sounds like a marble in a tin can right before gear change.

I do think the weather does affect it alittle because today is a semi warm day. I drove it alittle earlier though and heard the noise a few times. I can mainly hear the difference on the freeway or pulling hills. In order to hear it I have to listen with the windows up and radio off.

Am i crazy or is this a common thing?

my friends truck did this awhile ago also an automatic and it would make a loud click before each gear change...then it started clicking during idling..in park and drive but wouldnt in neutral..found out he blew his torque converter and it was pretty much blowing itself to pieces..not saying it is your problem but just stating from experience