Sometimes when you start up my car, within a split second of the engine firing up you get a clank and can feel the car lurch. This is with the shifter in Park. It seems to be more pronounced if the car is parked on an incline to where the front is higher than the rear by any degree. It can be on cold start or hot start. It is my understanding that this has to do with the torque converter in the 4T45E automatic transmission (okay, technically its called a transaxle since its front wheel drive) staying full of fluid after shut down or something (?...)

I would be inclined to think it related to fluid level, but its lost no fluid to my knowledge and the procedure for checking fluid level on the 4T45E is a pain in the neck (involves lifting the car but kept level, trans at a certain temp, trans in park and engine idling remove a check bolt-- if no fluid comes out, add fluid sparingly until it begins to dribble some out the check bolt hole... off the top of my head that is the procedure)

I was wondering if anyone knows if there is a TSB out for this condition? Its pretty much done it since new. 10,000 miles on the clock as of this weekend.

 

You might want to have your TCC checked out. The torque converter stays full of fluid no matter if the vehicle is on or off. However, the clutch inside the torque converter may not be unlocking all the way or improperly trying to lock up in park.

 

I remember doing searches for this problem back when I was having the clank when shifting into reverse (bad hub) and found references going back to the late 80s about this with various GM transmissions & transaxles.

 

I was walking up to mine today and hit the fob. Watched it as it started up then lurched and shut down. Guess I'll have to get it looked at too.

 

Was it parked on any degree of incline at the time? Being on an incline seems to aggravate it, on mine.

 

Here's one:

#08-07-30-026: Information on Slight Vehicle Movement in Park at Start Up After Cold Soak - (May 22, 2008)


Subject: Information on Slight Vehicle Movement In Park At Start Up After Cold Soak


Models: 2009 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)

2009 and Prior HUMMER H2, H3

2009 and Prior Saab 9-7X

with Automatic Transmission




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Some vehicles may rock or move slightly forward or rearward while in park at start up after cold soak. This condition may be accompanied by a clunk noise. This is a slight movement that is more often seen visually, rather than felt, when viewed from the outside and using the auto-start feature, if equipped.

This slight movement is due to the residual transmission fluid in the clutch packs that creates a partial apply on start up. This movement is stopped by the parking pawl and/or transmission fluid exhausting completely from the clutch packs.

This slight movement has no adverse affects on the transmission and no repair should be attempted. This condition is normal. This can be verified by comparing with another identically built vehicle under the same cold conditions.

To prevent this condition from occurring, the parking brake should be utilized as per the Owner's Manual recommendations anytime the vehicle is parked.

 

Sounds like when you drop a motorcycle into first it will sometimes lurch forward a bit when you first start it up...


Not to hijack but BR peaked my interest when he mentioned a cluck putting it in reverse......I changed my oil the other day and when I was finished and bringing it down off the ramps it made a very loud clunk when putting in in reverse. Lately the tranny has been making noises when putting it into drive, R etc...not like it was when on the ramps but enough to get my attention....I never noticed it before when the car had less miles on it (almost 35K now)

Not horribly loud but sometimes louder than I think it should be...do you guys notice a clink or sounds of the tranny when putting into D or R..is this normal or should it be pretty silent?



Goose

 

Goose this might be related to your problem:


2007 Chevrolet HHR | HHR (VIN A) Service Manual | Document ID: 2149741
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#99-04-20-002E: Information on Driveline Clunk Noise When Shifting Between PARK and DRIVE, PARK and REVERSE or DRIVE and REVERSE - (Jun 6, 2008)


Subject: Information on Driveline Clunk Noise When Shifting Between PARK and DRIVE, PARK and REVERSE or DRIVE and REVERSE


Models: 2009 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)

2009 and Prior HUMMER H2, H3

2009 and Prior Saab 9-7X




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This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 99-04-20-002D (Section 04 -- Driveline/Axle).


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Important: The condition described in this bulletin should not be confused with the following previous bulletins:

• Info - Discontinue Flushing and Replacing Transfer Case Fluid Due to Bump/Clunk Concern (Corporate Bulletin Number 99-04-21-004A or newer).

• Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) (Corporate Bulletin Number 01-04-17-004B or newer).


Some owners of vehicles equipped with automatic transmissions may comment that the vehicle exhibits a clunk noise when shifting between Park and Drive, Park and Reverse, or Drive and Reverse. Similarly, owners of vehicles equipped with automatic or manual transmissions may comment that the vehicle exhibits a clunk noise while driving when the accelerator is quickly depressed and then released.

Whenever there are two or more gears interacting with one another, there must be a certain amount of clearance between those gears in order for the gears to operate properly. This clearance or freeplay (also known as lash) can translate into a clunk noise whenever the gear is loaded and unloaded quickly, or whenever the direction of rotation is reversed. The more gears you have in a system, the more freeplay the total system will have.

The clunk noise that owners sometimes hear may be the result of a buildup of freeplay (lash) between the components in the driveline.

For example, the potential for a driveline clunk would be greater in a 4-wheel drive or all-wheel drive vehicle than a 2-wheel drive vehicle. This is because in addition to the freeplay from the rear axle gears, the universal joints, and the transmission (common to both vehicles), the 4-wheel drive transfer case gears (and their associated clearances) add additional freeplay to the driveline.

In service, dealers are discouraged from attempting to repair driveline clunk conditions for the following reasons:

• Comments of driveline clunk are almost never the result of one individual component with excessive lash, but rather the result of the added affect of freeplay (or lash) present in all of the driveline components.

Because all of the components in the driveline have a certain amount of lash by design, changing driveline components may not result in a satisfactory lash reduction.

• While some owners may find the clunk noise objectionable, this will not adversely affect durability or performance.

• For additional diagnostic information, refer to the appropriate Service Information.

 

Thanks CM...I guess this sort of adds a little fuel to the fire on the American Made quality debate thread....lol I love the part "makes an objectionable noise" and then pretty much saying sorry...that's the way it is lol

Can't remember any other car I have owned making this noise with so few miles on the tranny

Not a huge deal but still something


Goose

 

Yeah, actually it was... I can buy the fact that it doesn't do any damage to the trans but it apparently is strong enough to stop the engine when using the remote start (hasn't stopped the engine when starting with the key) and preventing you from using the remote start again to restart the engine. You need to start with the key to reset the remote. Its just another one of those little annoying things - like gnats.