The Small Questions Thread

[robertwsimpson]

I love this thread... I have a whole list of little questions, not sure if they are normal behavior or something that should be looked at.

How much rotational free-play (slack) should there be in the driveline? I fear that mine may be too loose. When applying torque from a "coast" or removing torque to a "coast" I hear a clunk from down there.

Some examples:
Shifting from Neutral (clutch engaged) to First without allowing sufficient time for the input and counter shaft to spin down to a stop.

When disengaging the clutch a split second before the throttle has evened up with the vehicle speed.

Normal? Or sloppy driveline?

Mine does this too. I believe you're hearing the synchros doing their job.

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[oneheadlite]

Who left the cap off of the toothpaste tube???????????

 

[kh1818]

Hmmm... You need to look at this thread...

http://www.mustang6g.com/forums/showthread.php?t=15990

While that certainly may be it, I think that the mirrors (side and rearview) are not mounted using a strong mount. For example, I had that vibration issue, and had my rear diff replaced, which fixed the issue. However, if you play music at a moderate, comfortable volume, the bass will cause the mirrors to vibrate, something I have never experienced in any other car at any volume. Also keep in mind I have the base level stereo, which has barely any power especially for bass frequencies. So the issue may just lie in the rear view mirror mount being too flexible and allowing vibration when it should be steadfast.

 

[Grimmer]

Also anyone find this car extremely tricky to park?

I bugged me for a long time that I was always just a little bit crooked. I wondered if the guide lines on the back-up camera were a little out of whack (I still think that mine are a little off).

However, I have found that the issue messing up my ability to park correctly was that the rear tires are wider than the front. If the two tires on one side are straight then the two on the other side are way off. So just shoot for the middle...

I always try to park at the end of a row where I can snug up against the curb and have more buffer space for opening doors. However, I have the California Special rims and don't want any curb scuffs so I've been extra particular about parking.

When in doubt, back out and start over...

Never park next to grass or under a tree. If I can't find the end of row with no grass or trees, then I'll go for some open space. If all else fails, I'll look for two cars that both have their passenger doors facing the space I want to use. Less likely that they have passengers with them (especially at work) so less change of a door ding.

 

[Grimmer]

Mine does this too. I believe you're hearing the synchros doing their job.

I thought about the syncros since I get some clunk every time they have to make more than just a minimal synchronization...

However, I also get a clunk from under and behind when disengaging the clutch before the torque has equalized (letting off the throttle to shift, but pushing the clutch pedal just a split second too soon). Gear has not been changed yet.

I also get a clunk from under and behind when re-engaging the clutch (like in heavy traffic) without having changed gears at all. Just resuming power from having been coasting with the clutch disengaged (pedal down).

I was also surprised with how much "whiplash" I get when feathering on and off the throttle with this car. I.e. slow speed maneuvers (traffic / parking lot) when switching from mild engine braking to barely accelerating or vice versa.

Seemed to me that a sloppy driveline and/or too much lash in the rear differential could cause such behavior. However since I've never driven anyone else's car, I don't know if this much "slop" is just normal for a large/heavy and powerful car (i.e. normal/necessary slop but is just more noticeable with higher horsepower vs. weight than I'm used to with previous smaller cars).

I have the 3.55 gears and can't help but speculate whether or not it was built and shimmed properly as a 3.55, or if they actually swapped out a stock one on the line (still wonder about the shimming).

On the flip side, if there aren't any long term detrimental effects, I probably wouldn't do anything about it. My car doesn't suffer from the highway speed "vibration" that so many are plagued with and I wouldn't want to risk the dealer wrenching on it.

I suppose I'll have to look into buying that shop service manual a little sooner than I had originally planned...

 

[Grimmer]

Has anyone else noticed if their manual GT/PP2 idles down a few hundred rpm when sitting at a stop light with your foot on the brake?

As soon as I let go of the brake pedal the rpm hops up a few hundred... Hold the brake again and within about a second it idles down.

 

[GTP]

Has anyone else noticed if their manual GT/PP2 idles down a few hundred rpm when sitting at a stop light with your foot on the brake?

As soon as I let go of the brake pedal the rpm hops up a few hundred... Hold the brake again and within about a second it idles down.

Might be that Hill Assist feature?

 

[GTP]

I thought about the syncros since I get some clunk every time they have to make more than just a minimal synchronization...

However, I also get a clunk from under and behind when disengaging the clutch before the torque has equalized (letting off the throttle to shift, but pushing the clutch pedal just a split second too soon). Gear has not been changed yet.

I also get a clunk from under and behind when re-engaging the clutch (like in heavy traffic) without having changed gears at all. Just resuming power from having been coasting with the clutch disengaged (pedal down).

I was also surprised with how much "whiplash" I get when feathering on and off the throttle with this car. I.e. slow speed maneuvers (traffic / parking lot) when switching from mild engine braking to barely accelerating or vice versa.

Seemed to me that a sloppy driveline and/or too much lash in the rear differential could cause such behavior. However since I've never driven anyone else's car, I don't know if this much "slop" is just normal for a large/heavy and powerful car (i.e. normal/necessary slop but is just more noticeable with higher horsepower vs. weight than I'm used to with previous smaller cars).

I have the 3.55 gears and can't help but speculate whether or not it was built and shimmed properly as a 3.55, or if they actually swapped out a stock one on the line (still wonder about the shimming).

On the flip side, if there aren't any long term detrimental effects, I probably wouldn't do anything about it. My car doesn't suffer from the highway speed "vibration" that so many are plagued with and I wouldn't want to risk the dealer wrenching on it.

I suppose I'll have to look into buying that shop service manual a little sooner than I had originally planned...

I think if I were in your situation, I would check around for a dealer that has a Mustang mechanic with a good rep, and that has built a diff before. Then schedule a morning appointment with him so that he is fresh when doing the precise lash adjustment.

The 5 year warranty comes in handy for this job.

Fortunately for me, the closest dealer is 2 miles away and has such a guy.

 

[Grimmer]

Might be that Hill Assist feature?

I do use the hill assist feature, very convenient, but I understood that to only involve holding the brakes and only when a sufficient (and appropriate direction) incline is detected.

The idle change happens for me even when the hill assist is not holding the brakes for me. I'll have to test that one out. I assumed that the rpm change was using the brake lights as a trigger (which are also held on by the hill assist). So if the hill assist is holding the brakes and brake lights, then the car shouldn't idle up (thinking my foot is still on the brake). Although, it could be directly related to the brake pedal switch regardless of the brake light status.

Ultimately, it is probably not possible to find out which system or feature is doing it, or if it can be enabled/disabled. It was just something I noticed...

My first thought was that it is done to prepare the engine for the pending clutch transition, but a few hundred rpm wouldn't make that much difference.

My second thought was that the idle down was done to get the engine sound down into that iconic low rumble when it has nothing better to do.

My third thought was some type of misplaced fuel economy / emissions reduction scheme...

 

[Grimmer]

An unrelated observation...

Most MT guys are familiar with doing a "lazy shift" and having the engine rpm drop and hold for a few seconds at the correct rpm for the next higher gear. However, I have noticed that if you tap the brakes it will skip that rpm hold and drop straight to idle...

 

[Grimmer]

I think if I were in your situation, I would check around for a dealer that has a Mustang mechanic with a good rep, and that has built a diff before. Then schedule a morning appointment with him so that he is fresh when doing the precise lash adjustment.

The 5 year warranty comes in handy for this job.

Fortunately for me, the closest dealer is 2 miles away and has such a guy.

I would love to find a decent mustang mechanic at the dealer. But so far, my experiences with the dealer shops hasn't been very good.

There are quite a few dealerships within striking distance. I have tried several of them, but not all of them.

If anyone knows who is good in Utah, then I'll give them a shot. So far I've found that I am way more meticulous and have greater concern for doing it, not only the right way, but the best way possible than any paid by the hour shop I've come across to date.

I'm always on the look out for good intel about local shops. Perhaps that is a good idea for a sticky thread in each of the respective regional forums. In the meantime, I'll either have to find the differential lash and driveline slop specs on the internet or pony up for a service manual.

For now, I've just been enjoying driving a truly fantastic car but those little questions still stick in the back of my mind...

 

[Sig556]

I thought about the syncros since I get some clunk every time they have to make more than just a minimal synchronization...


I also get a clunk from under and behind when re-engaging the clutch (like in heavy traffic) without having changed gears at all. Just resuming power from having been coasting with the clutch disengaged (pedal down).

You may want to check your U-Joints for slop. If there is any looseness you will hear a clunk anytime your car in placed into gear more so on a automatic.

 

[goldengooner]

Maybe it depends on the model year. My 2016 401a does not include the reverse sensing. That was a separate option available with or without the 401a. On the 2016 you will know whether or not you have the reverse sensing option because the upper right corner of the reverse camera image will have a top view overlay of your car with green, yellow, and red fan areas behind it. As those areas light up while backing you will hear distinctive beeps warning you of the remaining distance.

I have a 2016 CS and I have them, is it not part of the BLIS and Cross Traffic Warning system ?

 

[goldengooner]

While that certainly may be it, I think that the mirrors (side and rearview) are not mounted using a strong mount. For example, I had that vibration issue, and had my rear diff replaced, which fixed the issue. However, if you play music at a moderate, comfortable volume, the bass will cause the mirrors to vibrate, something I have never experienced in any other car at any volume. Also keep in mind I have the base level stereo, which has barely any power especially for bass frequencies. So the issue may just lie in the rear view mirror mount being too flexible and allowing vibration when it should be steadfast.

That's a new one on me :eyebulge:

 

[goldengooner]

Here's a new small question...

Does anyone else using the automatic memory mirror and seat adjustment feature (i.e. whenever my car is unlocked with my FOB it automatically restores "driver 1" settings) have this problem:?

Every once in awhile the side mirror (either one) gets confused and moves all the way up, thumps against the stop a few times and then moves back into position.

it happens on mine sometimes, when i change the settings to button 2 which lowers the mirrors to park easier. other then that, have had no issues

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