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A8 Clunk/Thud when putting into reverse or drive

27K views 53 replies 21 participants last post by  thefatcat1 
#1 ·
Is this common?
Almost every time i put the car into drive or reverse after leaving work, I get a thud or clunk once the gear engages and you can feel the car lurch forward.

Thanks
 
#4 ·
Would the 2016 still need that TSB?
Attached is the one that applies to 2016 vehicles.

SUBJECT: Flash: Transmission Shift And Drivability Enhancements

OVERVIEW: This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. MODELS: 2016 (LA) Dodge Challenger 2016 (LD) Dodge Charger 2016 (LX) Chrysler 300 NOTE: This bulletin applies to vehicles within the following markets/countries: NAFTA, LATAM, EMEA and APAC.

NOTE: This bulletin applies to the following vehicles built on or before August 05, 2016 (MDH 0805XX) equipped with a 6.4L engine (Sales Code ESG) and equipped with an 8HP70 automatic transmission (Sales Code DFK) or equipped with a 6.2L engine (Sales Code ESD) and equipped with an 8HP90 automatic transmission (Sales Code DFE).

SYMPTOM/CONDITION: A small number of customers may experience a less than desirable down shift during one or more of the following: • 3-2 coast down shift. • 2-1 coast down shift. • 6-5 coast down shift.
 

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#5 ·
I find that I have a clunk when I am just cruising with my foot on the gas and when I remove my foot from the gas petal and re apply there is a little clunk. Almost like there is a little play in the transmission/driveshaft/rear end and its catching up when a apply the gas petal. I have a 2015 , don't know if the TSB would apply.
 
#7 ·
The TSB fix may correct the issue with your "thud/clunk" by accident, but it sounds to me like the TSB is about correcting rough downshifts in the A8. Your issue sounds more like either excessive play in the ring & pinion or a sloppy U-Joint (i.e. excessive play in the driveline) since you didn't complain of downshifting issues but rather a thud/clunk when you put the car in gear. I suspect your problem is unrelated to the problem targeted by the TSB

Do you have any downshifting issues during 6-5, 3-2, or 2-1 coasting downshifts? If not, then I suspect your issue is more of a mechanical than an electronic issue as stated above. Another relevant question is, have you altered the differential in this car? Maybe 3.09 gearing?

In the event of excessive driveline play, the problem would be more pronounced when the vehicle is stopped as in shifting into drive or reverse, and while still noticeable while moving, the problem would be lessened while the vehicle is in motion.
 
#8 ·
Interesting timing of this post/thread. I was backing out the other day and just moments after, the rear rend made a loud groan or rubbing sound. I immediately hit the brake, as my daughter and I both thought we backed into or over something. Nothing was there and it has not done it prior or since. It was very cold that morning....not sure if that had anything to do with it.
I do have the rear end groaning at low speed and acute turns that many people have noticed. Have not taken the vehicle in for inspection on that as of yet.
 
#27 ·
The clunk is pretty violent lurching the car forward no matter how hard i put my foot on the brake, its almost as if its taking away all the driveline slack.

What really bothers me is when coasting to a stop or braking to a stop with the transmission in street mode, I can feel the rough downshifts everytime im driving casual.

I just had the TCM/PCM flashed with the latest software, but no change in the rough downshifts so far, or the large lurch forward when putting it into "D".
 
#31 ·
The other thing to keep in mind is if you are on a grade and not using the parking brake. There will be increased stress on the parking pawl if your car is tilted up / down when moving from P to R/D after being parked / stopped.

If you're parking on a grade, apply the parking brake (with regular brakes applied) before you release the regular brakes after shifting into park, and release the parking brake (with regular brakes applied) before you release the regular brakes when shifting out of park into R or D to remove the weight of the car from resting entirely on the parking pawl.
 
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#32 ·
Hey folks... I noticed this sound today on my 2017 A8 Charger Hellcat.

If I just sit in my driveway and engage D or R, I get a clunk. I don’t even actually have to move... just makes the clunk as I go from D to R or vice versa. Car drives fine otherwise, but this doesn’t sound right at all.

I’ve got 5700 miles of town and highway driving and 3 trips to the track. I also have the DSS Aluminum driveshaft and stock rear end.

Has anyone confirmed for sure what resolves this? An active TSB?
 
#34 ·
Thanks... need to find the right place to take it.

I'm very weird about who I let look at anything to do with engine or transmission.
 
#35 ·
Apparently there is a TSB for this, but I'm not sure it it's active for 2017 cars.

I also have the Aluminum DSS. It was recently installed. Need to make sure all is good with that.

Worst case I could have problem with rear end gears or transmission.
 
#39 ·
Man this is what I am hoping it is! I just had the new one-piece DSS installed and ran an entire weekend of one-mile races last weekend, and the clunknshowed up the day after it ended. Racing was all soft launch on street tires on airport runway (unprepped surface). Only thing the newly installed DS saw was lots of speed, start and stop. So I think Force-caused damage to anything should be unlikely based on what I was doing, and I am really hoping it is just new part needing to be re-torqued.
 
#38 ·
Mine only happens once when the transmission and driveshaft change torque direction when engaging R or D, and happens at a dead stop just same as when moving. It’s all about the change in torque direction occurring through the main DS. So this tells me it has nothing to do with the wheel DS, but more likely the transmission, DS, or rear end.

If your clunk occurs when moving while turning one direction or another, that gives different clues and may tell you one of your half shafts has issue.
 
#40 ·
Just doing my service to the community and reporting back and confirm root-cause... was indeed loose driveshaft bolts.

Pause and “clunk” when engaging into drive or reverse was just loose DS bolts... was the large ones that torque to 70 lbs. they seem to have backed out some since installation. If it happens again I’m going to go nuts on them with thread-lock.

This happened about 1 month after DSS Aluminum install. One trip to drag strip and one weekend at Texas Miles is what loosened ‘em up.
 
#42 ·
Good question... don’t know... gonna look for the manual.
 
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