Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (Full Version)

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Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed...

  

SDRaymond -> Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 9:29:46 AM)

This is my first post, so be gentle [:)]...  I have a 2004 Chrysler Sebring Coupe, (I know, I know [;)]) which was designed and built by Mitsubishi for Chrysler.  Anyway, it has the Mitsu 6G72 3.0L engine and Mitsu F4A51 Transmission.  I'm experiencing a shudder when climbing hills, even if moderate, and when accelerating, but this only happens at highway speeds and while accelerating to highway speed.  At lower speeds and from a standing start, acceleration is completely normal with no shudder whatsoever

Here's what's been done so far:
  • New plugs - NGK Iridium
  • Had the Chrysler garage check for engine and transmission codes (intermittent MAF code only)
  • Rotated tires
  • Replaced transmission fluid - Mitsu SPIII
  • Cleaned throttle body
  • Used injector cleaner - Techron
  • New air filter

One "oddity" that I did notice while changing the plugs was dark "stains" between the intake ports on the gasket, intake plenum, and intake manifold.  I don't know if this indicates leakage between the port or not?  I did clean the surfaces of all three items thoroughly before reassembly.

Any ideas?

Thanks in advance!

Scott

  
TheEngineer -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 12:10:17 PM)

tires need to be balanced maybe. Does it do it when your on the highway at a constant speed or only when accelerating?

SDRaymond -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 12:20:38 PM)

Only when accelerating or climbing a hill...

Manybrews -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 6:03:47 PM)

its a shuddering torque converter clutch.
you need to have the transaxle FLUSHED COMPLETELY, using ONLY mitsu trans fluid.  Nothing else should be used.


SDRaymond -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 8:18:11 PM)

I've already flushed the transmission with 13 qts of Mitsubishi SPIII ATF, no change...  However, I was looking things over this evening and discovered that the lower motor mount, which transfers the torque from the engine to the frame, has a huge rip in it.  Could this be the cause of the problem?

Thanks!

SDRaymond -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/20/2006 10:23:27 PM)

BTW, I also had the wheels balanced today, no change...

Does the Transaxle have to be power flushed or is a simple fluid replacement (following recommended procedures of course) adequate?


Manybrews -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/21/2006 4:15:33 PM)

power flushed.

it really sounds like a torque converter shudder.   Does this condition happen immeadiately after a cold start, or does it take awhile?  I ask because the torque converter clutch doesnt engage until the trans reaches about 140 degrees, so the shuddering issue may not be present until 5-10 minutes into your drive cycle.

how many miles are on your car?  
Also, if it is infact torque converter shudder, a total fluid change usually takes care of it.  But in a few percent of the situations a new converter MAY be needed (although I have yet to see that actually happen).
heres a small sample of the TSB about it.
[img]http://home.mn.rr.com/hartsstuff/T%20C%20shudder.JPG[/img]


silvercoupe97 -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/21/2006 7:42:36 PM)

^^ I would say that, that about covers it, lol.    

SDRaymond -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/21/2006 11:25:29 PM)

Manybrews, thanks for the information!!!  The problem occurs only when the transaxle warms up.  The car has ~128,000 (nearly all highway, 70mph+) miles on it.  I did a complete fluid change earlier this week (with Mitsubishi SPIII) with no change to the problem.

As I stated earlier, this is essentially a Mitsubishi with a Chrysler logo on it.  I had the fluid replaced by the dealership at 50,000 and 100,000 miles.  I'm starting to think that they may have installed Chrysler ATF +4 instead the required SPIII.  Bottom line, I'm going to take it to a Mitsubishi dealership next week to have the Transaxle completely flushed and fresh SPIII installed (darn, I hate to dump $85 worth ATF I just installed).  How much does this typically cost?

Thanks again.

Manybrews -> RE: Car Shudders While Accelerating or Climbing Hills - Only at Highway Speed... (12/22/2006 8:07:06 PM)

quote:

ORIGINAL: SDRaymond

Manybrews, thanks for the information!!!  The problem occurs only when the transaxle warms up.  The car has ~128,000 (nearly all highway, 70mph+) miles on it.  I did a complete fluid change earlier this week (with Mitsubishi SPIII) with no change to the problem.

As I stated earlier, this is essentially a Mitsubishi with a Chrysler logo on it.  I had the fluid replaced by the dealership at 50,000 and 100,000 miles.  I'm starting to think that they may have installed Chrysler ATF +4 instead the required SPIII.  Bottom line, I'm going to take it to a Mitsubishi dealership next week to have the Transaxle completely flushed and fresh SPIII installed (darn, I hate to dump $85 worth ATF I just installed).  How much does this typically cost?

Thanks again.

probably around 200 bucks.

I realize its a chrysler badged mitsu;  Ive worked for mitsu for 15 years.

the milage on it almost assures it to be torque converter shudder.

  

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