Transmission

Tiny
052361
  • MEMBER
  • 1988 DODGE LANCER
  • 2.5L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 200,000 MILES
When I start the car the ideals is just fine. I put it in reverse and there is no problem, but when I put it in drive, there is a loud and hard clunk. When driving there is a lot of vibration and the car jerks and feels like it is cutting out but only in the forward gears.
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Friday, June 24th, 2016 AT 5:44 AM

9 Replies

Tiny
CARADIODOC
  • EXPERT
The clunk and vibration suggest a collapsed or broken engine mount. The vibration can be due to misaligned half shafts and binding inner cv joints, and it can be due to the two metal brackets of a mount rubbing against each other when the rubber isolater is deteriorated. That will transmit normal engine vibration into the body where you will feel it. Look for one end of the engine sitting too low. Next, watch how much and how roughly the engine rocks when a helper shifts between reverse and drive with the engine running.

The jerking could be a secondary symptom, or it could be due to stress on an electrical connector. Finding the cause of the clunking should come first.
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Friday, June 24th, 2016 AT 3:05 PM
Tiny
ALAN54
  • MEMBER
I checked the mounts using the method outlined in my Hanes manual and found no problems, When I had someone shift gears while I was watching the engine moved a1/2 to 1 inch, front to back when sifted from neutral to drive.
I have not had the front mount removed or loosened since I have had the car. I have disconnected the right mount a couple times to do repairs to the suspension, timing belt and steering unit. I didn't know that I was supposed to align the half shafts after removing them. I also replaced the front well bearings and didn't align the axels at that time either. Should I remove the front mount and check it, or is there something else that I should check first
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Sunday, June 26th, 2016 AT 12:23 PM
Tiny
CARADIODOC
  • EXPERT
Don't fret over the half shafts. That misalignment I was referring to is caused when one end of the drive train sits too low. All that's needed to fix that is to replace the collapsed mount. That will restore proper engine height and half shaft alignment.
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Monday, June 27th, 2016 AT 12:26 AM
Tiny
ALAN54
  • MEMBER
When I removed the front mount the rubber isolator fell out of its housing in pieces, and the mounting bracket was broke in three places. I replaced the bracket with one from salvage and installed a new mount. That took care of the clunk and at lest most of the vibration, Still have jerking back and forth when accelerating.
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Sunday, July 3rd, 2016 AT 12:42 PM
Tiny
CARADIODOC
  • EXPERT
Well, we're making progress.

Jerking can have a lot of causes with different subtle symptoms. A rocking engine can tug on a wiring harness that causes an intermittent connection in a connector terminal and an intermittent cutout of the ignition system or injector. A failing sensor, mostly the MAP sensor, can be supplying an incorrect signal voltage resulting in wrong fuel metering calculations. As long as the signal voltage is within acceptable limits, it won't set a diagnostic fault code, but it usually doesn't take very long for the failure to become bad enough that the Engine Computer does detect a problem and sets a code.

With no fault code, you have to view live data on a scanner to see if something doesn't look right or can provide a clue. Most scanners have a "record" feature that allows you to record a few seconds of sensor data when the problem occurs. Since the data passes through the scanner's memory, the recording actually starts a few seconds before the button was pressed. The recording can be reviewed slowly later to see what changed when the symptoms occurred.

Jerking can also be caused by worn steering and suspension parts. Clues are a sudden pull to one side, or a change in the centering of the steering wheel. The people at tire and alignment shops are experts at finding the causes of those things.
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Sunday, July 3rd, 2016 AT 8:59 PM
Tiny
ALAN54
  • MEMBER
Happy July 4th. I rebuilt the steering and suspension systems 2 years a go. The struts were replaced 4 years ago. I think that all of that is good, there is no pulling to either side and the steering wheel remains centered when driving straight. I replaced the rack and pinion both lower control arms and ball joints both tie rods and tie rod ends and the wheel bearing on both front wheels. Then had two new tires put on the front and an alignment done.
Will spent time today checking the vacuum system and the wiring connectors to try and find a problem I'll let you know what I find
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Monday, July 4th, 2016 AT 7:54 AM
Tiny
CARADIODOC
  • EXPERT
Dandy. I'll be out of town until Saturday night at the nation's second largest old car show swap meet in Iola, WI. They have wireless there but it was seriously overloaded last year. Don't panic if you don't hear from me until possibly Sunday night.
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Tuesday, July 5th, 2016 AT 11:34 PM
Tiny
ALAN54
  • MEMBER
I checked all the wiring connectors at the throttle body and around the engine compartment and found no loose connections or any broken wires. I did find 1 unhooked vacuum line. Running from the breather to the intake. I reconnected it with no noticeable improvement. I ran the codes using the key method. And got a code 15 speed sensor. I don't know if that will cause the problems that I am having. This weekend I will do a better check of the fuel system. And try to do a scan to see if there are any other codes that don't show up using the key method. Is there any other things that you think I should do at that time?
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Thursday, July 7th, 2016 AT 4:41 PM
Tiny
CARADIODOC
  • EXPERT
The only other thing I can think of for the vibration is a worn inner cv joint housing. That will cause a miserable steering wheel wobble at lower speeds under acceleration. It will be aggravated by turning at the same time, as in when exiting a parking lot. Also, replacing the side engine mount can make the problem worse or it can show up for the first time because those mounts set the sideways position of the engine, and moving the engine to one side as little as 1/8" from where it was will cause the cv joint's rollers to run back and forth in a different area. Extremely tiny amounts of wear will cause the rollers to bind, then the half shafts will tug on the spindle and therefore the steering linkage.

Try cleaning throttle plate on both sides and iac hole with choke cleaner then check fuel pressure with a gauge auto parts rent it.
https://http://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Sunday, July 10th, 2016 AT 11:16 PM

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