Transmission slipping on LS?

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BennyCrac

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Location
Michigan
06 LS V8 94k miles
when cruising in 5th gear the transmission seems to slipping. only when holding my speed, just cruising at 50mph for example, never under actual acceleration. the way i describe how the car is acting is pretend you are just driving on dry roads and the traction control kicks in for no reason. that’s what this feels like. the rpms drop to idle for the split second that this happens and the car “jerks”. the rpms do not flare. i’ve read about the OD servo bore on this transmission going bad and this symptom happening. any suggestions on how to fix this problem? no check engine light or anything by the way.
 
That sounds a lot more like the classic marginal COP(s) problem to me. Transmission slipping would cause a jump in RPMs.
 
joegr said:
That sounds a lot more like the classic marginal COP(s) problem to me. Transmission slipping would cause a jump in RPMs.
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That’s exactly what i thought when i saw the rpm’s drop, the rpm’s should jump up if it was slipping. i did replace all 8 COPs about 3 years ago, spark plugs were replaced maybe 5 years ago. when the COPs were going bad before i replaced them i know what a misfire feels like. this is a much larger “jerk”. maybe a spark plug is completely fouled out. would that cause such a large “jerk”?
 
Well, I can't tell from here...
Sometimes the RFI from a bad COP can cause the PCM to reset. That would likely duplicate your symptoms. What brand COPs?
 
joegr said:
Well, I can't tell from here...
Sometimes the RFI from a bad COP can cause the PCM to reset. That would likely duplicate your symptoms. What brand COPs?
Click to expand...
Motorcraft COPs. actually just went for a drive to the gas station down the street. half mile away. snowing pretty bad so i accelerated pretty slowly, pretty much the same jerking feeling but this time the rpms rose.
 
BennyCrac said:
Motorcraft COPs. actually just went for a drive to the gas station down the street. half mile away. snowing pretty bad so i accelerated pretty slowly, pretty much the same jerking feeling but this time the rpms rose.
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very weird because until just now, the rpms always dropped down to idle for a split second when it happens. but i will say this, this past summer i changed the trans fluid + filter + valve body + shift solenoid pack. everything motorcraft besides the solenoid pack. solenoid pack was an ebay purchase.
 
BennyCrac said:
snowing pretty bad so i accelerated pretty slowly, pretty much the same jerking feeling but this time the rpms rose.
Click to expand...

Well your tires were most likely spinning... which kicked in the traction control. RPM's went up... and car applied the brakes automatically and cut power to the engine.
 
04_Sport_LS said:
Well your tires were most likely spinning... which kicked in the traction control. RPM's went up... and car applied the brakes automatically and cut power to the engine.
Click to expand...
it also happens when the roads are dry and just trying to hold my speed, so the tires aren’t always slipping when this happens, but what i did notice today is when my car jerks, the rpm’s go down to about 500 and the lights dim. let off the gas and the rpm’s and lights go back to normal. almost as if the car is about to stall. and this happens when not accelerating just when im holding my speed.
 
Sound like you may be having battery or alternator issues (most likely alternator).

Check the connections to the battery for corrosion. Especially the ground cable that is in the spare tire well.

Clean everything ... and spray with battery protector.

If that doesn't work... check your battery voltage. 12.6 is normal when not running. 14.2 is normal when engine is running.

If all that checks out... have your battery and alternator load tested.
 
04_Sport_LS said:
Sound like you may be having battery or alternator issues (most likely alternator).

Check the connections to the battery for corrosion. Especially the ground cable that is in the spare tire well.

Clean everything ... and spray with battery protector.

If that doesn't work... check your battery voltage. 12.6 is normal when not running. 14.2 is normal when engine is running.

If all that checks out... have your battery and alternator load tested.
Click to expand...
my electrical system is very beefy i built it for my sound system. 2 agm batteries, 300amp alternator and 0 gauge power and ground wires. (my problem does occur with the music low too btw) but i will check my voltage and connections, maybe something is loose
 
BennyCrac said:
my electrical system is very beefy i built it for my sound system. 2 agm batteries, 300amp alternator and 0 gauge power and ground wires. (my problem does occur with the music low too btw) but i will check my voltage and connections, maybe something is loose
Click to expand...
alternator is charging 14.5 volts, every connection is tight. i was doing a quick look at the engine bay and found that the hose clamp around the throttle body was super lose. that’s the only visual thing i can see right now.
 
BennyCrac said:
everything motorcraft besides the solenoid pack. solenoid pack was an ebay purchase.
Click to expand...

Just went back and re-read.

The Ebay solenoid packs can be questionable. Especially if you bought a "rebuilt" one. The Ebay people don't rebuild the solenoid pack. They just adjust the solenoids... and ship it as rebuilt. Been a few threads on this forum about that.
 
04_Sport_LS said:
Well your tires were most likely spinning... which kicked in the traction control. RPM's went up... and car applied the brakes automatically and cut power to the engine.
Click to expand...
This guy knows the LS better than most ...of course Joegr is a Google search for all of us but 04 Sport is correct
 
04_Sport_LS said:
Sound like you may be having battery or alternator issues (most likely alternator).

Check the connections to the battery for corrosion. Especially the ground cable that is in the spare tire well.

Clean everything ... and spray with battery protector.

If that doesn't work... check your battery voltage. 12.6 is normal when not running. 14.2 is normal when engine is running.

If all that checks out... have your battery and alternator load tested.
Click to expand...
I can't agree more with this statement...long story short ...a few weeks ago I noticed when I would roll my windows down in the morning on my way to work my headlights would dim ...my battery died completely at work on a -30 degree windchill winter day in Minnesota...nothing out of the ordinary in Minnesota winter ...but long story short I went to O Reillys and had them test the battery ...it was off way off and only a year old battery ....note: the Lincoln LS must have a proper vented MotorCraft battery from the stealership ... it's the best deal around and best battery around $130 walk out and even without the core the dealership only charged me $16 dollars ....point to story the O Riellys battery had a dead cell...since replacing with a 66 Motorcraft vented battery no issues what so ever car has more power and the aftermarket bluetooth radio works flawless ...it was cutting out with bad battery ...I'm not saying a battery is the cure all but start with a battery and go from there ...FWIW the Lincoln LS transmission is not the greatest transmissionever made ...but qith upgraded parts and a proper trans tech who knows his shit it can be a smooth and flawless tranny......get the correct battery in the car before anything
 
Last edited:
04_Sport_LS said:
Just went back and re-read.

The Ebay solenoid packs can be questionable. Especially if you bought a "rebuilt" one. The Ebay people don't rebuild the solenoid pack. They just adjust the solenoids... and ship it as rebuilt. Been a few threads on this forum about that.
Click to expand...
Again this is 100% correct ...you must buy a brand new Solenoid pack
 
BennyCrac said:
alternator is charging 14.5 volts, every connection is tight. i was doing a quick look at the engine bay and found that the hose clamp around the throttle body was super lose. that’s the only visual thing i can see right now.
Click to expand...

As Joe said... the PCM might be doing a reset. If there is RFI feedback from something (usually the ignition coils), then I could see having alternator problems since the PCM regulates alternator voltage.
 
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