4T65E Transmission Issue. Help

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October 30th, 2011, 3:56 PM

tplp02

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4T65E Transmission Issue. Help

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oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

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ontFlipMirrorIndents/> <w:OverrideTableStyleHps/> </w:Compatibility> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]-->I would appreciate any ideas or help with this issue! Thank you in advance!

1999 Buick Lesabre Custom transmission "Jumping / Shuttering" when starting from stop with load on tranny (Usually starting on an upgrade) while in 1st gear. These symtoms were non existent until after I changed the transmission fluid / filter the first time. After fluid change, symptoms appeared immediately.

Transmission: 4T65E (GM Service Part Code MN3)

Symptoms:

1. Vehicle at operating temps.

2. When starting on a uphill grade with moderate throttle, transmission jumps/shutters the car while still in 1st. If you take your foot off throttle "jumping" will stop and a normal shift into 2nd will usually occur.

3. If you manually put shift lever into 1st gear, and accelerate, jumping will not occur, however if you manually put the tranny shift lever in OD, 2nd or 3rd jumping will return.

4. Jumping does not occur when vehicle is cold, only when warm.

5. Tranny seems to shift fine/smoothly into all other gears. This just happens from a stop when tranny is still in 1st. Shifts to 2nd fine.

Actions that I have taken: Checked...double and triple checked fluid levels!

1. Hooked up Snap-On Scanner and went into transmission settings and manually increased line pressure by going into PC Solenoid and increasing duty cycle (Pressure) to 10%. When I do this jumping / shutter goes away and shifting is fine. If I disconnect scanner or lower duty cycle back to 0% the symptoms return return. Repeated this step several times with same results.

2. Changed tranny filter / fluid. Fluid was pink, smelled good and the pan / magnet were normal with only slight / normal "Clutch mud" in the pan. Thermal element was fine. There was not other debris in the pan. Disassembled the filter and found no unusual debris.

3. All engine and tranny mounts were replaced (New)

4. Replace Throttle Position Sensor (New)

5. Replaced I.A.C.

6. All vacuum lines were checked with no leaks / issues.

7. Checked all History Codes with scanner. There were no codes set or in history on the engine or tranny side of system. Repeated this step several times...several times after duplicating symptoms...still no codes.

8. Cleared TAP Values and reset ECM / PCM by disconnecting battery overnight. Symptoms returned after a short time of driving.

9. Checked drive line / half shafts...no issues.

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October 30th, 2011, 4:26 PM

EinST

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If the condition of the fluid that came out originally were good (not burnt, not full of friction material or grits, etc.), some debris and sediments might have shifted inside the valve body. If you feel up to it, try disassembling and cleaning the valve body.

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October 30th, 2011, 4:34 PM

kevinkpk

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Why do you need to cross post?

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October 30th, 2011, 4:35 PM

tplp02

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I can manually adjust the line pressure and make the shutter go away, so this tells me it is most likely a pressure issue. I realize that debris may be in there..but I am thinking its a PC Solenoid or manifold press switch. Your thoughts?

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October 30th, 2011, 4:58 PM

EinST

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You stated that "symtoms were non existent until after I changed the transmission fluid / filter the first time." I don't see why the fresh fluid would affect electrical components and thus I'm rather ambivalent about replacing the PC solenoid. This "manifold press switch," are you referring to the MAP sensor? If so, my position on it is the same.

On a vehicle that old, usually the friction material suspended in the fluid makes up for the worn-out friction surfaces and thus it's better to leave it alone if the fluid sample looks like it's about had it. So, how was the condition of the fluid the first time?

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October 30th, 2011, 5:07 PM

tplp02

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Thank you for your suggestion. This is a very intelligent answer...which is what I am looking for! To answer your questions... These symptoms started as soon as I changed the fluid...and I mean immediately. This makes me think that perhaps I have sediment in the solenoids or Manifold Press. Switch. No the manifold Press switch is a component under the side cover which comes with the solenoid switch...you will see what I mean if you Google it. However, I did replace the MAP Sensor also in and unrelated issue..that was way before the tranny issue though. I also agree that friction material could be suspended in the fluid, however the fluid was almost immaculate. It did have a little mud in the pan and on the magnet, however I dont think that is was abnormal. Also the were NO symptoms before the fluid change. GM has a Service Bulletin with my exact symptoms listed and they cite the PC Solenoid. If I drop the tranny I am going to replace it all. The whole kit is 70.00...might as well. I just dont want to drop it for nothing which is why I am here...to learn. Thank you sir!

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October 30th, 2011, 5:13 PM

tplp02

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The Kit comes with a TCC Lock up Solenoid, two Shift Solenoids a PC Solenoid and a Manifold Pressure switch. I am also planning to replace the Speed sensor also.

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4T65E Transmission Issue. Help

4T65E Transmission Issue. Help

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