Hva slags Suburban har jeg kjøpt? (GMC Youkon XL 6.0)

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Se bort fra innlegget mitt ovenfor.    Har søkt litt om emnet og det ser ut til at problemet heller kan være det motsatte av det jeg tenkte, altså at lock-up slurer slik at girkassa øker linjetrykket når ECM detekterer sluringen. Da girer den hardt og problemet vil forsvinne når du slår av tenningen fordi ECM resettes.

Feilen kan komme av et defekt stempel i valve body som slipper oljetrykket forbi seg, slik at trykket til lock-up clutchen blir for lavt. 

Men i de fleste tilfeller blir problemet borte med en ny converter ser det ut til.

 

Dette var vel ikke til så mye hjelp da feilkildene fortsatt kan være så mye forskjellig.

 

Fant dette på fyllsizechevy:

 

 

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Update: I had my torque converter replaced and it fix the harsh shift. If you have access to a Tech II scanner or HP Tuners VCM Scanner, you can easily check it. The problem is obvious.


Select torque converter slip and watch the slip RPM. Go for a drive and get up to 65-70 MPH and wait for the TC to lock in 4th. Slowly add throttle and watch the slip. With a bad torque converter the TC slip RPM will rise above 100 or 200 or more. The slip will increase with throttle. Of course if you go high enough it will unlock and/or downshift to third.


A good TC will hold < 20 RPM before the PCM unlocks it. Mine would go into the 200+ slip range just adding throttle. I also noticed the tach would rise but not the speed as I added throttle. Clear indication the TC was slipping.


Some important notes (about the 2000 4L80E). May or may no apply to others years.


1. The 2000 4L80E had a problem with torque converters slipping. This is a known problem. I have read that 2000 was unique but I also have read the 99-02 were the same TC. I am not sure what is true on that.


2. The TC apply pressure is normally maxed out by design. This means the PCM doesn't have any extra to try and keep the TC locked. When there is slip, it doesn't know if it's TC slip or clutches so it raises the line pressure and voila, you have harsh shifts until you power cycle the key.


3. You may or many not have a P1870 TCC slip error. Mine generally didn't, but if I really worked at it (keeping the slip high for a couple of minutes climbing long hills), it would eventually set the code. Not having the code doesn't mean the TCC isn't slipping.


4. Mine cost $1100 out the door to replace including a new GM TC, fluids and misc stuff. The bill was $1300 but I had some other little stuff done.


5. Pressing the brake pedal does not unlock the TC. This is normal. The worse you do is set a brake pedal error code (no SES). 

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