6.5L 4L80E issues! doesnt want to go and no OD

YKdave

New member
Feb 18, 2010
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My co worker has an 93 3/4 ton 4x4 chev, 6.5L diesel, 4l80e trans.

He has nuked 3 trannies in this thing (i would say mostly due to improper installation at the dealer) and he is sick of dumping money into this thing as its just a beater truck. Trannies were rebuilds supplied by gm and installed by gm.

Now its parked again, with the 3rd trans acting up (less than 1000km on it)...

Now the symoptoms are:

When sitting at a stoplight, when trying to get rolling again it acts as though its in neutral. he says if you throw it in park while sitting and throw it into gear it helps, but still doesnt take off like it should.

Then once its rolling he says it shifts fine through to 3rd gear but will not go into 4th...

Fluid is full, no abnormal smells (or so he says...)
no idiot lights flashing


Any ideas?

He is on his last straw with this thing, he would like to ditch the 4l80e for a th400. No electronics, no bs. not worried about no overdrive or lockup as its just a bush beater. But if we could get this 4l80e figured out it would save the headache of a trans swap!
 
Last edited:

Mike L.

Got Sheep?
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Aug 12, 2006
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Fullerton CA
Put a scanner on it just in case there are hidden codes. If you go with the 4oo you will have to install a vacum regulator for the modulator to make it work.