4L80E 3-4 Shift Problems
05-06-2011, 08:57 PM
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4L80E 3-4 Shift Problems This is a problem my buddy is having in his '99 Sierra...
Truck USED TO shift 3-4 at WOT without hesitation. He recently got it rebuilt, with new converter, all new everything. The build cost him around $4000 so everything was upgraded/replaced.
Now, his only problem with the trans is that at WOT it will not shift into 4th as hard as it shifts from 1-2, 2-3, and he's explained that it feels like it's slipping into 4th, as the RPMs rise, but he does not change gears immediately. It will go into 4th, but not as snappy as the other shifts.
Does anyone know what this problem could be?
I thought GM auto trans did not do 3-4 WOT shifts, but he swears it used to do it, and he is not the first owner of the truck, so the previous owner may have done something to the trans, that the trans builder un-did. Does that make sense?
Truck USED TO shift 3-4 at WOT without hesitation. He recently got it rebuilt, with new converter, all new everything. The build cost him around $4000 so everything was upgraded/replaced.
Now, his only problem with the trans is that at WOT it will not shift into 4th as hard as it shifts from 1-2, 2-3, and he's explained that it feels like it's slipping into 4th, as the RPMs rise, but he does not change gears immediately. It will go into 4th, but not as snappy as the other shifts.
Does anyone know what this problem could be?
I thought GM auto trans did not do 3-4 WOT shifts, but he swears it used to do it, and he is not the first owner of the truck, so the previous owner may have done something to the trans, that the trans builder un-did. Does that make sense?
