I am dreading the day I kill my factory built 80E in the Tahoe or 85E in the Van. I hope it is a while off on both. This comment reminds me I am on borrowed time with 2 transmissions over 20 years old that have never been apart. My buddies cammed iron LS2 (LQ4 block, LS2 pistons, GenIV rods, 799 heads, TBSS intake) just did something to the 80E in his 2dr Yukon tonight. Tuning in Mexico, it went into limp after an epic tire smoking launch through 1st and into 2nd. Yukon has never broken them loose the way it did earlier. No codes, no weird noises, no slipping, just nothing but 2nd unless the negative cable is removed. Then it had 1st but as soon as it hits 2nd, it is in fail safe again, stuck in 2nd. It will only shift using HP Tuners to command it to shift. I can command 1st, 2nd, 3rd and Overdrive manually all day long with HP Tuners. Hopefully just an internal pressure switch problem that is sending the PCM a signal it cannot compute and thus forcing limp mode.