Major 4l60E Problem
Major 4l60E Problem I have rebuilt hundreds of 4L60E Transmissions but this one had me stumped. I rebuilt my own personal 1998 4l60E last year. After the full rebuild with everything I had great shift but no 4th gear. secound was awsome and the computer says that 4th was coming on but no 4th gear. I drove it like that for a few month just around town. Pulled it back apart after loosing 3rd. The 3-4 lugs blew out of the drum. I rebuilt with a new input drum and and checked everything over. Everything fires with an air check and 4th works great for the air check. Has Billet 4th servo. Take her back out on the road and great 1-2 and 3-4 still no 4th and TCC lock up is good. Downshift manual to D3 and the car seams to lockup or have way more overrunning then a normal LS1. Never did this before. Drove like this for a mile. Within that mile I lost 2nd. Now only 1st and 3rd. Removed trans and 2-4 band was dead and the overrun clutches were so bad that they had no friction meterial and were warped. Checked everything all over again. Used a different valve body and reinstalled. 1-2, 2-3 good stilll no 4th and when using overrun the same problem just killed band again and overrun clutches. I have no 4th ever and when going in D3 it kill overrun and 2-4 band. What could it be?
It does sound like you have a cross leak into the overun circuit, Could be a cracked forward clutch piston or seal. You probably are making the 3-4shift , But with the overun clutch on it would be trying to do what would be a weak transbrake affect since the input sprag must free wheel in fourth gear. The overun clutch and the band on in fourth would result in destroyed overun clutches and a burned band. Also you could have a bad or damaged pump stator groove worn on the inside.
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