4l80e Problems

Jjohns3825 · April 24, 2020

I have a 2005 Silverado 2500 HD with a 6.0L. It has 90,000 miles on it. I bought it with 86,000 miles on it a year and a half ago. When I took ownership it was leaking at rear of transmission. I took it to the shop and it was determined that the output shaft sleeve was worn, causing the rear seal to leak. It was then taken out and rebuilt. After that it would not stay in lockup. It would only lockup while going up a hill, like it was sensing a load on it and would kick out on level areas. It then started heating up and went into limp mode. I took it to a different trans shop and he determined that the pump was bad and filled the trans with metal, so he did another rebuild on it. Once put back in again, still wouldn't lockup as it should. So he tried this and that with it, even putting a completely different trans in it. Now it won't lockup at highway speed as all. It has 4.11 gears in it and runs around 3,000 rpm, but will come down to around 2,300 while in lockup at 70 MPH. The 2nd trans guy said the computer is saying it's going into lockup and staying, and all the pressures etc look as if it is in lockup but it isn't. Other than just throwing parts at it until something works, has anyone else been down this road? Thanks in advance

davester · April 24, 2020

Was the torque converter replaced? Are there any codes being generated by the TCM?

Jjohns3825 · April 24, 2020

When taken to the second transmission guy, he initially put in a new torque converter. Then when he went put in a different transmission it also had a new torque converter in it. He said he sent the first one back to the manufacturer, but with everything going on they will be a while getting back to him. There are no codes to be found anywhere. The last code was a random misfire that occurred last year. I put a new set of delco plugs and wires in at that time and it hasn't been back.