1999 Denali Transmission Problem

When driving my 1999 Denali for an extended period of time, it begins shifting very hard, then eventually the SES light comes on.

When I shut the truck off, the SES light stays on, but it shifts fine until I make another extended trip, say 30 miles or longer. :disappoin

I've had the transmission rebuilt, what is the deal?

Anyone help?

When driving my 1999 Denali for an extended period of time, it begins shifting very hard, then eventually the SES light comes on.

When I shut the truck off, the SES light stays on, but it shifts fine until I make another extended trip, say 30 miles or longer. :disappoin

I've had the transmission rebuilt, what is the deal?

Anyone help?

I have the same problem with my 1996 Yukon and I used a OBDII code reader and gave me P1886 which is "Transaxle Shift, Timing Solenoid Performance". Now I think a Transmission shop would know how to fix it.
Usually transmission solenoids' are not expensive.
Good luck.

Hi,
I'll translate the codes, if you post them.
Is the shop willing to fix this under warrantee?

Take care, Eggert :bananasmi