Transmission ?????

[oufan]

I have a 97 yukon 4x4 and it did something strange twice. When I was driving it started acting like the transmission was slipping. It would switch gears real hard into first and second. After I turned the ignition off it ran great for a few days then it did it again and I turned it off and it was fine that was 3 days ago. Help?

[2000CAYukon]

Is your Check Engine Light on? It would be a good idea to check for any stored codes. Code P1870 is pretty common on the 4L60E.

When the tranny shifts hard, it has detected a problem and raises the line pressure (this is sometimes called "limp" mode).

First thing is to check for codes.

//2000CAYukon

[Cropduster]

Had the exact thing happen on my "99" three weeks ago. I have a "16 bolt pan" on my transmission, some have a 17 bolt FYI. Took the car to the dealer and they quoted $1,000.00 to fix it with no warrenty, $2,700.00 with one. I replaced the 3 selonoid valves the one that controls the tork converter and (1) that control the 1st to second and (1) the 3rd to forth shift. Total cost $60.00 and 1 1/2 hrs time. There all under the pan and easy to do. Drove about 500mi since (200 towing). No problem.

Good Luck.

[oufan]

Thanks both of you for your suggestions they have helped alot. I had no idea what could have been the problem hope these work.