Hi, I have a GMC Suburban 4X4 1500 with a 4L60E tranny. Last night it started hitting noticeably harder when it shifted into second and third gear. It was about a pint low. So I brought it up and it still hit hard. Went for a drive today and seemed ok. I am thinking since it has a 293,000 miles it's likely time. But why do you think the it hit hard and then smoothed out the next day. Computer maybe? Never saw a check engine light.

Eric

 

because the fluid was low...what did the fluid look like? Wouldn't be a bad idea to get a flush done or atleast replace the filter and make sure theses no metal in the filter/pan

 

Fluid was crystal clear. I think she is just getting old. I have a Goodwrench Tranny for it sitting in the factory shipping tub. I bought it along with the engine about three years ago. I have just been kinda busy and haven't got around to swapping it out.

Eric