Transmission must be overfilled to work

[trey3]

This has been bugging me for years. I have a 2000 Suburban with 290,000 miles. For the most part the original transmission works great. At about 75,000 miles I changed the transmission fluid (my first time, the truck's second) and filled it up to the appropriate mark on the dipstick, warm, level, in park. Went to drive it wouldn’t go into gear. I decided to add more fluid, turns out it needed A LOT more fluid. Ever since then it has to be packed, way up over the fill line. At first this made me nervous, but after over 200,000 miles and 7 or 8 changes, it obviously hasn’t hurt anything.

The best theory my buddies can come up with is it has the wrong dipstick. I find that hard to believe. Has anyone else ever heard of anything like this?

[DaveH71]

Should be around 6 - 7 qts if you are just dropping the pan, how many qts did you put in total?

[trey3]

Well that actually sounds about right. I usually put in what I take out. I'm going to change it next weekend and will be sure to measure.

[trey3]

It has the 16 bolt deep pan. Drained 5 quarts and added 5 quarts back. Still way up on the stick. While I was in there I decided to change the shift solenoids. On cool morning it was getting to the point I couldn't get up to 35mph without getting to 3500RPM. I was becoming a traffic problem. Now it will shift out of first before I get to the end of my street. Amazing difference. It also is about 500RPM less going 70 on the highway. I can also verify the design of the valve is different than the original. The hole is larger.