4L80E problems
4L80E problems So, I've put just under 2700 miles on my FLT Level 4-4L80E with billet input shaft. It's been running extremely well until the last 100-200 miles. I started noticing that it would carry first gear under part throttle. It'll carry it to 30ish mph, and then shift into second with a very firm shift. It does this in other gears as well. Also, when I put it in reverse, it takes a few seconds to engage. It does this even after being warmed up and driven for a bit. I thought maybe the friction components in the tranny had worn in, and whatever debris might have clogged the filter, creating a low line pressure issue. So, I drained the pan, replaced the filter with an OEM filter, and put new fluid in it.........still the same issue. Any help would be appreciated.
It was a little discolored and there was a little clutch material around the magnet, but no metal chunks or anything. What could cause the pcm to command a late shift?
The delayed reverse indicates low line pressure, likely a pump issue.
Putting a pressure gauge on it would be a good idea at this point.
Late shifting could be many things. The above mentioned low line pressure can cause slow movement of the shift valves and more time for the clutch to engage.
Late commanded shift could be caused by an engine code, trans code, VSS issue, etc.
Putting a pressure gauge on it would be a good idea at this point.
Late shifting could be many things. The above mentioned low line pressure can cause slow movement of the shift valves and more time for the clutch to engage.
Late commanded shift could be caused by an engine code, trans code, VSS issue, etc.
